Q: How many molecules are present in $$3.00$$ mol of $$N_2$$?

$$1.81 \times 10$$^{24}$$ molecules

Q: Which of the following is the correct formula for calculating percent yield?

$$\text{Percent Yield} = \dfrac{\text{Actual Yield}}{\text{Theoretical Yield}} \times 100$$

Q: How many atoms are present in $$3.91$$ mol of xenon ($$Xe$$)? (Avogadro's number $$= 6.022 \times 10$$^{23}$$)

$$2.35 \times 10$$^{24}$$ atoms

Q: If $$1.00 g of$$ $$C_6H_{12}O_6$ (molar mass 180.0$ g/mol) is completely combusted, how many moles of CO_2$ are produced? (Reaction: C_6H$$_{12}$$O_6 + 6O_2$$ \rightarrow 6CO_2 + 6H_2O$$)

$$0.0333$$ mol \times 6 = 0.200$ mol

Question 1

Which statement best describes the Law of Conservation of Mass as it applies to chemical reactions?

Accepted Answer

The total mass of reactants equals the total mass of products in a chemical reaction.

Question 2

What is the correct balanced chemical equation for the combustion of methane ($$CH_4) in $$oxygen?

Accepted Answer

$$CH_4 + 2O_2$$ \rightarrow $$CO_2 + 2H_2O$

Question 3

Which of the following is the empirical formula for glucose ($$C_6H_{12}O_6$)?

Accepted Answer

$$CH_2O$$

Question 4

A sample contains 123.2 g of $$Cl_2. $$How many moles of $$Cl_2$$ are present? (Molar mass of $$Cl_2 = 70.90$ g/mol)

Accepted Answer

$$1.74$$ mol

Question 5

Which of the following best describes a decomposition reaction?

Accepted Answer

A single compound breaks down into two or more simpler substances.

Question 6

Calculate the percent composition of carbon in ethane ($$C_2H_6$$), given its formula weight is $$30.0$$ amu.

Accepted Answer

$$80.0\%$$

Question 7

How many molecules are present in $$3.00$$ mol of $$N_2$$?

Accepted Answer

$$1.81 	imes 10$$^{24}$$ molecules

Question 8

Which of the following is the correct formula for calculating percent yield?

Accepted Answer

$$	ext{Percent Yield} = \dfrac{	ext{Actual Yield}}{	ext{Theoretical Yield}} 	imes 100$$

Question 9

If $$2.00 g of$$ $$A ($$molar mass $$20 g/$$mol) and $$3.00 g of$$ $$B ($$molar mass $$30 g/$$mol) react according to $$A + 2B \rightarrow AB_2$, what is the limiting reactant?

Accepted Answer

$$B$$

Question 10

A compound contains $$61.31\% C$$, $$5.14\% H$$, $$10.21\% N$$, and $$23.33\% O by $$mass. What is the empirical formula of the compound?

Accepted Answer

$$C_7H_7NO_2$$

Question 11

What is the molecular weight of calcium chloride ($$CaCl_2$$)? (Atomic weights: Ca = $$40.1$$ amu, Cl = $$35.5$$ amu)

Accepted Answer

$$111.1$$ amu

Question 12

Which of the following is NOT a type of chemical reaction discussed in the study materials?

Accepted Answer

Electrolysis reaction

Question 13

How many atoms are present in $$3.91$$ mol of xenon ($$Xe$$)? (Avogadro's number $$= 6.022 	imes 10$$^{23}$$)

Accepted Answer

$$2.35 	imes 10$$^{24}$$ atoms

Question 14

Which of the following statements about coefficients and subscripts in chemical equations is correct?

Accepted Answer

Coefficients indicate the number of molecules or moles; subscripts indicate the number of atoms in each molecule.

Question 15

A reaction produces $$4.0 g of $$product, but the theoretical yield is $$5.0 g. $$What is the percent yield?

Accepted Answer

$$80\%$$

Question 16

Which of the following is the correct sequence of steps to balance a chemical equation?

Accepted Answer

Balance metals first, then nonmetals, then hydrogen and oxygen.

Question 17

If $$1.00 g of$$ $$C_6H_{12}O_6$ (molar mass 180.0$ g/mol) is completely combusted, how many moles of CO_2$ are produced? (Reaction: C_6H$$_{12}$$O_6 + 6O_2$$ \rightarrow 6CO_2 + 6H_2O$$)

Accepted Answer

$$0.0333$$ mol 	imes 6 = 0.200$ mol

Question 18

Which of the following is true about Avogadro's number?

Accepted Answer

It is the number of atoms, ions, or molecules in one mole of a substance.

Question 19

A student mixes $$2.0 g of$$ $$A ($$molar mass $$20 g/$$mol) and $$3.0 g of$$ $$B ($$molar mass $$30 g/$$mol) to produce $$AB_2 ($$molar mass $$80 g/$$mol) via $$A + 2B \rightarrow AB_2$. What is the maximum mass of AB_2$ that can be formed?

Accepted Answer

$$4.0 g$$

Chapter 3: Chemical Reactions and Reaction Stoichiometry – Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards