Engineers designing a new energy efficient product will make the first model called a
Answers
Engineers designing a new energy efficient product will make the first model called a prototype.
A prototype is the initial model that engineers create in order to test and evaluate the feasibility of their design. This model is usually made using cheaper and more readily available materials compared to the final product.
The purpose of the prototype is to identify any design flaws or areas for improvement, and make the necessary changes before moving forward with the production process. Engineers will often make multiple prototypes until they are satisfied with the design and performance of the product.
In the case of energy-efficient products, engineers will focus on developing a prototype that utilizes minimal energy consumption while still providing the desired level of functionality. This requires careful consideration of the materials and components used in the product, as well as the design of the product itself.
Once the prototype has been tested and refined, engineers can move on to creating the final product. By creating a prototype first, engineers can ensure that their design is both efficient and effective, ultimately resulting in a product that is better for both the environment and the consumer.
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Related Questions
which of the changes gas to solid gas to liquid, liquid to solid liquid to gas,solid to liquid solid to gas will involve an output and input of heat energy
Hurrryyyy
Answers
Answer:
Liquid to solid liquid to gas
Explanation:
Boiling a liquid result in a gas
PLEASE HELP ME WITH THIS QUESTION
Answers
If the volume is decreased to 2.6 L and pressure is decreased to 3.2 atm, then temperature become 156.98K.
This problem can be solved by using the concept of Ideal gas equation.
What ia ideal gas equation?The equation of ideal gas can be expressed as
PV = nRT
where,
P is the pressure of the gas
V is the volume taken
n is the number of moles of the gas
R is the gas constant = 6.314 J/ mol K
T is the temperature
Now from given data, we have the values of
V = 3.2 L
P = 5.5 atm
T = 53°C = 273 + 53 = 326 K
By substituting all the values, we get the value of n
3.2 × 5.5 = n × 6.314 × 326
17.6 = n × 2058.36
n = 17.6 / 2058.36
n = 0.0085 mol
Now, we have to find the temperature
n = 0.0085 mol
V = 2.6 L
P = 3.2 atm
By substituting all the values, we get
3.2 × 2.6 = 0.0085 × 6.314 × T
8.32 = 0.053 T
T = 8.32/ 0.053
T = 156.98 K
Thus, we concluded that if the volume is decreased to 2.6 L and pressure is decreased to 3.2 atm, then temperature become 156.98K.
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Cobalt-60, with a half-life of 5.0 days, is used in cancer radiation treatments. A hospital purchases a 30.0g supply of it and stores it on a shelf in a closet. The next time a hospital worker grabs the bottle, though, they find that it only contains 3.75 g remaining! Assuming the bottle had never been opened, how long was the bottle sitting on the shelf before the worked grabbed it?
Answers
Answer:
Bottle is sitting on the shelf for 15 days.
Explanation:
Given data:
Co-60 half life = 5 days
Total amount = 30.0 g
Amount left = 3.75 g
Time taken = ?
Solution:
AT time zero = 30 g
AT first half life= 30g /2 = 15 g
At 2nd half life = 15 g/ 2 = 7.5 g
At 3rd half life = 7.5 g/2 = 3.75 g
Now we will calculate the sitting time of bottle.
Half life = Time taken / number of half lives
3× 5 days = time taken
Time taken = 15 days
Bottle is sitting on the shelf for 15 days.
Given the equation representing a reaction: H + H --> H2, explain in terms of energy what is happening as the bond is being formed
Answers
Answer:
The formation of the bond releases energy. This is because the individual hydrogen atoms are more unstable than when they are joined together. Stability brings about the release of energy, and this would be an exothermic reaction.
Which of the following could be classified as producing a physical change?
A. Burning a candle
B. Leaving a bicycle outside to rust
C. Bending sheet metal
D. Toasting a slice of bread
Answers
Answer:
C. Bending sheet metal.
Explanation:
The metal is still intact. No change in chemical bonds have occurred.
Burning a candle is converting wax into heat, CO2 and carbon soot.
A rusting bicycle is converting goof iron, Fe, into iron oxide (rust, Fe2O3)
Toasting bread is more difficult to define. If the bread is just warmed, then it is physical. If it is toasted (browned/burned), then a few surface molecules have been converted into tasty carcinogens, my favorite poison.
What makes a metal and a non metal most
reactive? Where in the PT will you find the most
reactive metal and the most reactive non metal.?
Answers
Answer:
Explanation:
The reactivity of elements in the periodic table is based on the number of electrons in there outermost shell. Elements (metals) that have few electrons in there outermost shell are highly reactive because it is easier to lose fewer number of electrons (in the outermost shell during a reaction) than to lose more electrons in the outermost shell - thus metals that have one electron in there outermost shell are most reactive and are more reactive than those that have two electrons in there outermost shell. Hence, metals in group 1 are the most reactive metals because they all have one electron in there outermost shell.
Non-metals that have fewer electrons to complete there octet configuration are highly reactive because it is easier to gain fewer number of electrons (in the outermost shell during a reaction) than to gain more number of electrons - thus nonmetals that have seven electrons in there outermost shell are more reactive than nonmetals that have six electrons in there outermost shell. Hence, nonmetals in group 17 are the most reactive nonmetals because they contain seven electrons and have just one electron left to complete there octet configuration.
Determina la masa atómica promedio del cobre teniendo en cuenta que este elemento se encuentra en la naturaleza en forma de dos isótopos: el 65Cu con una abundancia del 69,09% y una masa de 62,9298 u.M.A.; y el 63Cu con una abundancia del 30,91% y una masa de 64,9278 u.M.A.
Answers
Answer:
63.5474U.M.A. es la masa atómica promedio del cobre
Explanation:
La masa atómica promedio de un átomo es definida como la suma de las masas de los isótopos multiplicada por su abundancia. Para el caso del cobre que tiene dos isótopos:
Cu = Masa 65Cu*Abundancia + Masa 63Cu*Abundancia
Reemplazando con los valores dados en el problema:
Cu = 62.9298U.M.A.*0.6909 + 64.9278U.M.A.*0.3091
Cu = 63.5474U.M.A. es la masa atómica promedio del cobre
The conjugate base of CH3NH3+ is A) CH3NH2+ B) CH3NH2-C) CH3NH+ D) CH3NH2
Answers
This base is weak; it is methylamine. Methylamine, CH3NH2, and ammonia, NH3, are chemically quite similar.
What is CH3NH2 conjugate acid?Because it may give up an electron pair, CH3NH2 C H 3 N H 2 is a base. It transforms into its conjugate acid when it gives up an electron and accepts a proton. The conjugate acid of CH3NH2 C H 3 N H 2 is CH3NH+3 C H 3 N H 3 + because it contains an additional hydrogen atom and an additional positive charge compared to its base. This makes CH3NH3+ a weak acid.
Because of CH3NH3+, a Bronsted acid, the salt is hence acidic. Moreover, the CH3NH3+ ion's name must be methyl ammonium ion. It belongs to the family of methylamines and is a primary aliphatic amine with one carbon. It is a base of methylammonium conjugated. The aqueous solution of methylamine appears as a colorless to yellow gas.
Therefore the correct answer is option D ) CH3NH2
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Why shouldn't you flake off adsorbent?
Answers
Adsorbent materials, such as activated carbon or silica gel, are designed to attract and hold onto specific molecules or particles from a fluid or gas. If you flake off the adsorbent, you risk releasing those molecules or particles back into the surrounding environment, potentially causing contamination or harm.
Flaking off the adsorbent can disrupt its ability to effectively remove unwanted substances, reducing its overall efficiency and effectiveness. Therefore, it is important to handle adsorbent materials carefully and avoid flaking them off whenever possible.
1. Safety: Adsorbents are often used to remove contaminants, toxins, or other harmful substances from materials or environments. Flaking off adsorbent could release these contaminants, posing a risk to your health and the environment.
2. Effectiveness: Adsorbents work by providing a large surface area for the adsorption of targeted substances. Flaking off adsorbent may reduce its surface area, decreasing its overall effectiveness in capturing and holding contaminants.
3. Waste: Flaking off adsorbent may lead to unnecessary waste, as the adsorbent material will no longer be used to its full capacity. This could result in increased costs for additional adsorbent materials or disposal of partially used adsorbents.
In summary, you shouldn't flake off adsorbent to ensure safety, maintain its effectiveness, and minimize waste.
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You should not flake off adsorbent because doing so can negatively impact its efficiency and compromise the purpose it serves.
Adsorbents are materials designed to adhere or hold molecules of a substance on their surface, typically used in purification and separation processes. They have a high surface area and porous structure, which enables them to effectively adsorb and retain impurities. Flaking off adsorbent may result in the loss of these crucial properties. The process can cause damage to the porous structure, reducing the overall surface area available for adsorption. This, in turn, reduces the adsorbent's capacity to capture and retain impurities, ultimately affecting the purity of the end product.
Furthermore, flaking off adsorbent can lead to the generation of fine particles or dust, these particles may cause contamination in the process or system where the adsorbent is employed, impacting product quality and posing potential safety hazards. Lastly, the act of flaking off adsorbent may also increase the likelihood of human exposure to harmful substances that are adsorbed onto the material, this exposure can lead to health risks, especially when dealing with toxic or hazardous compounds. You should not flake off adsorbent because doing so can negatively impact its efficiency and compromise the purpose it serves.
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If 3. 5 kJ ofenerg are added to a 28. 2 g sample of iron at 20c what is the final tempature of the iron in kelvins refer to table 1 for specific heat of iron
Answers
The final temperature of the iron in Kelvin is 320.75 K.
To find the final temperature, we need to use the formula for heat transfer:
q = mcΔT,
where q is the heat added, m is the mass of the iron, c is the specific heat capacity of iron, and ΔT is the change in temperature.
It is given that:
q = 3.5 kJ = 3500 J (converted to joules)
m = 28.2 g
Initial temperature, Ti = 20°C
Specific heat capacity of iron, c = 0.449 J/g·°C
Now, we need to find the change in temperature (ΔT) using the formula:
3500 J = 28.2 g × 0.449 J/g·°C × ΔT
ΔT = 3500 J / (28.2 g × 0.449 J/g·°C) ≈ 27.6°C
Then, we find the final temperature in Celsius:
T = Ti + ΔT = 20°C + 27.6°C ≈ 47.6°C
Finally, we convert the final temperature to Kelvin:
T(K) = T(°C) + 273.15 = 47.6°C + 273.15 ≈ 320.75 K
So, the final temperature is approximately 320.75 K.
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Which of these are PHYSICAL changes?
А.
cutting, tearing, freezing, thawing, folding.
mixing without chemical changes
B.
burning, rusting, forming a new substance from
two different substances, exploding, cooking
Answers
Answer:
the answer to this problem is a
Lab: Acids and Bases Assignment: Lab Report
What is the purpose of the lab, the importance of the topic, and the question you are trying to answer?
What is your hypothesis (or hypotheses) for this experiment?
What methods are you using to test this (or each) hypothesis?
Section II: Data and Observations
Locate the data and observations collected in your lab guide. What are the key results? How would you best summarize the data to relate your findings?
Do you have quantitative data (numerical results or calculations)? Do you have qualitative data (written observations and descriptions)? How can you organize this date for your report?
Section III: Analysis and Discussion
What do the key results indicate?
If you constructed graphs, what trends do they indicate in your data?
Were there any problems with the experiment or the methods? Did you have any surprising results?
Section IV: Conclusions
What do the results tell you about your hypothesis(es)?
How do the data support your claim above?
If you could repeat the experiment and make it better, what would you do differently and why?
Answers
Answer:
Lab: Acids and Bases Assignment: Lab Report
The main point is to help the scientific method and to also see how it works.Sometimes people refer to the tentative answer as "an educated guess." Keep in mind, though, that the hypothesis also has to be testable since the next step is to do an experiment to determine whether or not the hypothesis is right! A hypothesis leads to one or more predictions that can be tested by experimenting.>State the hypotheses. Every hypothesis test requires the analyst to state a null hypothesis and an alternative hypothesis. The hypotheses are stated in such a way that they are mutually exclusive. That is, if one is true, the other must be false; and vice versa.>Formulate an analysis plan. The analysis plan describes how to use sample data to accept or reject the null hypothesis. It should specify the following elements.>Analyze sample data.Using sample data, perform computations called for in the analysis plan.>Interpret the results. If the sample findings are unlikely, given the null hypothesis, the researcher rejects the null hypothesis. Typically, this involves comparing the P-value to the significance level, and rejecting the null hypothesis when the P-value is less than the significance level and etc.Section II: Data and Observations
In a lab guide, the key results are those that support my working hypotheses or serve to reject these assumptions. Moreover, the key results may also be other discoveries that are important to understand the processes and/or mechanisms investigated in the experiment.•?
Section III: Analysis and Discussion
Key Results are the measures and milestones that indicate how you know you will accomplish our Objective.A linear pattern is a continuous decrease or increase in numbers over time. On a graph, this data appears as a straight line angled diagonally up or down (the angle may be steep or shallow). So the trend either can be upward or downward.Yes, i was surprised and learn so much and it was no problem.Section IV: Conclusions
Results will tell you which hypothesis is true.describe specific part of the procedure.If I were able to repeat the lab and do it differently I would try to do two different things to improve it. I would try to create the model in a simpler manner that allowed me to better see how the erosion factored in. I would also try to take more detailed notes on it if I were to repeat it.i hope it's helpAnswer:
anyone know the section II answers for a lab like this but its the thermal energy transfer lab
Explanation:
^^
help me asap!!!
Considering the temperature vs. time graph below, how does the temperature at the beginning of a change of state compare with the temperature at the end of the change?
The temperature is always lower.
The temperature is always the same.
The temperature is usually lower.
The temperature is usually higher.
Answers
The temperature is always the same.
Explanation:Temperature vs. time graphs help show how phase changes occur over time.
Temperature During Changes of State
To understand how temperature changes during phase changes, we need to understand what a phase change is. A phase change occurs when the state of matter changes. For example, changing from a solid to a liquid. When a phase change occurs, the intermolecular forces that hold the molecules together are broken. This takes energy. So, if the state of matter is being changed, all of the new energy goes to breaking the forces, not increasing temperature. Thus, the temperature never changes during a phase change.
Reading the Graph
We don't need to know the information above in order to answer this question. Instead, we can simply read the graph. The points 2 and 4 represent the changes in state of matter. We know that there are 3 states of matter that occur in the same order. Solids are the coldest, then liquids, then gases are the hottest. So, 1, 3, and 5 are those states of matter respectively. Thus, the regions 2 and 4 in between these states of matter must be the phase changes.
Both 2 and 4 are horizontal lines. This means that the temperature is not changing at these points. So, we know that temperature does not change during a phase change.
The way the temperature changes at the end is always higher than how it changes at the beginning. Option D
What is change of state?A change of state refers to the transformation or conversion of matter from one physical state to another. Matter can exist in three primary states: solid, liquid, and gas. The change of state occurs when there is a transition between these states, typically as a result of altering temperature or pressure.
Since the molecules acquire energy in the process and they move faster, the way the temperature changes at the end is always higher than how it changes at the beginning.
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What is the name of the molecule below?
O A. 1-ethyne
B. 1-butyne
C. 2-butyne
D. 2-ethyne
Answers
Answer:
C.) 2-butyne
Explanation:
Since the molecule has 4 central carbons, it has the prefix but-.
Since the molecule has a triple bond between central carbons, it has an ending of -yne.
Since the triple bond starts on the second carbon, it has a 2 - prefix.
How many atoms of N are in 0.755 mol of N2? ( mole conversion)
Answers
The number of atoms N in 0.755 mol of N₂ : 9.09 x 10²³
Further explanationThe mole is the number of particles(molecules, atoms, ions) contained in a substance
1 mol = 6.02.10²³ particles
Can be formulated
N=n x No
N = number of particles
n = mol
No = Avogadro's = 6.02.10²³
moles of N in 0.755 mol N₂ :
\(\tt 2\times 0.755=1.51~moles\)
The number of atoms N :
\(\tt 1.51\times 6.02\times 10^{23}=9.09\times 10^{23}~atoms\)
Which of the following is an energy conservation practice?
Raise the temperature on a water heater.
Wash clothes in cold water instead of warm.
Run the washing machine with smaller loads.
Lower the thermostat's temperature in the summer.
Answers
Out of the options listed, washing clothes in cold water instead of warm is an energy conservation practice. Option C is correct.
Energy conservation refers to the practice of reducing the amount of energy used in daily activities while still achieving the desired results. This practice is essential in reducing greenhouse gas emissions, combating climate change, and reducing reliance on non-renewable energy sources.
This practice reduces the amount of energy required to heat water, which saves both energy and money. Heating water accounts for a significant amount of energy use in households, and by reducing the temperature, a significant amount of energy can be saved.
Raising the temperature on a water heater, on the other hand, is not an energy conservation practice. This action leads to increased energy consumption, as the water heater needs to work harder to maintain the desired temperature. It is recommended to keep the temperature of the water heater at 120°F to reduce energy consumption.
Running the washing machine with smaller loads can reduce water usage, but it may not necessarily reduce energy usage. Energy consumption is directly related to the amount of water used, the temperature of the water, and the duration of the washing cycle.
Lowering the thermostat's temperature in the summer can save energy if it leads to a reduction in air conditioning usage. However, if it leads to increased use of fans or other cooling equipment, it may not result in energy conservation.
In conclusion, washing clothes in cold water instead of warm is an energy conservation practice that households can adopt to reduce energy usage, save money, and contribute to environmental sustainability. Option C.
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i need this asap will give brainliest
Answers
Answer:
Explanation:
42.32
Hope this helps sorry if wrong
A 2.5 molar solution contains 0.97 g of NaOH. What would be the volume of this
solution in mL?
Answers
Answer:
9.7 ml
Explanation:
Molarity = 2.5 M
Mass = 0.97g
Volume = ?
The relationship between these quantities is;
Molarity = Number of moles / Volume
Number of moles = Mass / Molar mass
Molar mass of NaOH = 40g/mol
Number of moles = 0.97 / 40 = 0.02425 mol
Volume = Number of moles / Molarity = 0.02425 / 2.5 = 0.0097 L
1000 ml = 1L
x = 0.0097 L
x = 0.0097 * 1000 = 9.7 ml
Order the following atoms from smallest to largest atomic radius: C, N, P
Answers
Answer:
N ∠ C ∠ P
Explanation:
Atomic radius:
It is define as the distance from nucleus of an atom the outer most electronic shell.
As we move down the group atomic radii increased because of increase of atomic number. Electrons are added in next level cause the atomic radii to increased. The hold of nucleus on valance shell become weaker because of shielding of electrons thus size of atom increased.
When we move from left to right across the periodic table electron are added in the same shell at the same time protons are also added in the nucleus hence positive charge is going to increase and this effect lead to the greater nuclear attraction. The electrons are pull towards the nucleus and valance shell get closer to the nucleus and atomic radii decreases.
Carbon and nitrogen are present in period 2 while phosphorus is present in period 3 thus phosphorus has largest atomic radii. Carbon and nitrogen are present in same period but nitrogen is more right as compared to the carbon which means nitrogen has one more valence electron thus its size is smaller than carbon.
Values of atomic radii.
P = 98pm
C = 67pm
N = 65 pm
N ∠ C ∠ P
Please help!
Which of these statements is true about a specialized cell?
The cell has only the genes it needs for its function
The cell has a complete set of genes and all of these genes are expressed
The cell has a complete set of genes but only a fraction of these genes are expressed
Answers
Statements C. The cell has a complete set of genes but only a fraction of these genes are expressed is true about a specialized cell.
What is the process of cell specialization?The process of cell specialization makes reference to the expression of a given group of genes in a cell so the cell generates specific proteins that are required to play certain functions.
Therefore, with this data, we can see that the process of cell specialization is based on the expression of a specific group of genes and it leads to specific structural or enzymatic proteins.
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In rutherford's famous experiment, he shot heavy, fast moving, positive alpha particles at a thin gold foil. based on thomson's plum pudding model of the atom, what did rutherford expect to happen, and why? all the alpha particles would be deflected by the foil because of the even distribution of mass and charge throughout the atom. all the alpha particles would pass straight through the foil because of the even distribution of mass and charge throughout the atom. most of the alpha particles would become embedded in the foil because they are attracted to the negative electrons in the atom. some of the alpha particles would be deflected and some would pass through, because of the negative charge of the electron cloud.
Answers
Based on Thomson's plum pudding model of the atom, what did Rutherford expect All the alpha particles would pass straight through the foil because of the even distribution of mass and charge throughout the atom.
What happened when Rutherford fired alpha particles at gold foil?Alpha particles, which have a positive charge, were fired at a piece of gold foil. The vast majority of alpha particles passed right through. This demonstrated that the gold atoms were primarily empty space.The gold foil experiment by Rutherford demonstrated that the atom is mostly empty space with a tiny, dense, positively charged nucleus. Rutherford proposed the nuclear model of the atom based on these findings.With his gold-foil experiment, physicist Ernest Rutherford established the nuclear theory of the atom. When he fired an alpha particle beam at a sheet of gold foil, some of the particles were deflected. He concluded that the deflections were caused by a tiny, dense nucleus.The nucleus of an atom is very small. There is a lot of empty space surrounding the nucleus. The nucleus is a very small positively charged region that contains the entire mass of an atom. Electrons are dispersed in the empty space surrounding the nucleus.
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Blue bowling ball rolled with a force of 15 N accelerates at a rate of 3 m/sec2 a second red ball rolled with the same force accelerates at 4 m/sec2. What are the masses of the two balls?
Answers
Answer:
1. Mass of the blue ball is 5 kg.
2. Mass of the red ball is 3.75 kg.
Explanation:
The following data were obtained from the question:
For the blue ball:
Force (F) = 15 N
Acceleration (a) = 3 m/s²
Mass (m) =.?
Force the red ball:
Force (F) = the same with that of the blue ball = 15 N
Acceleration (a) = 4 m/s²
Mass (m) =.?
1. Determination of the mass of the blue ball.
Force (F) = 15 N
Acceleration (a) = 3 m/s²
Mass (m) =.?
Force (F) = mass (m) × acceleration (a)
F = ma
15 = m × 3
Divide both side by 3
m = 15/3
m = 5 kg
Therefore, the mass of the blue ball is 5 kg
2. Determination of the mass of the red ball.
Force (F) = 15 N
Acceleration (a) = 4 m/s²
Mass (m) =.?
Force (F) = mass (m) × acceleration (a)
F = ma
15 = m × 4
Divide both side by 4
m = 15/4
m = 3.75 kg
Therefore, the mass of the blue ball is 3.75 kg
The end point for a titration can be determined graphically. The end point volume for a second derivative plot corresponds to: . A) the volume titrant added where the second derivative curve crosses the x-axis. B) the volume titrant added where the second derivative curve has maximum slope. C) the volume titrant added where the second derivative curve crosses the y-axis. D) the volume titrant added where the second derivative curve has minimum slope. E) the volume titrant added where the second derivative curve has a maximum negative slope.
Answers
The volume titrant added where the second derivative curve has the greatest slope is the endpoint volume for a second derivative plot. The volume titrant added where the second derivative curve has the greatest slope, Option B, is the correct answer.
What is the Titration curve?The titration curve is a graphical representation of a chemical reaction where the stoichiometric quantity of one reactant is gradually added to another until the reaction reaches its endpoint.
The second derivative plot can be used to determine the endpoint of a titration. The second derivative is the rate of change of the slope of the titration curve. In the second derivative curve, the endpoint is recognized as the point with the maximum slope.
As a result, the end volume in a titration corresponds to the volume of titrant added where the second derivative curve has a maximum slope.
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A substance has a specific heat of 0.870 j/g°c. it requires 2,000.0 joules to increase the temperature of 10.0 grams of the substance from its original temperature to its final temperature. by how many degrees did the substance increase? a. 87.0°c b. 174°c c. 230°c d. 1,740°c
Answers
Explanation:
2000 J = .870 J/(g C) * 10 g * d where d is the degree change
2000/ (.870 *10) = d = ~230 C
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1
a
C
Copper(II) nitrate decomposes on heating. The reaction is endothermic.
2Cu(NO),(s) → 2CuO(s) + 4NO2(g) + 0,(9)
Sketch a reaction pathway diagram for this reaction to include the
activation energy
[3]
b Draw an energy cycle to calculate the standard enthalpy change for
this reaction, using enthalpy changes of formation.
[3]
Calculate the enthalpy change for this reaction using the following
enthalpy changes of formation.
AH, [Cu(NO, ),(s)] = -302.9 kJ mol-'
AH, [CuO(s)] =-157.3 kJ mol-!
AH [NO,(g)] = +33.2 kJ mol-!
[3]
d Copper(II) sulfate is soluble in water. A student dissolved 25.0 g of
copper(II) sulfate in 100 cm of water in a polystyrene beaker stirring
all the time. The temperature of the water fell by 2.9 °C.
i Calculate the enthalpy change of solution of copper(II) sulfate.
(specific heat capacity of water = 4.18 Jg1 °C ; relative
molecular mass of copper(II) sulfate = 249.7 g mol-')
[3]
ii Suggest one source of error in this experiment and explain how
the error affects the results.
[2]
[Total: 14]
Answers
This problem provides information about the decomposition of copper(II) nitrate to copper(II) oxide and dinitrogen monoxide; for example, it is endothermic, the enthalpies of formation and the chemical reaction, as well as copper (II) sulfate which when dissolved in water, exhibits a temperature decrease:
\(2Cu(NO_3)_2(s) \rightarrow 2CuO(s) + 4NO_2(g) + O_2(g)\)
First of all, we can draw the reaction pathway as shown on the attached figure, by taking into account the positive enthalpy change as it is endothermic, so that the products turn out with higher energy than the reactants, for it to be positive. In addition, keep in mind that top point is the activation energy the reaction needs to take place.
Next, we calculate the enthalpy change for this reaction by using the general formula which subtracts the enthalpy of formation of products and reactants with each species' correct stoichiometric coefficient:
\(\Delta H=2\Delta _fH_{CuO}+4\Delta _fH_{NO_2}+\Delta _fH_{O_2}-2\Delta _fH_{Cu(NO_3)_2}\)
So we plug in the given enthalpies of formation:
\(\Delta H=2(-157.3)+4(33.2)+(0)-2(-302.9)=424.0 kJ/mol\)
Finally, we go over the calorimetry experiment, whereby the total heat absorbed by the copper(II) sulfate is calculated via the general heat equation, which includes the heat loss from the solution of water and the salt:
\(Q_{rxn}=-mC_w\Delta T\\\\Q_{rxn}=-(100+25)g*4.18\frac{J}{g\°C}*-2.9\°C=1515.25J\)
By dividing the previous answer by the moles of salt:
\(n=25.0g*\frac{1mol}{249.7g}=0.100mol\)
We can obtain the enthalpy change of solution of the copper salt:
\(\Delta _{dissolution}H=\frac{1,515.25J}{0.100mol} \\\\\Delta _{dissolution}H=15,134J/mol=15.1kJ/mol\)
To conclude, it is important to note that one possible source of error is we are assuming the solution has the same specific heat to that of water and that is not necessarily true. Also, we are neglecting any heat transfer to and from the surroundings despite the polystyrene beaker is considered a heat isolator, which means the results cannot necesarilly be accurate and the enthalpy change could have turned out higher or lower in a rigoruous experiment.
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What is the percent yield when a reaction vessel that initially contains 68.0 kg CH4 and excess steam yields 16.9 kg H2
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When a reaction vessel initially containing 68.0 kg \(CH_4\) and excess steam yields 16.9 kg \(H_2\), the percent yield would be 49.8%
Percent yieldRecall that: percent yield = yield/theoretical yield x 100%
From the equation of the reaction:
\(CH_4 + 2H_2O --- > CO_2 + 4H_2\)
The mole ratio of methane to steam is 1:4.
Mole of 68.0 kg methane = 68000/16.0 = 44239.4 moles
Equivalent mole of \(H_2\)= 16,957.6 moles
Mass of 16,957.6 moles \(H_2\) = 16,957.6 x 2 = 33,915.2 grams or 33.92 kg
Percent yield = 16.9/33.92 x 100% = 49.8%
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The percentage yield of the reaction that yields 16.9 kilograms of Hydrogen gas, H₂ is 66.3%
Balanced equationCH₄ + H₂O —> CO + 3H₂
Molar mass of CH₄ = 16 g/mol
Mass of CH₄ from the balanced equation = 1 × 16 = 16 g = 0.016 Kg
Molar mass of H₂ = 2 g/mol
Mass of H₂ from the balanced equation = 3 × 2 = 6 g = 0.006 Kg
SUMMARY
From the balanced equation above,
0.016 Kg of CH₄ reacted to produce 0.006 Kg of H₂
How to determine the theoretical yield of H₂From the balanced equation above,
0.016 Kg of CH₄ reacted to produce 0.006 Kg of H₂
Therefore,
68 Kg of CH₄ will react to produce = (68 × 0.006) / 0.016 = 25.5 Kg of H₂
How to determine the percentage yield Actual yield of H₂ = 16.9 KgTheoretical yield of H₂ = 25.5 KgPercentage yield =?Percentage yield = (Actual / Theoretical) × 100
Percentage yield = (16.9 / 25.5) ×100
Percentage yield = 66.3%
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what occurs when the vapor pressure of a lquid is equal to the external atmospheric pressure
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Answer:
The change from a liquid phase to a gaseous phase occurs when the vapor pressure of the liquid is equal to the atmospheric pressure exerted on the liquid.
Explanation:
Boiling is a physical change and molecules are not chemically altered during the process.
describe un modelo matemático para representar lo que sucede en cada una de las reacciones químicas (incluye toda la simbología que puedas) y clasifícalas según consideres de acuerdo con lo abordado en el tema.
1. El hidrógeno molecular reacciona con el oxígeno molecular y produce agua
2. El Óxido de calcio reacciona con el agua y produce hidróxido de calcio
3. El sulfuro de hierro (II) se produce cuando reacciona el azufre y el hierro en su forma atómica
4. El ácido sulfuroso se descompone por la acción de calor en dióxido de azufre gaseoso y agua
5. El carbonato de calcio se descompone por la acción de calor en oxido de calcio y dióxido de carbono gaseoso.
6. El magnesio reacciona con el ácido clorhídrico y produce dióxido de magnesio e hidrógeno gaseoso.
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Answers
Responder:
2H2 + O2 → 2H2O
CaO + H2O → Ca (OH) 2
Fe + S → FeS
H2SO3 → SO2 + H2O
CaCO3 → CaO + CO2
Explicación:
2H2 + O2 → 2H2O
2 moléculas de hidrógeno gaseoso reaccionan con oxigente para producir 2 moléculas de agua
CaO + H2O → Ca (OH) 2
El óxido de calcio reacciona con el agua para producir hidróxido de calcio.
Fe + S → FeS
El hierro reacciona con el azufre para producir sulfuro de hierro.
H2SO3 → SO2 + H2O
Por descomposición, el ácido sulfuroso se descompone para producir dióxido de azufre y agua.
CaCO3 → CaO + CO2
El carbonato de calcio se descompone para producir óxido de calcio y dióxido de carbono.
Which feature is shared by all three-carbon monosaccharides?
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The features are shared by all three-carbon monosaccharides, They are all pentoses. In their linear forms, they all contain carbon carboxyl and several hydroxyl functional groups. In their linear forms, they all contain a carbonyl and several hydroxyl functional groups.
Carbon is used in some form in almost every industry in the world. It is used as fuel in the form of coal, methane gas, and crude oil (used to make gasoline). It is used to make all sorts of materials, including plastics and alloys such as steel (a combination of carbon and iron).
Life on Earth cannot exist without carbon. This allows carbon to readily form bonds with other atoms, giving it flexibility in the forms and functions that biomolecules such as DNA and RNA can adopt, and is essential for growth and replication, the defining properties of life. This is partly due to
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The direct vaporization of a solid without passing through its liquid state is called
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The direct vaporization of a solid without passing through its liquid state is called Sublimation.
In the physics aspect, sublimation is the conversion of a substance from the state of solid to the gaseous state without its becoming transiting to a liquid state. The best example of sublimation is the vaporization of carbon dioxide in a frozen state or called dry ice produced at ordinary atmospheric pressure as well as temperature.
The term sublimation refers to a kind of physical change of state and it is generally not used to describe any kind of transformation from a solid state to a gas state in a particular chemical reaction. Sublimation is also used as a generic term usually for describing a solid-to-gas transition which is followed by a gas-to-solid type transition.
Sublimation is a type of endothermic process that occurs at specific temperatures and pressures below a triple point of a substance in its phase diagram that corresponds to the lowest pressure at which the substance involved tends to exist as a liquid.
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