Question 1

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

Accepted Answer

A chemical change involves a change in the arrangement of atoms, while a physical change does not.

Question 2

Which of the following is an example of a heterogeneous mixture?

Accepted Answer

Sand and iron filings

Question 3

Which law states that the total mass of reactants equals the total mass of products in a chemical reaction?

Accepted Answer

Law of Conservation of Mass

Question 4

Which of the following statements about isotopes is correct?

Accepted Answer

Isotopes have the same number of protons but different numbers of neutrons.

Question 5

A sample contains 3.0 mol of NaCl. How many formula units are present in the sample? (Avogadro's number $$= 6.022 	imes 10$$^{23}$$)

Accepted Answer

$$1.81 	imes 10$$^{24}$$

Question 6

Which of the following electron configurations represents a noble gas?

Accepted Answer

$$1s^2$$ $$2s^2$$ $$2p^6$$

Question 7

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 8

Which of the following molecules is polar?

Accepted Answer

H$$_2O$$

Question 9

What is the correct formula for aluminum sulfate?

Accepted Answer

Al$$_2(SO$_4$$)$$_3$$

Question 10

Which of the following best describes the octet rule?

Accepted Answer

Atoms tend to gain, lose, or share electrons to achieve eight electrons in their valence shell.

Question 11

Which of the following is a correct Lewis structure for methane (CH$$_4$$)?

Accepted Answer

A central C atom with four single bonds to four H atoms.

Question 12

Which of the following best explains why water has a bent molecular geometry?

Accepted Answer

The lone pairs on oxygen repel the bonding pairs, causing a bent shape.

Question 13

Which of the following is the correct balanced equation for the combustion of methane ($$CH_4$$)?

Accepted Answer

$$CH_4 + 2O_2$$ \rightarrow $$CO_2 + 2H_2O$

Question 14

A solution is prepared by dissolving 5.0 g of NaCl in enough water to make 250 mL of solution. What is the molarity of the solution? (Molar mass of NaCl = 58.44 g/mol)

Accepted Answer

$$0.342\ \mathrm{M}$$

Question 15

Which of the following best describes a covalent bond?

Accepted Answer

A bond formed by the sharing of electrons between two nonmetals.

Question 16

Which of the following is a correct statement about electronegativity?

Accepted Answer

Electronegativity increases across a period and decreases down a group.

Chemistry 1: Semester I Final Exam Review – Comprehensive Study Notes

Study Guide - Practice Questions

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