Q: Which equation correctly represents the calculation of molarity ($$M) $$for a solution?

$$M = \dfrac{\text{moles of solute}}{\text{volume of solution in liters}}$$

Q: Which of the following is the correct formula for calculating the percent composition of an element in a compound?

$$\%\text{ composition} = \dfrac{\text{mass of element in 1 mole of compound}}{\text{molar mass of compound}} \times 100$$

Question 1

Which of the following best describes the Law of Conservation of Mass as it applies to a chemical reaction in a closed system?

Accepted Answer

The total mass of reactants equals the total mass of products.

Question 2

A student mixes 10.0 g of sodium chloride ($$\mathrm{NaCl}) $$with 20.0 g of silver nitrate ($$\mathrm{$$AgNO_3$$}) in $$water, producing a precipitate of silver chloride ($$\mathrm{AgCl}) $$and sodium nitrate ($$\mathrm{$$NaNO_3$$}). If $$the total mass of the products is measured to be 30.0 g, what does this result demonstrate?

Accepted Answer

The Law of Conservation of Mass is confirmed.

Question 3

Which equation correctly represents the calculation of molarity ($$M) $$for a solution?

Accepted Answer

$$M = \dfrac{	ext{moles of solute}}{	ext{volume of solution in liters}}$$

Question 4

A chemist needs to prepare 250 mL of a 0.50 M $$\mathrm{NaOH}$$ solution. How many grams of $$\mathrm{NaOH} ($$molar mass = 40.0 g/mol) are required?

Accepted Answer

5.0 g

Question 5

Which of the following is the correct balanced chemical equation for the reaction between hydrochloric acid ($$\mathrm{HCl}) $$and sodium hydroxide ($$\mathrm{NaOH}$$)?

Accepted Answer

$$\mathrm{HCl} + \mathrm{NaOH} \rightarrow \mathrm{NaCl} + \mathrm{H_2O}$$

Question 6

Which statement best explains why water ($$\mathrm{H_2O}) is $$considered a polar molecule?

Accepted Answer

Water has an uneven distribution of electron density due to its bent shape and difference in electronegativity between H and O.

Question 7

A sample of gas occupies 2.0 L at 1.0 atm and 300 K. If the pressure is increased to 2.0 atm at constant temperature, what will be the new volume of the gas? (Assume ideal gas behavior.)

Accepted Answer

1.0 L

Question 8

Which of the following is the correct formula for calculating the percent composition of an element in a compound?

Accepted Answer

$$\%	ext{ composition} = \dfrac{	ext{mass of element in 1 mole of compound}}{	ext{molar mass of compound}} 	imes 100$$

Question 9

Which statement about oxidation numbers is correct?

Accepted Answer

The oxidation number of oxygen in most compounds is $$-2.$$

Question 10

A student is asked to write the empirical formula for glucose ($$\mathrm{C_6H_{12}O_6$}). $$What is the correct empirical formula?

Accepted Answer

$$\mathrm{CH_2O}$$

Question 11

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

Accepted Answer

The reactant that determines the amount of product formed.

Question 12

A reaction requires 2.0 mol of $$\mathrm{H_2$}$$ and 1.0 mol of $$\mathrm{O_2$} to $$produce water. If you have 3.0 mol of $$\mathrm{H_2$}$$ and 2.0 mol of $$\mathrm{O_2$}$$, which is the limiting reactant?

Accepted Answer

$$\mathrm{O_2$}$$

Question 13

Which of the following is a correct statement about intermolecular forces?

Accepted Answer

Hydrogen bonding is stronger than London dispersion forces.

Question 14

Which of the following best explains why ionic compounds tend to have high melting points?

Accepted Answer

Ionic compounds have strong electrostatic attractions between oppositely charged ions.

Question 15

A solution is prepared by dissolving 5.0 g of $$\mathrm{KCl} ($$molar mass = 74.6 g/mol) in enough water to make 500 mL of solution. What is the molarity of the solution?

Accepted Answer

0.134 M

Question 16

Which of the following is the correct net ionic equation for the reaction between aqueous solutions of $$\mathrm{$$AgNO_3$$}$$ and $$\mathrm{NaCl}$$?

Accepted Answer

$$\mathrm{Ag^+ (aq) + Cl^- (aq) \rightarrow AgCl (s)}$$

Question 17

Which of the following is a correct statement about the use of significant figures in calculations?

Accepted Answer

The result of a multiplication or division should have the same number of significant figures as the measurement with the fewest significant figures.

Question 18

Which of the following best describes the difference between a physical change and a chemical change?

Accepted Answer

A chemical change results in the formation of new substances, while a physical change does not.

General Chemistry I (CHEM 1113) Syllabus and Study Guide

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