Which of the following best describes isotopes?


An element with the same number of neutrons, but a different number of protons.


An element with the same number of protons, but a different number of electrons.


An element with the same number of electrons, but a different number of neutrons


An element with the same number of protons, but a different number of neutrons

Answer:

C) F

Explanation:

Valence electrons are the electrons present in the outermost shell of an atom and have the highest energy level of an atom whereas electrons at ground state or lower orbitals have less potential energy.

This is so because orbitals nearby nucleus are strongly bonded with the atomic nucleus and have less energy than an outermost shell.

So, the potential energy states of an atom depend on the number of orbitals. In the given options fluorine with atomic number 9 has less number of orbitals that is 2 orbitals and valence electrons will be present in second orbitals, so fluorine will have the lowest average potential energy states.

Hence, the correct option is "C) F".

The enthalpy of combustion for 1kg of urea is -1223525.84 J/mol.

Urea is a compound that is used in fertilizers and in some plastics.The enthalpy of combustion for urea is the amount of energy that is released when urea is burned. In order to calculate the enthalpy of combustion for 1kg of urea, we need to use the information that is provided to us in the question. Let us start by writing down the balanced equation for the combustion of urea: CO(NH2)2 + 3/2 O2 → CO2 + 2H2O + N2
The balanced equation shows that 1 mole of urea reacts with 1.5 moles of oxygen gas to produce 1 mole of carbon dioxide, 2 moles of water, and 1 mole of nitrogen gas. The enthalpy change for this reaction is equal to the amount of energy that is released when 1 mole of urea is burned.
The heat of combustion (ΔHc) of urea is -632.6 kJ/mol. This means that 632.6 kJ of energy is released when 1 mole of urea is burned. We know that 12g of urea raised the temperature of water by 30°C. We can use this information to calculate the amount of energy that was released when 12g of urea was burned.
The specific heat capacity of water is 4.18 J/g°C. This means that it takes 4.18 J of energy to raise the temperature of 1 gram of water by 1°C. Therefore, it takes 4.18 x 1000 = 4180 J of energy to raise the temperature of 1 kg of water by 1°C.
We know that 12g of urea raised the temperature of water by 30°C. Therefore, the amount of energy that was released when 12g of urea was burned is:
Energy = mass x specific heat capacity x temperature change
Energy = 0.012 kg x 4180 J/kg°C x 30°C
Energy = 1497.6 J
We can now use this information to calculate the enthalpy of combustion for 1kg of urea:
Enthalpy of combustion = energy released / moles of urea burned
Enthalpy of combustion = 1497.6 J / (0.012 kg / 60.06 g/mol)
Enthalpy of combustion = - 1223525.84 J/mol
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Answer:

here is the answer

Explanation:

ketone is the answer

Answer:

The mass of the solid sample is 4.442 g (5.853 g - 1.411 g).

Explanation:

The mass of the solid sample can be determined by subtracting the mass of the weigh boat from the mass of the weigh boat and sample. This is because the weigh boat is a constant and known value, and it is used as a reference to measure the mass of the sample. To find the mass of the sample, we use the formula:

Mass of sample = Mass of weigh boat and sample - Mass of weigh boat

In this scenario:

Mass of sample = 5.853 g - 1.411 g = 4.442 g

Therefore, the mass of the solid sample is 4.442 g.

Answer:

Please find the complete solution in attached file.

Explanation:

Periodic law is the the properties of the elements that repeat in a regular way as the atomic numbers increase.

Periodic chart organized collection of all chemical elements arranged roughly according to increasing atomic weight. The periodic recurrence of several features in the elements was originally identified by Dmitry I. Mendeleyev in 1869.

1. This is a vertical arrangement of elements in the periodic table   group

2. This is a horizontal arrangement of elements in the periodic table   period

3. The properties of the elements repeat in a regular way as the atomic numbers increase periodic law

4. Element 19 begins this arrangement in the periodic table period

5. The chemical properties of elements 12, 20, and 38 demonstrate this principle.  periodic law

Therefore, periodic law is the the properties of the elements that repeat in a regular way as the atomic numbers increase.

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The final broth temperature will be approximately 38.4°C.

When mixing two substances with different temperatures, we can use the principle of conservation of energy. The energy lost by the hot substance (broth) is equal to the energy gained by the cold substance (water), assuming no energy is lost to the surroundings. This can be expressed using the equation:

Q_lost = Q_gained

The energy lost by the broth can be calculated using the formula:

Q_lost = m_broth * c_broth * (T_final - T_initial)

where m_broth is the mass of the broth, c_broth is its specific heat capacity, T_final is the final temperature, and T_initial is the initial temperature of the broth.

Similarly, the energy gained by the water can be calculated using:

Q_gained = m_water * c_water * (T_final - T_initial)

Since the two substances reach thermal equilibrium, we can set Q_lost equal to Q_gained:

m_broth * c_broth * (T_final - T_initial) = m_water * c_water * (T_final - T_initial)

Plugging in the given values and solving for T_final, we find that the final temperature of the broth is approximately 38.4°C.

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The electronegativity difference between Li (Li: 0.98) and F (F: 3.98) is 3.00.

Electronegativity difference is a measure of the relative tendency of an atom in a chemical bond to attract electrons to itself. It is defined as the difference in electronegativity between two atoms in a chemical bond.

A low electronegativity difference indicates that the bond is nonpolar, with both atoms having a similar attraction to the electrons. The difference between the electronegativity of Li and F is large, indicating that the bond between them is highly polar. This means that the F atom has a greater attraction for electrons in a chemical bond than the Li atom, which results in a polar covalent bond.

So subtracting 0.98 of lithium from 3.98 Fluorine to get 3.00 electronegativity difference.

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The complete question is:

What is the Electronegativity difference between Li and F?

This representation suggests that the element is phosphorus (P) with a mass number of 30, which is incorrect. The correct mass number for phosphorus is approximately 30.97. The incorrect representation for a neutral atom is 36Li

To determine the correct representation for a neutral atom, we need to consider the atomic number (Z) and mass number (A) of the element. The atomic number represents the number of protons in the nucleus, while the mass number represents the sum of protons and neutrons.

Let's analyze the given representations:

36Li:

This representation suggests that the element is lithium (Li) with a mass number of 36, which is incorrect. The correct mass number for lithium is approximately 6.94.

613C:

This representation suggests that the element is carbon (C) with a mass number of 13, which is correct. Carbon has different isotopes, and 13C represents one of its stable isotopes.

3063Cu:

This representation suggests that the element is copper (Cu) with a mass number of 63, which is correct. Copper has different isotopes, and 63Cu represents one of its stable isotopes.

1530P:

This representation suggests that the element is phosphorus (P) with a mass number of 30, which is incorrect. The correct mass number for phosphorus is approximately 30.97.

Therefore, the incorrect representation for a neutral atom is 36Li, as it does not match the known properties of lithium.

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Answer:

Anyone got the answers

Explanation:

Answer: A

Explanation: just do as I say

Answer:

A Elements

Explanation:

The substances on the periodic table are examples of elements.

An element is a distinct substance that cannot be split-up into simpler substances. Such substances consists of only one kind of atom.

There are over one hundred elements that are known to date.

Answer: 9084355.951 L  if need in correct sig figs answer is

9.08 X 10^6 L

Explanation:

Ideal gas law  PV=nRT  = V=nrt/P

R= 62.44

n=0.511

T= 513

P= 555

V= 0.511 X 62.44 X 513 / 555

Answer:

Explanation:

The density of a substance can be found by using the formula

\(density = \frac{mass}{volume} \\\)

From the question we have

\(density = \frac{35.3}{31.7} \\ = 1.113564\)

We have the final answer as

Hope this helps you

A 70 piece of metal at 120 C is dropped into a kilometer with 150 g of 30C water the final temperature of the water and little changes 35c,  0.385 J/g°c is the specific heat of the metal​.

The amount of heat needed to raise a substance's temperature by one degree Celsius in one gramme, also known as specific heat. Typically, calories and joules per gramme per degree Celsius are used as a measure of specific heat.

In the 18th century, the Scottish researcher Joseph Black found that equivalent masses of various substances required varying quantities of heat to bring them across the same temperature range. Based on this finding.

cm = (0.15 kg x 4.18 J/gCx (35C - 30C)) / (70 pieces x 0.1 kg/piece x (120C - 35C))

cm = 0.385 J/g°c

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Sedimentation, filtration, and coagulation are the treatments that will help remove contaminants from minerals or from the pipes carrying water from a source.

Sedimentation is a process in which suspended particles settle out of water. It is one of the most basic techniques for removing particles from water. As particles settle, they become trapped in the bottom of a container or settle to the ground in an outdoor setting

Filtration is a method of removing particles from a fluid. It is a physical or chemical separation method that separates solids from fluids (liquids or gases) by adding a medium through which only the fluid can pass.

Coagulation is the process of using chemicals to remove contaminants from water. By creating a chemical reaction, coagulation destabilizes particles and causes them to clump together. This helps to remove the contaminants from the water.

Disinfection is the process of eliminating or destroying pathogens that cause infection. Disinfection eliminates harmful microorganisms by destroying or inactivating them. The disinfectant is a chemical or physical agent that is used to destroy or inactivate harmful microorganisms.

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The balanced equation for the reaction of guanidine with water is: (NH2)2CNH (aq) + H2O (l) ⇌ (NH2)2CNH2+ (aq) + OH- (aq).

The Kb expression for this reaction is: Kb = [OH-] [(NH2)2CNH2+] / [(NH2)2CNH]

In this reaction, guanidine acts as a Brønsted-Lowry base by accepting a proton from water to form the conjugate acid (NH2)2CNH2+ and the hydroxide ion (OH-).

The Kb expression reflects the equilibrium between the reactants and products, with the concentrations of the products in the numerator and the concentration of the base in the denominator.

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Answer:

Explanation:

ok

Potash alum, represented by the chemical formula KAl(SO4)2·12H2O, is a double salt because it consists of two different salts, potassium sulfate (K2SO4) and aluminum sulfate (Al2(SO4)3), combined together. It forms a unique crystalline structure with 12 water molecules incorporated in its composition.

Potash alum is a type of alum that is commonly used in dyeing and water purification applications. The chemical formula for alum is KAl(SO4)2·12H2O.

The term "double salt" refers to the fact that the compound is made up of two different types of ions that are combined together.
In the case of potash alum, the two different types of ions are potassium ions (K+) and aluminum ions (Al3+). These two ions are combined together in a 1:1 ratio to form a complex ion, KAl(SO4)2, which is then combined with 12 water molecules to form the final compound, KAl(SO4)2·12H2O.
The term "double salt" is used to describe this type of compound because it contains two different types of cations (positive ions) that are combined together to form a single crystal lattice structure.

The two different cations are held together by ionic bonds, which are relatively strong and help to give the compound its characteristic properties.
Potash alum is a particularly useful compound because it has a number of important properties that make it useful in a variety of applications.

For example, it is highly soluble in water, which makes it a good choice for use in water purification applications.

It is also relatively stable and non-toxic, which makes it safe to use in a variety of different settings.

Finally, it has a number of useful physical properties, such as its ability to form crystals that are highly reflective and have a characteristic octahedral shape.

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Answer:

the answer to this question is A H202

The substances sodium carbonate, magnesium sulphate and ammonium chloride are all ionizes in their solution. The ions of sodium carbonate is Na⁺and CO₃ ²⁻ and the ions of MgSO₄ is Mg²⁺ and SO₄²⁻ and that of NH₄Cl is NH4+ and Cl⁻.

Ionic compounds are formed by between metals and non metals. The metals are all electropositive and they can donate their valence electrons to the electronegative nonmetals.

Sodium carbonate is formed by the donation of one electron from the sodium metal to the carbonate ion and the ions formed when it is dissolved in water are Na⁺and CO₃ ²⁻.

Similarly, magnesium sulphate is formed by losing two electrons from Mg and it gains two positive charge and sulphate ions accept those electrons to have two negative charges. Thus the ions are Mg²⁺ and SO₄²⁻.

In the same fashion ammonium chloride, NH₄Cl is ionised into NH4+ and Cl⁻.

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Answer:

D produce energy

Explanation:

Mitochondria are membrane-bound cell organelles (mitochondrion, singular) that generate most of the chemical energy needed to power the cell's biochemical reactions.

Answer:produce energy

Explanation:

The experimental yield is 2.9 g, the theoretical yield is 2.96 g, and the percent yield is 97.97%.

How to find the experimental yield, theoretical yield and Percent yield?

To find the experimental yield, we need to determine the weight of copper chloride (CuCl) obtained from the reaction. We can calculate this by subtracting the weight of the watch glass and filter paper from the weight of the watch glass, filter paper, and CuCl precipitate:

Weight of CuCl = (Weight of Watch Glass + Filter Paper + CuCl Precipitate) - (Weight of Watch Glass and Filter Paper)

Weight of CuCl = 13.4 g - 10.5 g

Weight of CuCl = 2.9 g

To find the theoretical yield, we need to calculate the amount of copper that should be produced based on the reaction stoichiometry. The balanced chemical equation for the reaction between copper and nitric acid is:

Cu + 4HNO3 → Cu(NO3)2 + 2NO2 + 2H2O

From the equation, we can see that one mole of copper reacts with four moles of nitric acid to produce one mole of copper(II) nitrate (Cu(NO3)2). The molar mass of copper is 63.55 g/mol, so the amount of copper used in the reaction is:

Amount of Cu = Weight of Cu / Molar mass of Cu

Amount of Cu = 1.034 g / 63.55 g/mol

Amount of Cu = 0.016 mol

Since one mole of copper produces one mole of copper(II) nitrate, the theoretical yield of copper(II) nitrate is also 0.016 mol.

The theoretical yield of copper(II) nitrate is:

Theoretical yield = Amount of Cu(NO3)2 x Molar mass of Cu(NO3)2

Theoretical yield = 0.016 mol x 187.57 g/mol

Theoretical yield = 2.96 g

Finally, we can calculate the percent yield using the formula:

Percent yield = (Experimental yield / Theoretical yield) x 100%

Plugging in the values we calculated, we get:

Percent yield = (2.9 g / 2.96 g) x 100%

Percent yield = 97.97%

Therefore, the experimental yield is 2.9 g, the theoretical yield is 2.96 g, and the percent yield is 97.97%.

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Answer:

Plant cells contain two organelles that are essential for their functioning. These are the chloroplasts and the vacuoles. The chloroplasts are the organelles responsible for photosynthesis, which involves converting light energy from the sun into chemical energy in the form of glucose. Without chloroplasts, plants would not be able to produce their own food. The vacuoles are large organelles filled with fluid that serve to store nutrients and other materials. Vacuoles also help to maintain the turgor pressure of the cell, which is the pressure that helps to keep the cell rigid and prevents it from collapsing. Without vacuoles, plant cells would not be able to remain rigid and would collapse, leading to the death of the plant.

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Answer:

0.00735°C

Explanation:

By seeing the question, we can see the elevation in boiling point with addition of BaCl₂ in water

⠀

\( \textsf {While} \: \sf {\Delta T_b} \: \textsf{expression is used} \\ \textsf {for elevation of boiling point}\)

⠀

⠀

The elevation in boiling point is a phenomenon in which there is increase in boiling point in solution, when the particular type of solute is added to pure solvent.

⠀

⠀

\( \sf \large \underline{The \: formula \: to \: be \: used \: in \: this \: question \: is} \\ \boxed{T_b = i \times K_b \times m}\)

⠀

⠀

Where 'i' is van't hoff factor which represents the ratio of observed osmotic pressure and the value to be expected.

and 'i' is 3 (as given in the question)

⠀

'Kb' is molal boiling point constant. And it's value is 0.51°C/mol(given in question)

⠀

'm' represent the molality of solution. Molatity is no. of moles of solution present in 1kg of solution.

⠀

⠀

To find molality, we have to divide no. of moles of solute by weight of solution

⠀

While first we need to no. of moles

\( \sf \implies no. \: of \: moles = \frac{weight \: of \: solute}{molar \: mass \: of \: solute} \\ \\ \implies \sf no. \: of \: moles = \frac{1.5}{208.23} \\ \\ \sf \implies no. \: of \: moles = 0.0072 \)

⠀

⠀

Now, we will find molality

⠀

\( \sf \hookrightarrow molality = \frac{no.\: of \: moles}{weight \: of \: solution} \\ \\ \sf \hookrightarrow molality = \frac{0.072}{1.5} \\ \\ \sf \hookrightarrow molality = 0.048 \: mol {kg}^{ - 1} \)

⠀

⠀

\( \textsf{ \large{ \underline{Now substituting the required values}}} \)

⠀

\( \sf \longmapsto \Delta T_b = 3 \times 0.51 \times 0.0048 \\ \\ \\ \boxed{ \tt{ \longmapsto \Delta T_b =0.00735{ \degree}C}}\)

⠀

⠀

⠀

Henceforth, the change in boiling point is 0.00735°C.

Answer:

The uncertainty principle is one of the most famous (and probably misunderstood) ideas in physics. It tells us that there is a fuzziness in nature, a fundamental limit to what we can know about the behavior of quantum particles and, therefore, the smallest scales of nature.

The element that has chemical properties most similar to sodium is d. rubidium.

What is rubidium?

Rubidium is in the same group (group 1) as sodium in the periodic table and has similar chemical properties, such as reactivity with water and the tendency to form ionic compounds with halogens. Magnesium, oxygen, and phosphorus are not in the same group as sodium and have different chemical properties.

What is periodic table?

The periodic table is a tabular display of all known chemical elements, arranged according to their atomic structure and properties. It is arranged in rows and columns, with elements placed in order of increasing atomic number, which is the number of protons in an atom's nucleus. The periodic table is a powerful tool for predicting the chemical behavior of elements and for understanding the relationships between different elements. It is used extensively in chemistry, physics, and other sciences to help understand the properties and behavior of different elements, and to guide research and development in many different fields.

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the enthalpy of reaction for HCl(g) + NaNO₂(s) → HNO₂(l) + NaCl(s) 2NaCl(s) + H₂O(l) → 2HCl(g) + Na₂O(s) ∆H° = -507.1 kJ/mol NO(g) + NO₂(g) + Na₂O(s) → 2NaNO₂(s) ∆H° = -427.0 kJ/mol NO(g) + NO₂(g) → N₂O(g) + O₂(g) ∆H° = -43.01 kJ/mol 2HNO₂(l) → N₂O(g) + O₂(g) + H₂O(l) ∆H° = +34.02 kJ/mol the enthalpy of reaction for the given reaction is -39.1 kJ/mol.

We can use the given reactions and their enthalpies to find the enthalpy of reaction for the given equation.

The given equation is:

HCl(g) + NaNO₂(s) → HNO₂(l) + NaCl(s)

We can break down this reaction into several steps using the given reactions as follows:

Na₂O(s) + 2HCl(g) → 2NaCl(s) + H₂O(l) (reverse of the given reaction)

∆H° = +507.1 kJ/mol (reverse the sign of given reaction)

2NaCl(s) + H₂O(l) → Na₂O(s) + 2HCl(g)

∆H° = -507.1 kJ/mol (given reaction)

NO(g) + NO₂(g) + Na₂O(s) → 2NaNO₂(s)

∆H° = -427.0 kJ/mol (given reaction)

2HNO₂(l) → N₂O(g) + O₂(g) + H₂O(l)

∆H° = +34.02 kJ/mol (given reaction)

NO(g) + NO₂(g) → N₂O(g) + O₂(g)

∆H° = -43.01 kJ/mol (given reaction)

Now, we can add these equations and their enthalpies to get the overall enthalpy of the given reaction:

HCl(g) + NaNO₂(s) → HNO₂(l) + NaCl(s)

H₂O(l) + 2NaCl(s) → Na₂O(s) + 2HCl(g) ∆H° = -507.1 kJ/mol

Na₂O(s) + NO(g) + NO₂(g) → 2NaNO₂(s) ∆H° = -427.0 kJ/mol

2HNO₂(l) → N₂O(g) + O₂(g) + H₂O(l) ∆H° = +34.02 kJ/mol

NO(g) + NO₂(g) → N₂O(g) + O₂(g) ∆H° = -43.01 kJ/mol

HCl(g) + NaNO₂(s) → HNO₂(l) + NaCl(s) ∆H° = -39.1 kJ/mol

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First part: semiconducting

Second part: tellurium

Answer:

the empirical (lowest raios) is

C2H4Cl    

Explanation:

A compound is known to consist solely of carbon, hydrogen, and chlorine. Through elemental analysis, it was determined that the compound is composed of 24.27% carbon.

What is the empirical formula of this compound?

the compound has ONLY C, H, and Cl

the % Cl  = 100% - 24.27% -4.03% = 71.7%

in 100 gm, there are 71.7 gm Cl, 24.27 gm C, and 4.03 gm H

the number of moles are Cl=71.7/70.91 =1.01= ~ 1

                                          C = 24.27/12.0 = 2.02 =~ 2

                                           H = 403/1.01 = 3.97 =~   4

so   the empirical (lowest raios) is

C2H4Cl      

It is the simplest whole number ration of elements in a compound. Molecular formula is n times the empirical formula where n is integers 1,2,... the empirical formula is CH₂O

An empirical formula gives the proportion of the element that is present in a compound does not give information about the actual number or the arrangements of the atoms. We can find empirical formula or molecular formula if percentage of each element in that compound is given.

Find Number of gram atoms in compound and Divide by smallest Number of gram atoms in compound

C=24.27%÷12=2.02÷2=1

H=4.03%÷1=4.03÷2=2

Cl=71.7%÷35.4=2.02÷2=1

The atomic ratio is 2:4:2

Whole number ratio C:H:Cl is 1:2:1

Empirical formula corresponding to this whole number is CH₂O

Thus the empirical formula is CH₂O

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