what is the total number of moles represented by 20 grams of CACO3

A. 0.1
B. 0.2
C. 1
D. 2

Answer:

Explanation:

A polar covalent bond is the result of uneven distribution of the electrons involved in the covalent bond.

The polar character of a covalent bond is determined by the difference in the electronegativities of the atoms bonded.

The higher the electronegativity difference of the two bonded atoms the more polar the covalent bond is.

Then, you need to find and compare the electronegativies of the atoms bonded.

This is the list of electronetativities of every atom in the question:

Using that list you can do these calculations:

Bond           Electronegativity difference

a) B–H          2.20 - 2.04 = 0.16

b) N–H         3.04 - 2.20 = 0.84

c) P–H          2.20 - 2.19 = 0.01

d) Al–H        2.20 - 1.61 = 0.59

e) C–H         2.55 - 2.20 = 0.35

Thus, the greatest electronegativity difference is that of N - H, 0.84, which indicates that this is the most polar bond from the choices.

The most polar bond among the given options is N-H.

The most polar bond among the given options is N–H.

The polarity of a bond is determined by the difference in electronegativity between the two atoms involved. Nitrogen (N) has a higher electronegativity compared to the other elements in the choices, and hydrogen (H) has a lower electronegativity. The greater the electronegativity difference, the more polar the bond.

For example, in a N–H bond, nitrogen attracts the shared electrons more strongly than hydrogen, resulting in a partial negative charge on nitrogen and a partial positive charge on hydrogen.

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Answer:

The correct answer is option C

Explanation:

Pure water at 25°C self-ionizes to form an equilibrium in which. Option C is correct. This is further explained below.

Generally, ionization is simply defined as any process that turns electrically neutral atoms or molecules into electrically charged ones.

In conclusion, At 25°C, pure water self-ionizes to establish an equilibrium in which

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Answer:

= 25 ppm

Explanation:

Given; a sample size of 2000 g contained 0.050 g DDT

It means, 2000 mL sample contained 50 mg DDT

Therefore in ppm we get;

= 50 mg/ 2 L

= 25 mg/L

= 25 ppm

The concentration of DDT in your sample is calculated by dividing the mass of DDT by the total mass and multiplying by 1,000,000. Using your provided values, the DDT concentration is 25 parts per million (PPM).

In the context of your question, you want to know the concentration of DDT in a sample size of 2000 g which contains 0.050 g of DDT in terms of parts per million (PPM). PPM is a unit typically used to express concentrations of pollutants and other trace contaminants in similar low concentration scenarios.

To calculate the concentration in PPM, the formula is quite straightforward. You divide the mass of the contaminant by the total mass of the sample, then multiply the result by 1,000,000.

Using your values:

(mass of DDT / total mass) * 1,000,000 = (0.050g / 2000g) * 1,000,000 = 25 ppm.

This means that there are 25 parts of DDT per every 1,000,000 parts of the sample.

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Answer: its A

Explanation:

Answer: Option A

Explanation:

One gene one enzyme hypothesis was proposed by George Wells Beadle in which he stated that one gene directly affects the production of the  single enzyme.

This consequently affects the individual step in the whole metabolic pathway.  

So, a mutation in the single gene will lead to the production of the faulty protein. The step of the metabolism will be affected in which the faulty enzyme will participate.

Answer: 21.9

Explanation:

I got it right

Answer:

See below  

Explanation:

A. False. Alpha radiation is more damaging to the cell than beta radiation.

B. True. Beta radiation is less damaging, but it has greater penetrating power, so it can damage more cells.

C. True. Beta particles have greater penetrating power than alpha particles.

D. False. Beta particles are electrons. Alpha particles are much larger helium nuclei.

Answer:

False

True

True

False

Explanation:

Option A is False. Alpha radiation transfers more energy to the absorbing material than a beta particle. So alpha rays damage more cells than beta radiation.  

Option B is True. Beta cells are more penetrating than alpha cells, hence they wreck more havoc.  

Option C is True. Having smaller mass beta particles can travel farther, they penetrate through the skin and are absorbed by the body tissues. Alpha particles are heaver and don’t go past the skin cells.  

Option D is False. Beta particles are fast moving electrons with a negative charge where alpha particles are made up of two neutrons and two protons and so it is a +2 charged helium nucleus.  

Answer: Electrons orbit the nucleus

Final answer:

In an atom, electrons are not found in the nucleus but in orbitals around it. These orbitals represent regions of high probability for the electron's location, and their shapes are determined by quantum mechanical wave functions.

Explanation:

The component of an atom that you would not expect to find in the nucleus but might be orbiting around it is the electron. Electrons are found in orbitals, which are regions in space surrounding the nucleus where they are likely to be located. Unlike the Bohr model's simple orbits, these areas are defined by mathematical equations from quantum mechanics, reflecting the dual wave-particle nature of electrons.

The structure of an atom includes a central nucleus, composed of protons and neutrons, which houses most of the atom's mass, with electrons distributed in the space surrounding the nucleus.

Answer:

Energy was released when the sodium and hydroxide ions formed new bonds with the water.

Explanation:

Answer:

The lattice enthalpy of sodium hydroxide is less than the sum of hydration enthalpies of hydroxide ions and sodium ions.

Explanation:

Lattice enthalpy is defined as heat energy required to break 1 mole of crystal lattice.

Hydration enthalpy is defined as amount energy released when 1 mole of ions undergo hydration (surrounding of water molecules).It is always negative.

Enthalpy of solution = Lattice enthalpy + hydration enthalpy

Reaction between sodium hydroxide and water is an example of an exothermic reaction. During this process sodium hydroxide dissociates into sodium ions and hydroxide ions into the water.

The rise in temperature is due to hydration enthalpy of hydroxide ions and sodium ions is greater than that of the lattice enthalpy of the sodium hydroxide. This is the reason behind the warmth of the sodium hydroxide solution.

Answer:

The correct answer from the choices, which are included in the comments section, is:

Explanation:

Let's go through every choice from the list:

A. Easier to understand:

Incorrect.

Quantum model is not quite easy to understand. On the contrary, it is complex and quite hard to understand.

John Dalton's model was the first scientific model of the atom. It depicted the atom as indivisible, extremely tiny particles that constitute all matter.

Many facts were discovered later: the atom is not indivisible, there are some subatomic particles (electrons, protons and neutrons), the electrons are not in fixed positions (orbits) that were progresively explained by new models: J.J Thomson's model, Ernest Rutherford's model, Niels Bohr's model, and, the last and current one, the quantum model/

So. it is not easier to understand but more complete.

b. is a more recent theory

Incorrect.

As said, John Dalton's theory was the first scientific theory of the atom. It was developed in the first half of XIX century. It is, definetly, no a more recent theory. Modern-day quantum model is the most recent theory of the atom.

C. Can be represented in two dimensions

Incorrect.

Modern-day quantum model represents the electrons in a 3-D arrangement around the atom's nucleus, like a "cloud" without definite size. Two dimensional representation is not a characteristic that defines how the modern-day quantum model of the atom is better than other models.

D. Answers many questions about atoms

Correct. Indeed, every model of the atom after John Dalton's model explains more facts about the atoms: J.J Thomson's explained that the negative charges are particles inside the atom (electrons); Ernest Rutherford's model explained the existence of the nucleus with protons, while the electrons are surrounding the atom; Bohrs model explained that the electrons cannot decay into the atoms' nuclei, because they can only have certain enery levels; and the modern-day quantum model explains much more facts than any previous one, specially about the behaviour of the subatomic particles.

Answer:

c. triple bond

Explanation:

The shortest and strongest covalent bond is the triple bond. It involves the sharing of three pairs of electrons between two atoms, making it stronger and shorter than single and double bonds. An ionic bond is a different kind of bonding involving the transfer of electrons.

In terms of covalent bonds, the triple bond is both the shortest and the strongest. Covalent bonds are a category of chemical bonding where two atoms share one or more electron pairs. Single bonds are longer and weaker since they involve the sharing of only one pair of electrons. Double bonds involve two pairs and are shorter and stronger. Triple bonds, such as those found in a nitrogen molecule (N2), are the shortest and strongest since they involve the sharing of three pairs of electrons. The ionic bond is not a type of covalent bond, it's a completely different kind of bonding which involves the transfer of electrons from one atom to another, not sharing.

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Answer: Option (B) is the correct answer.

Explanation:

Entropy is the measure of randomness present within the molecules of a substance.

When entropy of a reaction has a positive sign then it means there is an increase in the entropy. On the other hand, when entropy of a reaction has a negative sign then it means there is a decrease in entropy.

As, entropy change = entropy of products - entropy of reactants

And, larger is the value of entropy more will be the number of microstates.

When entropy is negative then entropy of products is less than the entropy of reactants.

This also means that products have small number of available energy microstates than reactants.

Thus, we can conclude that a negative change in entropy indicates that the products have a smaller number of available energy microstates than the reactants.

Answer:

A negative charge of entropy indicates that the product has a smaller number of available energy microstates than the reactants.

Explanation:

Entropy can be defined as the thermodynamic property of the system associated with the randomness of the molecules.  The energy of entropy is represented as the mathematical flow for the availability of the reactants and products.

When the entropy has a negative charge, this indicates that there is a decrease in the entropy of the system.

A positive charge of entropy indicates the increase in the energy of the system. This indicates that there is a greater number of available microstates for the product.

With a negative charge, there is a decrease i.e. the available energy microstates are smaller for the product stating the product has lesser energy as compared to the reactants.

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D) mass of snake after feeding is equal to orginal mass of snake plus mouse since the mass is conserved

The law of conservation for the feeding of mice by snake by Dr. Martin states the mass of snake after feeding being equivalent to the mass of snake before plus the mass of mice. Hence, option D is correct.

The law of conservation is given as the state in which the quantity can neither be created nor  be destroyed.

The mass as the physical quantity in the chemical reaction founds to be conserved and not lost.

Thus, for the consumption of the mice by the snake according to the law of conservation stated by Dr. Martin, that the mass of snake after feeding mice will be the sum of the mass of snake before and the mass of mice. Thus, option D is correct.

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Answer:

The right word to fill the blank space is GREATER THAN.

Explanation:

In nature, heat in form of temperature is usually transfer from the region of higher temperature to the region of lower temperature. Thus, for heat to be transfer from one substance to another one, the temperature will flow from the body with the higher temperature to that which has a lower temperature, the substance that is giving out the heat must have a higher temperature.  

Explanation:

When two substances of different temperature are in contact with each other then heat will flow from hot object to cold object until a thermal equilibrium is maintained between them.

Kinetic energy is the energy obtained due to the motion of an object is known as kinetic energy. Total kinetic energy of all the particles present in a system is known as average kinetic energy.

Thus, we can conclude that when two samples of carbon come into contact. Heat will transfer from Sample A to Sample B if the average kinetic energy of Sample A's atoms is greater than the average kinetic energy of Sample B's atoms.

Answer:

       This pH is 7.

Explanation:

Strong acids and strong bases ionize completely in aqueous solutions. The ionization of strong acids produce hydronium ions, H₃O⁺, and the ionization of strong bases produce hydroxide ions, OH⁻.

Since the ionization of strong acids and bases progress until completion, there is not reverse reaction.

The definition of pH is pH = - log [H₃O⁺]. Acids have low pH (below 7, and greater than 0) and bases have high pH (above 7 and less than 14). Neutral solutions have pH = 7.

Acid-base titrations are a method to determine the concentration of an acid from the known concentration of a base, or the concentraion of a base from the known concentration of an acid.

The equivalence point of the titration is the point at which the the number of moles of hydronium ions and hydroxide ions are equal.

Then, at that point, the hydronium and hydroxide ions will be in the stoichiometric proportion to form a neutral solution, i.e. the pH of the solution wiill be 7.

Not all titrations of a strong base with a strong acid have the same pH at the equivalence point. The pH value will be different when a weak acid is titrated with a strong base due to the presence of the weak conjugate base in the reaction mixture.

No, not all titrations of a strong base with a strong acid have the same pH at the equivalence point. For instance, the titration of 25.00 mL of 0.100 M HCl (a strong acid) with 0.100 M NaOH (a strong base) has a pH of 7.00 at the equivalence point. However, when a weak acid, such as acetic acid, is titrated with a strong base like NaOH, the pH at the equivalence point is 8.72, because the reaction mixture contains a weak conjugate base (acetate ion). The pH value at the equivalence point is dependent on whether the acid is strong or weak, and the presence of its conjugate base.

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Answer:

Explanation:

In a chemical reaction, as a result of the law of conservation of mass, reactants combine in fixed proportions to form the products.

Then, a chemical reaction is characterized by cuantitative relations between the atoms and compounds, which permit to make predictions on how much product can be obtained from certain amounts of reactants or how much of each reactant you would need to obtain a desired amount of product.

Stoichiometry is the use of the mole coefficients of a chemical equation to state ratios and set proportions, and, so, determine the number of moles or masses of reactants and products.

The calculation of quantities in chemical reactions is referred to as stoichiometry. It's about using a balanced chemical equation to figure out the quantitative relationships between the amounts of reactants and products. This process can be used in situations like quantitative chemical analysis.

The calculation of quantities in chemical reactions is referred to as stoichiometry. This means using a balanced chemical equation to determine the quantitative relationships between the quantities of reactants and products. In this process, chemical species' coefficients, derived from the balanced chemical equation, are used to provide the relative numbers, allowing a quantitative assessment of the relationships between the substances consumed and produced by the reaction.

Applying stoichiometry becomes particularly essential when dealing with more realistic situations, such as when reactants are not present in stoichiometric amounts. For instance, it is used in quantitative chemical analysis, such as titrations, where the volume of a titrant solution required to fully react with a sample solution is measured. This volume is subsequently used to calculate the concentration of analyte in the sample.

In other words, stoichiometry is the cornerstone of chemical calculations, providing a method to predict yields, determine reaction efficiencies, and understand the fundamental aspects of the reaction's reaction's stoichiometry. Quite simply, stoichiometry is a powerful tool that provides important insights into the world of chemistry.

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Answer:

0.744 mol

Explanation:

the balanced equation for the reaction is

8Fe + S₈ ---> 8FeS

molar ratio of Fe to S₈ is 8:1

number of moles of Fe - 55.0 g / 56 g/mol = 0.98 mol

number of moles of S - 23.8 g / 256 g/mol = 0.093 mol

if we are to assume that S₈ is the limiting reactant

if 1 mol of S₈ reacts with 8 mol of Fe

then 0.093 mol of S₈ reacts with - 8 x 0.093 mol = 0.744 mol of Fe

however there's 0.98 mol of Fe present but only 0.744 mol of Fe is needed

therefore Fe is in excess and S₈ is the limiting reagent

molar ratio of S₈ to FeS is 1:8

then 0.093 mol of S₈ reacts with - 8 x 0.093 = 0.744 mol of FeS

number of FeS moles produced is 0.744 mol

Answer:

0.74 moles iron (III) sulfide

Explanation:

From the balanced equation of reaction:

    [tex]Fe + S --> FeS[/tex]

1 mole of Fe reacts with 1 mole of S to give 1 mole of FeS.

moles = [tex]\frac{mass}{molar mass}[/tex]

mole of Fe = 55/55.8 = 0.99 moles

mole of S = 23.8/32.07 = 0.74 moles

Sulfur is limited in quantity and will therefore determine the rate of reaction.

1 mole of sulfur gives 1 mole of FeS

0.74 moles of sulfur will therefore give 0.74 moles of FeS.

0.74 moles iron (III) sulfide will be produced.

Answer:

a. +6;

b. +5;

c. +3.

Explanation:

Start with elements with well-known oxidation states.

The oxidation state on oxygen O in compounds is mostly -2. Common exceptions include:

The oxidation state on group 1 metals (Li, Na, K, etc.) in compounds is mostly +1.

The oxidation state on group 2 metals (Be, Mg, Ca, etc.) in compounds is mostly +2.

Barium Ba is a group 2 metal. The oxidation state on Ba in the compound BaSO₄ is expected to be +2.

The oxidation state on hydrogen H in compounds is mostly +1. The oxidation state on H might be negative when it is bonded to metals.  

The oxidation state on halogens (F, Cl, Br, etc.) is mostly -1. The oxidation state may vary when the halogen is bonded to oxygen or another halogen element.

Compounds are neutral. The oxidation state on all atoms in a compound shall add up to 0. Both BaSO₄ and HClO₂ are neutral.

Oxidation states:

Let the oxidation state on S be x.

2 + x + 4 × (-2) = 0;

x = 6.

Hence, the oxidation state on S in BaSO₄ is +6.

Oxidation states:

Let the oxidation state on Cl be x.

Refer to the equation in BaSO₄ as an example. Try setting up the equation on your own.

x = 3.

Hence, the oxidation state on Cl is +3.

Ions carry charge. Oxidation states on atoms in an ion shall add up to the charge of the ion. The superscript of an ion shows its charge. The superscript 3- in the phosphate ion shows that the ion carries a charge of -3.

Oxidation states:

Let the oxidation state on P be x.

x + 4 × (-2) = -3;

x = 5.

Hence, the oxidation state on P is +5.

Answer:0.75 atm

Explanation: 0.75 atm is the pressure if the gas

Answer:

a. 0.31 g

Explanation:

So, 70 days represent (70 days/ 14 days = 5.0 half-lives).

10 g → (first half-life = 14 days) 5 g → (second half-life = 28 days) 1.5 g → (third half-life = 42 days) 1.25 g → (fourth half-life = 56 days) 0.625 g → (fifth half-life = 70 days) 0.3125 g.

So, the right choice is: a. 0.31 g.

Answer:

0.31 g

Explanation:

proved the answer right below

Do you mean people become part of a 'circut' when a person becomes part of an electrical current?

Answer:

Circuit

Explanation:

People become part of the circuit

Answer:

It's a.

Explanation:

The reaction will proceed at an increasing rate.

The effect that does super critical mass have on a nuclear reaction, the reaction to have on a nuclear reaction, the reaction rate increases. The correct option is a.

Nuclear reaction is the reaction in which two nuclei are combined to form nuclides or one nuclei combine with a subatomic particle to form nuclides.

There are four types of nuclear reaction, fission, fusion, decay and transmutation.

Thus, the correct option is a, the reaction rate increases.

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Answer: 1.07 V

Explanation: [tex]E^0_{[Zn^{2+}/Zn}=-0.76V[/tex]

[tex]E^0_{[Cu^{2+}/Cu]}=+0.34V[/tex]

The metal with negative reduction potential will easily lose electrons and thus is oxidized and the one with positive reduction potential will easily gain electrons and thus is reduced.

[tex]Zn+Cu^{2+}\rightarrow Zn^{2+}+Cu[/tex]

[tex]E^o_{cell}[/tex] = standard electrode potential =[tex]E^0_{cathode}- E^0_{anode}=0.34-(-0.76)=1.1V[/tex]

Using Nernst equation:

[tex]E_{cell}=E^o_{cell}-\frac{0.0592}{n}\log \frac{[Zn^{2+}]}{[Cu^{2+}]}[/tex]

where,

n = number of electrons in oxidation-reduction reaction = 2

[tex]E_{cell}=1.10-\frac{0.0592}{2}\log \frac{[0.1]}{[0.01]}[/tex]

[tex]E_{cell}=1.07V[/tex]

Answer:

H2O2 - - - - - -> H2O + O2

+1 +2 0

Oxidation O. S.

state of of Oxygen

Oxygen

[tex]2H_{2}O_{2}[/tex]--------->  [tex]2H_{2}O+O_{2}[/tex] is the equation given for the oxidation of peroxide during a redox reaction.

The reaction in which both oxidation and reduction can simultaneously occur to give raise to product is called as redox reaction.

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A. Polyatomic Ion

Why? Nitrogen and Hydrogen are covalently bonded, and there are 4 Nitrogen atoms (fitting the prefix “poly”, meaning “many”).

[tex]NH^{+ 4}[/tex] is a A. Polyatomic ion

When two atoms combine with each other through a covalent bond it leads to the formation of charged species called as polyatomic ions.  

The ammonium cation is a decidedly accused polyatomic particle of the synthetic recipe [tex]NH^{+ 4}[/tex]. It is shaped by the protonation of ammonia.  Ammonium is additionally a general name for decidedly charged or protonated substituted amines and quaternary ammonium cations [tex](NH^{+ 4})[/tex], where at least one hydrogen molecules are supplanted by natural gatherings.

Final answer:

To find the number of grams in 3 moles of A2, we can use the formula: grams = moles * molar mass. In this case, the number of grams would be 6X grams.

Explanation:

To determine the number of grams in 3 moles of A2, we need to know the molar mass of A2. Assuming A is a diatomic gas, its molar mass would be the sum of the atomic masses of the two atoms in its formula. Let's say the atomic mass of A is X and the atomic mass of B is Y. Since A2 has two atoms of A, the molar mass of A2 would be 2X. Therefore, to find the number of grams in 3 moles of A2, we can use the formula: grams = moles * molar mass. In this case, the number of grams would be 3 * 2X = 6X grams. Hence, the correct option is c.) 6.

The correct answer is c.) 6. in 3 moles of A2 (with an assumed atomic mass of 3 units for element A), there are 18 grams.

To determine the number of grams in 3 moles of A2, we first need to find the molar mass of A2. The molar mass of a substance is the mass in grams of one mole of that substance. Since A2 represents a diatomic molecule (two atoms of A), we'll calculate the molar mass by adding the atomic masses of two atoms of element A.

Looking at the periodic table, suppose the atomic mass of element A is X units. As A2 consists of two atoms of A, the molar mass of A2 is 2 * X units.

Without specific atomic masses provided, let's assume a hypothetical atomic mass of 3 units for element A. Therefore, the molar mass of A2 would be 2 * 3 = 6 units.

Now, to find the grams in 3 moles of A2, we use the formula:

[tex]\[ \text{Grams} = \text{Number of Moles} \times \text{Molar Mass} \][/tex]

Plugging in the values, we get:

[tex]\[ \text{Grams} = 3 \, \text{moles} \times 6 \, \text{units/mol} = 18 \, \text{units} \][/tex]

Thus, in 3 moles of A2 (with an assumed atomic mass of 3 units for element A), there are 18 grams.

This calculation relies on the assumed atomic mass for element A. However, the specific atomic masses for the elements A and B in the diatomic gases are essential for accurate calculations. The given question lacks this information, so the assumption of the atomic mass was necessary for computation.

4.5 x 10^25 molecules of SO2

Answer:

No, it is not balanced.

The balanced equation is: Zn(OH)₂ + 2NaOH → Na₂ZnO₂ + 2H₂O.

Explanation:

The no. of Na atoms in reactants side is 1 but in products side is 2.

The no. of H atoms in reactants side is 3 but in product side is 2.

So, the equation is not balanced.

Zn(OH)₂ + 2NaOH → Na₂ZnO₂ + 2H₂O.

Zn (1), O (4), H (4), and Na (2).

Answer:

= 6.0 moles

Explanation:

The equation for the reaction is;

2 CH3OH + 3 O2 → 2 CO2 + 4 H2O

We are given 4.0 moles of CH3OH.

From the reaction; 2 moles of CH3OH requires 3 moles of O2,

Therefore; moles of Oxygen will be;

= 4.0 moles × 3/2

= 6.0 moles

Therefore; 6.0 moles of Oxygen gas are required to react completely with 4.0 moles CH3OH.

Hi there nice to meet u thank you

To find how much calcium is contained in 40.0 g of calcium fluoride, calculate the moles of calcium fluoride and then determine the moles of calcium using its mass. 40.0 g of calcium fluoride contains 0.192 mol of calcium.

To calculate the amount of calcium in 40.0 g of calcium fluoride, we need to first determine the molar mass of calcium fluoride (CaF2), which is 78.08 g/mol. Next, we can calculate the moles of calcium fluoride in 40.0 g using the formula:

Moles = Mass / Molar mass = 40.0 g / 78.08 g/mol = 0.512 mol

Since the calcium fluoride contains 7.70 g of calcium, we can determine the moles of calcium using its molar mass (40.08 g/mol):

Moles of calcium = Mass of calcium / Molar mass of calcium = 7.70 g / 40.08 g/mol = 0.192 mol

Therefore, 40.0 g of calcium fluoride contains 0.192 mol of calcium.

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