Q: Which of the following is the correct formula for calculating parts per billion (ppb)?

$$(\text{mass of solute} / \text{mass of solution}) \times 10^9$

Q: Which of the following is the correct formula for mass-volume percentage?

$$(\text{mass of solute} / \text{volume of solution}) \times 100$$

Question 1

Which of the following best describes the concept of a limiting reactant in a chemical reaction?

Accepted Answer

The reactant that determines the maximum amount of product that can be formed.

Question 2

Given the balanced equation: $$2KClO_3 \rightarrow 2KCl + 3O_2$$, how many moles of $$O_2$$ are produced from 4 moles of $$KClO_3$$?

Accepted Answer

$$6$$ moles

Question 3

A student wants to dilute $$52.10 mL of$$ $$0.178 M $$HCl to make a $$0.132 M $$solution. What will be the final volume after dilution?

Accepted Answer

$$70.26 mL$$

Question 4

If $$200.0 g of a $$solution contains $$390 mg of $$sodium ion, what is the concentration in ppm?

Accepted Answer

$$1.95 	imes 10^3$ ppm

Question 5

In the reaction $$Fe_2O_3 + 3CO \rightarrow 2Fe + 3CO_2$$, if $$85.8 g of$$ $$Fe_2O_3$$ and $$72.3 g of$$ $$CO$$ are used, which is the limiting reactant?

Accepted Answer

$$CO$$

Question 6

What is the percent yield if the theoretical yield of Fe is $$114.0 g $$and the actual yield is $$85.8 g$$?

Accepted Answer

$$75.3\%$$

Question 7

Which equation is used to calculate the volume required to dilute a solution?

Accepted Answer

$$M_1V_1 = M_2V_2$$

Question 8

A solution is prepared by dissolving $$10.0 g of $$NaCl in $$100.0 g of $$water. What is the mass percentage of NaCl in the solution?

Accepted Answer

$$9.09\%$$

Question 9

In the reaction $$N_2 + 3H_2$$ \rightarrow 2NH_3$$, how many grams of NH_3$ can be synthesized from 5.22$ kg of N_2$ and 31.5$ kg of H_2$?

Accepted Answer

$$6.34 	imes 10^3$ g

Question 10

Which of the following is the correct formula for calculating parts per billion (ppb)?

Accepted Answer

$$(	ext{mass of solute} / 	ext{mass of solution}) 	imes 10^9$

Question 11

If $$0.859$$ mol of $$CO_2 is $$produced in photosynthesis, how many grams of $$CO_2 is $$this?

Accepted Answer

$$37.8 g$$

Question 12

A solution contains $$25 mL of $$ethanol in $$100 mL of $$solution. What is the volume percentage of ethanol?

Accepted Answer

$$25\%$$

Question 13

Which of the following statements about stoichiometry is correct?

Accepted Answer

Stoichiometry requires converting all quantities to moles before calculations.

Question 14

In the reaction $$C_6H_{12}O_6$ + 6O_2 \rightarrow 6CO_2 + 6H_2O$$, how many moles of $$CO_2$$ are produced from $$0.4135$$ mol of $$C_6H_{12}O_6$?

Accepted Answer

$$2.48$$ mol

Question 15

A reaction has a theoretical yield of $$50 g $$and an actual yield of $$40 g. $$What is the percent yield?

Accepted Answer

$$80\%$$

Question 16

Which of the following is NOT a reason why the actual yield of a reaction is less than the theoretical yield?

Accepted Answer

All reactions always proceed with 100% efficiency.

Question 17

If $$3$$ moles of $$NH_3$$ are produced from $$2$$ moles of $$N_2$$ and $$6$$ moles of $$H_2$$, what is the limiting reactant?

Accepted Answer

$$H_2$$

Question 18

Which of the following is the correct formula for mass-volume percentage?

Accepted Answer

$$(	ext{mass of solute} / 	ext{volume of solution}) 	imes 100$$

Question 19

A chemical reaction produces $$8.0$$ moles of $$CO_2$$ from $$16$$ moles of $$C_6H_{12}O_6$. What is the mole ratio of CO_2$ to C_6H$$_{12}$$O_6$$?

Accepted Answer

$$0.5$$

Stoichiometry, Limiting Reactants, Solution Concentrations, and Yield Calculations

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