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

$$\displaystyle \%\ \mathrm{yield} = \frac{\text{actual yield}}{\text{theoretical yield}} \times 100$$

Question 1

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

Accepted Answer

It is the reactant that determines the amount of product formed.

Question 2

A student is asked to prepare 500.0 mL of 1.00 M $$(\mathrm{NH}_4)_3\mathrm{PO}_4$$ solution. What mass of $$(\mathrm{NH}_4)_3\mathrm{PO}_4 is $$required? (Molar mass = 149.09 g/mol)

Accepted Answer

$$74.5\ \mathrm{g}$$

Question 3

Which of the following is the correct balanced equation for the reaction between silver nitrate and potassium iodide in aqueous solution?

Accepted Answer

$$\mathrm{AgNO}_3 (aq) + \mathrm{KI} (aq) \rightarrow \mathrm{AgI} (s) + \mathrm{KNO}_3 (aq)$$

Question 4

A 1.154 g sample of sulfur reacts with fluorine to form a compound with the formula $$SF_x. If 5.722 g of$$ $$F_2 is $$used, what is the value of $$x$$?

Accepted Answer

$$6$$

Question 5

Which of the following statements about strong and weak electrolytes is correct?

Accepted Answer

Strong electrolytes dissociate completely in water, while weak electrolytes dissociate only partially.

Question 6

Given the reaction: $$2\mathrm{NaOH} (aq) + \mathrm{Pb(NO}_3)_2 (aq) \rightarrow 2\mathrm{NaNO}_3 (aq) + \mathrm{Pb(OH)}_2 (s)$$, if 0.200 mol $$\mathrm{NaOH} is $$mixed with 0.100 mol $$\mathrm{Pb(NO}_3)_2$$, how many moles of $$\mathrm{Pb(OH)}_2$$ will precipitate?

Accepted Answer

$$0.100\ \mathrm{mol}$$

Question 7

Which of the following is the correct net ionic equation for the reaction between $$\mathrm{Na}_2\mathrm{SO}_4$$ and $$\mathrm{BaCl}_2 in $$aqueous solution?

Accepted Answer

$$\mathrm{Ba}^{2+} (aq) + \mathrm{SO}_4$$^{2-}$$ (aq) \rightarrow \mathrm{BaSO}_4 (s)$$

Question 8

A solution is prepared by dissolving 10.0 g of $$\mathrm{NaCl} in $$enough water to make 500.0 mL of solution. What is the molarity of the solution? (Molar mass of $$\mathrm{NaCl} = 58.44 g/$$mol)

Accepted Answer

$$0.342\ \mathrm{M}$$

Question 9

Which of the following is the correct sequence of steps for balancing a redox reaction in acidic solution?

Accepted Answer

Assign oxidation states, separate into half-reactions, balance all elements except H and O, balance O with $$\mathrm{H}_2\mathrm{O}$$, balance H with $$\mathrm{H}^+$$, balance charge with electrons, combine and simplify.

Question 10

A combustion analysis of a hydrocarbon yields 2.20 g of $$\mathrm{CO}_2$$ and 0.90 g of $$\mathrm{H}_2\mathrm{O}. $$What is the empirical formula of the hydrocarbon?

Accepted Answer

$$\mathrm{CH}_2$$

Question 11

Which of the following solutions has the highest total ion concentration?

Accepted Answer

$$0.10\ \mathrm{M}\ \mathrm{BaCl}_2$$

Question 12

Which of the following acids is a strong acid?

Accepted Answer

$$\mathrm{HNO}_3$$

Question 13

What is the percent yield if 27.0 g of $$\mathrm{PCl}_3 is $$produced from a reaction with a theoretical yield of 30.0 g?

Accepted Answer

$$90\%$$

Question 14

Which of the following best describes a spectator ion?

Accepted Answer

An ion that does not participate in the chemical reaction and remains unchanged in solution.

Question 15

If 100.0 mL of 12 M HCl is diluted to a final volume of 1.00 L, what is the final concentration?

Accepted Answer

$$1.2\ \mathrm{M}$$

Question 16

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

Accepted Answer

$$\displaystyle \%\ \mathrm{yield} = \frac{	ext{actual yield}}{	ext{theoretical yield}} 	imes 100$$

Question 17

Which of the following is a correct net ionic equation for the reaction of hydrochloric acid with sodium hydroxide?

Accepted Answer

$$\mathrm{H}^+ (aq) + \mathrm{OH}^- (aq) \rightarrow \mathrm{H}_2\mathrm{O} (l)$$

Question 18

A solution contains $$0.10\ \mathrm{M}\ \mathrm{K}_3\mathrm{PO}_4. $$What is the total ion concentration in the solution?

Accepted Answer

$$0.40\ \mathrm{M}$$

Question 19

Which of the following is the correct order of steps for preparing a standard solution in a volumetric flask?

Accepted Answer

Dissolve solute in less than the final volume, swirl to mix, add water to the calibration line, stopper and invert to mix.

Balancing Equations and Reaction Stoichiometry: Study Notes

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