Question 1

Which of the following best describes a heterogeneous mixture?

Accepted Answer

A mixture in which the composition is not uniform and different regions have different properties, such as oil and water.

Question 2

Which of the following is an example of a chemical change?

Accepted Answer

Burning gasoline in a car engine.

Question 3

Which statement correctly distinguishes between an element and a compound?

Accepted Answer

An element consists of only one type of atom, while a compound consists of two or more types of atoms chemically bonded.

Question 4

Which of the following is the correct electron configuration for a neutral oxygen atom?

Accepted Answer

$$1s^2$$\ $$2s^2$$\ $$2p^4$$

Question 5

A student mixes 50.0 mL of 1.00 M NaCl with 150.0 mL of water. What is the final concentration of NaCl in the solution?

Accepted Answer

$$0.25\ \mathrm{M}$$

Question 6

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

Accepted Answer

They consist of ions held together by strong electrostatic forces.

Question 7

Which of the following is the correct balanced equation for the reaction of sodium with water?

Accepted Answer

$$2\mathrm{Na}(s) + 2\mathrm{H}_2\mathrm{O}(l) \rightarrow 2\mathrm{NaOH}(aq) + \mathrm{H}_2(g)$$

Question 8

Which of the following statements about the periodic table is correct?

Accepted Answer

Elements in the same group have the same number of valence electrons.

Question 9

A sample of gas occupies 2.00 L at 1.00 atm and 300 K. What will be its volume at 2.00 atm and 300 K?

Accepted Answer

$$1.00\ \mathrm{L}$$

Question 10

Which of the following is a correct statement about covalent bonding?

Accepted Answer

Covalent bonds involve the sharing of electrons between atoms.

Question 11

Which of the following is the correct formula for ammonium sulfate?

Accepted Answer

$$(NH_4$)_2SO_4$$

Question 12

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

Accepted Answer

A physical property can be measured without changing the identity of the substance, while a chemical property describes the ability of a substance to undergo a specific chemical change.

Question 13

A compound contains 40.0% carbon, 6.7% hydrogen, and 53.3% oxygen by mass. What is its empirical formula?

Accepted Answer

$$CH_2O$$

Question 14

Which of the following is the correct net ionic equation for the reaction between silver nitrate and sodium chloride in aqueous solution?

Accepted Answer

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

Question 15

Which of the following gases will effuse the fastest under identical conditions?

Accepted Answer

$$H_2$$

Question 16

Which of the following is the correct Lewis structure for carbon dioxide ($$CO_2$$)?

Accepted Answer

O=C=O, with each oxygen atom having two lone pairs.

Question 17

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

Accepted Answer

A catalyst lowers the activation energy and increases the rate of reaction without being consumed.

Question 18

A student needs to prepare 250 mL of 0.100 M $$Na_2SO_4$$ solution. How many grams of $$Na_2SO_4$$ are required? (Molar mass of $$Na_2SO_4 = 142\ \mathrm{g/mol})$$

Accepted Answer

$$3.55\ \mathrm{g}$$

Question 19

Which of the following is a correct statement about the ideal gas law?

Accepted Answer

The ideal gas law is given by $$PV = nRT$$, where $$P is $$pressure, $$V is $$volume, $$n is $$moles, $$R is $$the gas constant, and $$T is $$temperature.

CHEM 120: General Chemistry I – Syllabus and Course Overview

Guida di studio - Domande di pratica

Study guide - Flashcard