(01. 05 MC)





During an experiment a thermometer was placed in a beaker containing hydrogen peroxide. The following observations were recorded when yeast granules were added to hydrogen peroxide.





Observation 1: Fizzing and bubbling took place.




Observation 2: The temperature began to rise.





Based on the observation, justify the type of change (physical or chemical) that took place

The wall of copper (thermal conductivity = 400 W/m*K) that needs to provide the same insulation as a 4-cm polystyrene board (thermal conductivity = 0.04 W/m*K) must have a thickness of 400 meters.

The insulation of a material is directly proportional to the R factor. The higher the R the higher is the insulation of the material.

The R factor is given by:  

\( R = \frac{L}{k} \)   (1)

Where:

L: is the thickness

k: is the thermal conductivity

The thickness of the copper wall can be calculated with equation (1):

\( L_{copper} = R*k_{copper} \)

Where:

\( k_{copper} \): is the thermal conductivity of copper = 400 W/(m*K)  

Since the copper wall must provide the same insulation as a polystyrene board, we have:

\( L_{copper} = R*k_{copper} = \frac{L_{polystyrene}}{k_{polystyrene}}*k_{copper} = \frac{0.04 m}{0.04 W/(m*K)}*400 W/(m*K) = 400 m \)

Therefore, the copper wall must have a thickness of 400 meters.

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Electrical energy is the energy stored in an electric field, and it is related to the voltage across a capacitor and the charge stored on its plates. When a capacitor is charged, energy is stored in the electric field between the plates, and this energy can be released when the capacitor is discharged.

The electrical energy stored in a capacitor is given by :-E = (1/2) * C * V²

where E is the electrical energy stored, C is the capacitance of the capacitor, and V is the voltage across the capacitor.

Magnetic energy is the energy stored in a magnetic field, and it is related to the current flowing through an inductor and the magnetic flux through its coils.

When an inductor is energized, energy is stored in the magnetic field around the coils, and this energy can be released when the inductor is de-energized. The magnetic energy stored in an inductor is given by:

E = (1/2) * L * I^2

where E is the magnetic energy stored, L is the inductance of the inductor, and I is the current flowing through the inductor.

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For a series of weak acids, the increase in pKa means that the conjugate bases become more stable.

The term pKa refers to the negative logarithm of the acid dissociation constant. This is a constant that shows the extent to which an acid is dissociated in solution.

As the pKa of a series of  weak acids increases, the conjugate bases become more stable.

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On a construction site, a crane lifts 1000kg of concrete mix to the rooftop at a height of 20 meters in 50 seconds, then the power of the elevator would be 3.924 kilowatts.

The total amount of energy transferred when a force is applied to move an object through some distance.

The work done is the multiplication of applied force with displacement.

The work done by the elevator = mgh

                                                    =1000*9.81*20

                                                    =196200 Joules

The power used by the elevator = work done / time

                                                      =196200 /50

                                                       =3924 watts

Thus, the power used by the elevator would be  3.924 kilowatts.

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The power of elevator is 4,000 w

The time rate of doing work or delivering energy, expressible as the amount of work done W, or energy transferred, divided by the time interval t—or W/t is called power.

Given:

Here, the mass of a concrete lift that can carry by a crane to rooftop =1000 kg,

height =20 m,

time taken by crane to lift concrete mix =50 s

assume, acceleration due to gravity i.e. g =10 m/s²

The formula of power is given by:

power = \(\frac{mass*acceleration due to gravity*height}{time taken}\)

power of elevator =\(\frac{mgh}{t}\)  

= \(\frac{1000*20*10}{50}\)  = 4000 w

Thus, the power of elevator is 4000 w

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Answer:

165.3 cm^3

Explanation: hope this is correct!!

P1 * V1 / T1 = P2 * V2 / T2

P1 = 84.6 kPa

V1 = 215 cm³

T1 = 23.5°C = 23.5 + 273 K = 296.5 K

At STP:

P2 = 101.3 kPa

V2 = ?

T2 = 273 K

The reactions are in order which includes combustion reaction, Hydration reaction, oxidation reaction, and displacement reaction.

a) A combustion reaction is a chemical reaction between a fuel and an oxidant where heat is released. The combustion reaction example is given below. It is a balanced chemical reaction.

2C₃H₆(g) + 9O₂(g) --------> 6CO₂(g) + 6H₂O(g)

b. A hydration reaction is a chemical reaction in which a molecule of water is added to another molecule. Here Aluminum oxide is added to water to form aluminum hydroxide.

4Al₂O3(s) + 6H₂O(l)------> 2Al(OH)3(s)

c. When a metal reacts with oxygen, the metal forms an oxide. Oxide is a compound of metal and oxygen. Here lithium metal reacts with oxygen to form lithium oxide.

2Li(s) + O₂(g)-----> Li₂O(s)

d. A displacement reaction is one in which a more reactive element displaces a less reactive element from a compound. Here Zinc is more reactive than silver, so silver was displaced to form Zinc Nitrate.

Zn(s) + 2AgNO₃(aq) -----> 2Ag(s) + Zn(NO₃)₂(aq)

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Answer:

The entropy increases when sodium chloride is dissolved in water. The ions that were held together in crystalline solid are now moving in all possible directions. Thus entropy increases.

Sodium chloride(NaCl) in water is an endothermic reaction, which means the heat is absorbed. So it will be greater than 0.

Answer:

3.17 grams.

Explanation:

First of all, you need to explain the formula you are going to use. (This does not count as 1 of your 3 sentences).

The formula is

P*V = n*R*T

You know what P and V are on the left

P = 1.2 atmospheres

V = 3.7 Liters

You are looking for n (mols)

On the right, you know what R and T are. So you take the product of R and T and divide into the product of P and V

When you know n, you can use the molar mass to find the actual mass. You can condense this any way you like. I'm more concerned about your understanding.

P*V = 1.2 * 3.7 = 4.44

R*T = 0.0821 * 290 = 23.809

PV/RT = n

4.44 / 23.809 = 0.1865

1 mole of Ammonia gas = 17 grams

0.1865 mol = x                                    Cross multiply

x = 17 * 0.1865

x = 3.17   grams of Ammonia.

4

Answer:

3.17

Explanation:

You can find the mass of the ammonia by using the formula P*V=n*R*T. P=1.2 atmosphere and V= 3.7L. Take the product of R and T and divide to the product of P and V.

P*V=1.2*3.7=4.44

R*T=0.0821*290=23.809

PV/RT=n4.44/23.809=0.1865

X=17*0.1865 ( 1 mole of ammonia gas contains 17 grams)x=3.17 grams of ammonia

When reactants are mixed and heated in an esterification reaction, a liquid product is formed along with other byproducts.

When reactants are mixed and heated in an esterification reaction, a liquid product is formed along with other byproducts. Esterification is a chemical reaction between an alcohol and a carboxylic acid, often catalyzed by an acid catalyst such as sulfuric acid. The reaction produces an ester and water as byproducts.

During the reaction, the alcohol and carboxylic acid are mixed together and heated. The acid catalyst is added to speed up the reaction. As the reaction proceeds, the ester and water are formed. The ester is a liquid, while water is a gas at the reaction temperature.

The liquid product that collects in the side of the apparatus is the ester that is being produced. This liquid can be separated from the reaction mixture and purified using various techniques, such as distillation or extraction. The byproduct water can also be removed by distillation or other means. The ester that is produced can have a wide range of applications, such as in the production of perfumes, flavorings, and plastics.

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Answer:

Prior to his death, Mufasa explains to Simba that “when we die, our bodies become the grass, and the antelope eat the grass, and so we are all connected in the great circle of life” . This is an ecological metaphor that goes beyond the human experience, intertwining the supernatural and physical world.

Explanation:

Answer:

Meaning in some form we all are related some how and that we all have history together

Explanation:

If the chlorine level is too high, it may cause skin and eye irritation, leading to chemical burns in extreme cases. When p is the pH level and c is the chlorine level, the pH level should be between 7.4 and 7.6 pH units, and the chlorine level should be between 1.0 and 1.5 parts per million (PPM).

Pool owners and maintenance professionals must monitor two of the most important water quality indicators in swimming pools: pH and chlorine levels. These two chemicals are crucial to ensuring that the swimming pool remains a safe and healthy place to swim, and that the water is clean and clear. The pH level should be between 7.4 and 7.6 pH units, according to most water test kits.

pH levels outside this range may cause eye and skin irritation, corrosion of the pool’s surface, and an unbalanced pool. If the pH is too low, it will become acidic, causing skin and eye irritation. If the pH is too high, it can cause scaling, resulting in the formation of calcium deposits that are rough on the pool’s surface.

In general, when the pH is too low, the pool’s chlorine level can drop quickly, and when the pH is too high, the chlorine can become less effective. The chlorine level should be between 1.0 and 1.5 parts per million (PPM), according to most water test kits. Chlorine levels outside this range may cause health problems and increase the risk of waterborne illness. When the chlorine level is too low, the pool may become contaminated, resulting in bacterial growth and the spread of disease.

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Answer: North

Explanation:

The correct expression which best reveals the advantage of conducting a comparative investigation over collecting data from the Internet is:

A comparative investigation can provide a wider range of data than can be obtained from the Internet

The correct answer choice is option d.

When making a research or investigation in certain areas such as the ones which involves comparative investigation, one great benefit of it is that it opens our eyes of understanding to get, see and understand information clearly in a function of their differences and similarities.

So therefore, we can now confirm that ease with with the compare the variation and similarities in comparative investigation is one of its advantage over data collection from the website.

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Answer:

False

Explanation:

Answer:

8.1293534120006496

Explanation:

hope this helps

2Na + 2H2O → 2NaOH + H2

The balanced equation

The chemical equation for the given word equation is Ca(OH)\(_2\)(S) + 2HCI(I) → CaCl\(_2\)(aq) + 2H\(_2\)0(1).   Therefore, the correct option is option D.

Chemical equations are symbols or chemical formulas that depict a chemical reaction symbolically. With a plus sign separating the entities in the reactants and products, the reactant objects are listed on the left as well as the result entities are listed on the right.

An arrow indicating the reaction's direction points in the path of the products. The chemical formulas could be mixed, symbolic, or structural. The critical values of a stoichiometric figures are shown as coefficients beside the symbols as well as formulas of the various entities. The chemical equation for the given word equation is Ca(OH)\(_2\)(S) + 2HCI(I) → CaCl\(_2\)(aq) + 2H\(_2\)0(1).  

Therefore, the correct option is option D.

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A home heating system typically includes two other feedback control systems: thermostat control and water heater control.

Thermostat control is a widely used feedback control system in residences to regulate indoor temperature. It consists of a sensor, actuator, and controller. The sensor, usually a thermometer, measures the ambient temperature in the living space. The controller compares the measured temperature with the desired setpoint and determines if heating or cooling is required. The actuator, typically a furnace or air conditioning unit, adjusts the heating or cooling output based on the controller's instructions. Once the ambient temperature reaches the setpoint, the controller signals the actuator to stop heating or cooling, maintaining a comfortable temperature in the residence.

Another common feedback control system found in residences is the water heater control. This system ensures the water temperature is maintained at a desired level. The sensor, often a thermostat, measures the temperature of the water in the heater. The controller compares the measured temperature with the desired setpoint. If the water temperature falls below the setpoint, the controller activates the actuator, such as a heating element, to raise the water temperature. Once the desired temperature is reached, the controller instructs the actuator to stop heating, ensuring a constant supply of hot water for various household needs.

Overall, both thermostat control and water heater control systems in residences rely on sensors to measure relevant parameters, controllers to compare the measured values with desired setpoints, and actuators to adjust the heating or cooling output or water temperature accordingly. These feedback control systems play crucial roles in maintaining comfort and convenience in households.

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Diminished efficiency of the sodium-potassium pump due to hypoxia may be associated with hydropic change

Sodium is a chemical element with the symbol Na and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal and belongs to group 1 of the periodic table. Its only stable isotope is Na. Free metals do not exist in nature and must be made from compounds.

Summary. Table salt is a combination of two minerals, sodium, and chloride. Your body needs some sodium to function properly. Helps nerves and muscles work. It also helps maintain proper water balance in the body. The kidneys control the amount of sodium in the body.

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Answer: Together, the number of protons and the number of neutrons determine an element's mass number: mass number = protons + neutrons.

Explanation:

Answer:

-1464 kJ/mol

Explanation:

The balanced equation for the reaction is given as;

C2H4(g)+3O2(g)→2CO2(g)+2H2O(l) ΔH∘1=?

The enthalpy of the reaction is given by the equation;

Enthalpy of reaction = Enthalpy of products - Enthalpy of reactants

Products:

2CO2(g)+2H2O(l)

Enthalpy of Products = 2 (−394) + 2(−286)

Enthalpy of Products = -1360 kJ/mol

Reactants:

C2H4(g)+3O2(g)

Enthalpy of Reactants = 2 (52) + 3(0)

Enthalpy of Reactants = 104 kJ/mol

Enthalpy of Reaction =  -1360 - 104 = -1464 kJ/mol

The characteristics and the type of molecular bond they describe:

1. Bonds found in Halite (between Na⁺ and Cl⁻): Ionic bond

2. Bonds found between Si and O in the Si-O tetrahedron: Covalent bond

3. Bonds inside the water molecule (between the H and O): Covalent bond

4. Bonds that exist between two water molecules: Hydrogen bond

5. Strongest bond type: Covalent bond

6. Weakest bond type: Van der Waals bond

7. Bonds that are used by water to dissolve salt: Ionic bond

The ionic bond is a type of molecular bond found in halite (between Na⁺ and Cl⁻). The Si-O tetrahedron is held together by a covalent bond. The bond inside the water molecule (between the H and O) is also a covalent bond. The hydrogen bond is the type of bond that exists between two water molecules. The covalent bond is the strongest bond type, while the van der Waals bond is the weakest bond type. Water uses the ionic bond to dissolve the salt.

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The organic compounds that are divided into two types, simple and complex, are called carbohydrates.

Carbohydrates are diveded into twy types: simple and complex (starches, fiber, glycogen).

Simple carbohydrates are made of one (monosaccaharides) or two sugar units.

Complex carbohydrates are made up of many sugar units.

For example, glucose (C₆H₁₂O₆) is a simple carbohydrate.

Glucose is chemical compound composed of six carbon atoms, twelve hydrogen atoms and six oxygen atoms.

Starch is a polymeric carbohydrate consisting of a large number of glucose units bonded by glycosidic bond. Starch is a white, tasteless and odorless powder that is insoluble in cold water or alcohol.

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Among the bond ratings provided, Baa1 has the highest yield. The bond ratings provided are based on the creditworthiness and risk associated with the issuer.

Generally, higher-yielding bonds indicate higher risk, which is reflected in lower credit ratings. Baa2, Baa3, and BBB all have lower credit ratings compared to Baa1, indicating a higher level of risk and, therefore, potentially higher yields. Key Learnings. Junk bonds, often known as high-yield bonds, are corporate financial securities that provide interest rates above those of investment-grade bonds. Low credit ratings, such as below BBB- from Standard & Poor's and Fitch or below Baa3 from Moody's, are typical of high-yield bonds.

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To calculate the concentration of molecular, deprotonated, and protonated species in a water tank solution, we can use the pH and pKa values provided.

First, let's understand the relationship between pH and pKa. The pKa is a measure of the acidity of a compound. It tells us the pH at which the compound is half dissociated. A compound with a pKa lower than the pH is mostly in its protonated form, while a compound with a pKa higher than the pH is mostly in its deprotonated form.

In this case, the pH is 6.5 and the pKa is 1.87. The pH is higher than the pKa, so we expect the compound to be mostly in its deprotonated form.

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Your limiting reagent will be copper (II) chloride. The mole ratio is the most crucial tool you'll have to tackle this problem, or any other stoichiometry problem, for that matter.

Keep in mind that in order to make 3 moles of copper from 3 moles of copper (II) chloride, you need 2 moles of aluminum. Unbalanced reaction: Al(s)+HCl(aq) AlCl3(aq)+H2(g). Cl. Balance On the product side there are three Cl atoms and on the reactant side there is one. There is only one hydrogen atom on the reactant side and two on the product side of the reaction Mg + HCl MgCl 2 + H 2. The equation is therefore unbalanced.

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The empirical and molecular formulas of benzene is C6H6. Six carbon atoms make up the closed ring benzene, which is joined by alternating single and double bonds.

The simplest whole-number ratio of the various atoms in a compound is represented by an empirical formula. The precise number of various atom types present in a compound's molecule is indicated by the molecular formula.

The chemical compound benzene has the molecular formula C6H6 and is an organic chemical. Six carbon atoms are connected in a planar ring to form the benzene molecule, and one hydrogen atom is attached to each one. Benzene is categorized as a hydrocarbon because it solely has carbon and hydrogen atoms.

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Answer: There are 2.41 * 102 molecules in 4.00 moles of glucose.

Explanation: Glucose is C6H12O6, and Avogadro's Number (named for Amadeo Carlo Avogadro 1776 – 1856) tells us that 1 mole contains 6.022 x 10^23 molecules. So, 4.0 moles contains 4 x 6.022 x 10^23 = 2.409 x 10^24 molecules.

Answer:

Fibre , it is a long thin strand or something like thread of material.

Fabric, it is a cloth material made by weaving or knitting threads together.

Explanation:

1. Fiber: is a thin thread of a natural or artificial substance, especially on that is use to make cloth or rope.

2.Fabric is a cloth or other materials produce by weaving together cotton, nylon, wool, silk or other threads. Fabric are used for making things such as clothes, curtains and sheets.