Q: Which of the following reactions is an example of an oxidation-reduction (redox) reaction?

$$2\text{Na} + \text{Cl}_2 \rightarrow 2\text{NaCl}$$

Q: A gas occupies a volume of $$2.0 L at a $$pressure of $$1.0$$ atm and a temperature of $$300 K. $$Using the ideal gas law $$PV = nRT$$, what is the number of moles of gas present? (Use $$R = 0.0821 L$$·atm·mol$$^{-1}$$·K$$^{-1})$$

$$n = \frac{(1.0)(2.0)}{0.0821 \times 300} = 0.081$$ moles

Q: Which of the following is the correct balanced equation for the combustion of methane ($$\text{CH}_4$$)?

$$\text{CH}_4 + 2\text{O}_2 \rightarrow \text{CO}_2 + 2\text{H}_2\text{O}$$

Question 1

Which of the following best describes the process of converting 0.00567 kilograms to milligrams using dimensional analysis?

Accepted Answer

Multiply by $$10^6 to $$convert kilograms to milligrams: $$0.00567 	imes 10^6$ = 5670 mg.$$

Question 2

A sample contains $$3.01 	imes 10$$^{23}$$ molecules of water. How many moles of water does this represent?

Accepted Answer

$$0.5$$ moles

Question 3

Which of the following is the correct scientific notation for the number 0.000345?

Accepted Answer

$$3.45 	imes 10$$^{-4}$$

Question 4

A balanced chemical equation is required for which of the following calculations?

Accepted Answer

Stoichiometric calculations to determine the amount of product formed from a given amount of reactant.

Question 5

Which of the following reactions is an example of an oxidation-reduction (redox) reaction?

Accepted Answer

$$2	ext{Na} + 	ext{Cl}_2 ightarrow 2	ext{NaCl}$$

Question 6

According to the first law of thermodynamics, which of the following statements is true?

Accepted Answer

Energy cannot be created or destroyed, only transformed from one form to another.

Question 7

A chemical reaction absorbs heat from its surroundings. Which term best describes this process?

Accepted Answer

Endothermic

Question 8

A gas occupies a volume of $$2.0 L at a $$pressure of $$1.0$$ atm and a temperature of $$300 K. $$Using the ideal gas law $$PV = nRT$$, what is the number of moles of gas present? (Use $$R = 0.0821 L$$·atm·mol$$^{-1}$$·K$$^{-1})$$

Accepted Answer

$$n = \frac{(1.0)(2.0)}{0.0821 	imes 300} = 0.081$$ moles

Question 9

Which of the following statements about the properties of gases is correct?

Accepted Answer

The pressure of a gas increases as its volume decreases, if temperature and amount of gas are constant.

Question 10

An atom of sodium ($$^{23}_{11}	ext{Na}) $$has how many protons, neutrons, and electrons?

Accepted Answer

11 protons, 12 neutrons, 11 electrons

Question 11

Which of the following best explains why elements in the same group of the Periodic Table have similar chemical properties?

Accepted Answer

They have the same number of valence electrons.

Question 12

Which of the following is a metalloid?

Accepted Answer

Silicon (Si)

Question 13

A patient receives an intravenous solution containing $$0.9$$ grams of NaCl per $$100 mL. $$How many moles of NaCl are in $$250 mL of $$this solution? (Molar mass of NaCl = $$58.44 g/$$mol)

Accepted Answer

$$0.0385$$ moles

Question 14

Which of the following best describes the relationship between atomic structure and chemical behavior?

Accepted Answer

The number and arrangement of electrons determine how an atom interacts with other atoms.

Question 15

A reaction releases $$150 kJ of $$heat to the surroundings. Which of the following statements is true?

Accepted Answer

The reaction is exothermic.

Question 16

Which of the following is the correct balanced equation for the combustion of methane ($$	ext{CH}_4$$)?

Accepted Answer

$$	ext{CH}_4 + 2	ext{O}_2 ightarrow 	ext{CO}_2 + 2	ext{H}_2	ext{O}$$

Question 17

If $$4.00$$ grams of hydrogen gas ($$	ext{H}_2) $$react with excess oxygen, how many grams of water ($$	ext{H}_2	ext{O}) $$are produced? (Molar mass of $$	ext{H}_2 = 2.02 g/$$mol, $$	ext{H}_2	ext{O} = 18.02 g/$$mol, reaction: $$2	ext{H}_2 + 	ext{O}_2 ightarrow 2	ext{H}_2	ext{O})$$

Accepted Answer

Question 18

Which of the following elements is a nonmetal?

Accepted Answer

Oxygen (O)

Question 19

A gas sample at $$25^\circC $$and $$1.00$$ atm has a volume of $$10.0 L. If $$the temperature is increased to $$50^\circC at $$constant pressure, what is the new volume? (Use the ideal gas law and assume Kelvin temperatures.)

Accepted Answer

$$10.8 L$$

Introduction to Chemistry: Course Objectives and Key Concepts

Study Guide - Practice Questions

Study Guide - Flashcards