Question 1

A sample of glucose ($$\mathrm{C_6H_{12}O_6$}) $$has a mass of 18.0 g. What is the number of moles of glucose in the sample? (Molar mass of $$\mathrm{C_6H_{12}O_6$} is 180 g/$$mol.)

Accepted Answer

$$0.10$$ mol

Question 2

Which of the following best describes a saturated solution?

Accepted Answer

A solution in which the maximum amount of solute has dissolved at a given temperature.

Question 3

What is the percent composition by mass of oxygen in water ($$\mathrm{H_2O}$$)? (Atomic masses: H = 1.0, O = 16.0)

Accepted Answer

$$88.9\%$$

Question 4

A compound contains $$40.0\%$$ carbon, $$6.7\%$$ hydrogen, and $$53.3\%$$ oxygen by mass. What is its empirical formula? (Atomic masses: C = 12.0, H = 1.0, O = 16.0)

Accepted Answer

$$\mathrm{CH_2O}$$

Question 5

If the empirical formula of a compound is $$\mathrm{CH_2$}$$ and its molar mass is $$56\ \mathrm{g/mol}$$, what is its molecular formula? (Empirical formula mass = $$14\ \mathrm{g/mol})$$

Accepted Answer

$$\mathrm{C_4H_8}$$

Question 6

Which of the following statements is true regarding electrolytes?

Accepted Answer

Ionic compounds are strong electrolytes because they dissociate completely in water.

Question 7

How many grams of sodium chloride ($$\mathrm{NaCl}$$, molar mass $$58.5\ \mathrm{g/mol}) $$are required to prepare $$250\ \mathrm{mL} of a$$ $$0.200\ \mathrm{M}$$ solution?

Accepted Answer

$$2.93\ \mathrm{g}$$

Question 8

Which of the following best defines molarity ($$M$$)?

Accepted Answer

Moles of solute per liter of solution

Question 9

Which of the following substances will NOT dissociate into ions when dissolved in water?

Accepted Answer

Sugar ($$\mathrm{C$$_{12}$$H_{22}O$$_{11}}$)

Question 10

A solution is prepared by dissolving $$5.00\ \mathrm{g} of$$ $$\mathrm{KBr} ($$molar mass $$119.0\ \mathrm{g/mol}) in $$enough water to make $$250.0\ \mathrm{mL} of $$solution. What is the molarity of the solution?

Accepted Answer

$$0.168\ \mathrm{M}$$

Question 11

Which of the following is the correct sequence for converting grams of a compound to moles of a specific element in that compound?

Accepted Answer

Grams of compound $$\rightarrow$$ Moles of compound $$\rightarrow$$ Moles of element

Question 12

A $$1.0\ \mathrm{L}$$ solution contains $$0.5\ \mathrm{mol} of$$ $$\mathrm{Na_2SO_4}. $$What is the concentration of sodium ions in the solution?

Accepted Answer

$$1.0\ \mathrm{M}$$

Question 13

Which of the following best describes a solute?

Accepted Answer

The substance that is dissolved in a solution

Question 14

A chemist needs to prepare $$500\ \mathrm{mL} of a$$ $$1.00\ \mathrm{M}$$ solution of $$\mathrm{H_2SO_4} ($$molar mass $$98.0\ \mathrm{g/mol}). $$How many grams of $$\mathrm{H_2SO_4}$$ are required?

Accepted Answer

$$49.0\ \mathrm{g}$$

Question 15

Which of the following is a nonelectrolyte when dissolved in water?

Accepted Answer

Ethanol ($$\mathrm{C_2H_5OH})$$

Question 16

A $$250\ \mathrm{mL}$$ solution contains $$0.10\ \mathrm{mol} of$$ $$\mathrm{NaOH}. $$What is the molarity of the solution?

Accepted Answer

$$0.40\ \mathrm{M}$$

Question 17

Which of the following statements about molecular and ionic substances in water is correct?

Accepted Answer

Ionic substances dissociate into ions, while most molecular substances do not.

Question 18

A solution is made by dissolving $$10.0\ \mathrm{g} of$$ $$\mathrm{NaOH} ($$molar mass $$40.0\ \mathrm{g/mol}) in $$enough water to make $$500\ \mathrm{mL} of $$solution. What is the molarity of the solution?

Accepted Answer

$$0.50\ \mathrm{M}$$

Question 19

Which of the following is the correct definition of concentration?

Accepted Answer

The amount of solute present in a given quantity of solvent or solution

Compounds, Solutions, and Their Composition

Guida di studio - Domande di pratica

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