Question 1

Which of the following best describes a chemical change?

Accepted Answer

Iron rusting in moist air

Question 2

A student measures the mass of a sample as 12.30 g and its volume as 4.1 mL. What is the density of the sample, reported with the correct number of significant figures?

Accepted Answer

$$3.0\ \mathrm{g/mL}$$

Question 3

Which of the following is a homogeneous mixture?

Accepted Answer

Salt water

Question 4

Which statement about the scientific method is correct?

Accepted Answer

Experiments are designed to test hypotheses.

Question 5

Which of the following elements is a noble gas?

Accepted Answer

Neon ($$\mathrm{Ne})$$

Question 6

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

Accepted Answer

$$0.500\ \mathrm{mol}$$

Question 7

Which of the following best explains why metals are good conductors of electricity?

Accepted Answer

They have loosely held valence electrons that can move freely.

Question 8

Which of the following is the correct electron configuration for a neutral atom of magnesium ($$\mathrm{Mg}$$, atomic number 12)?

Accepted Answer

$$1s^2$$\ $$2s^2$$\ $$2p^6$$\ $$3s^2$$

Question 9

Which of the following compounds is named correctly?

Accepted Answer

NaCl: sodium chloride

Question 10

A 5.00 g sample of a compound contains 2.00 g of carbon, 0.33 g of hydrogen, and 2.67 g of oxygen. What is the empirical formula of the compound?

Accepted Answer

$$\mathrm{CH_2O}$$

Question 11

Which of the following statements about isotopes is correct?

Accepted Answer

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

Question 12

Which of the following is an example of an exothermic process?

Accepted Answer

Water freezing

Question 13

Which of the following best describes the law of conservation of mass?

Accepted Answer

The total mass of reactants equals the total mass of products in a chemical reaction.

Question 14

Which of the following is the correct formula for the compound formed between aluminum and oxygen?

Accepted Answer

$$\mathrm{Al_2O_3}$$

Question 15

A student needs to convert $$5.0\ \mathrm{cm^3$} to$$ $$\mathrm{mL}. $$What is the correct answer?

Accepted Answer

$$5.0\ \mathrm{mL}$$

Question 16

Which of the following best explains why the atomic radius decreases across a period from left to right?

Accepted Answer

The number of protons increases, pulling electrons closer to the nucleus.

Question 17

Which of the following is the correct name for $$\mathrm{H_2SO_4}$$?

Accepted Answer

Sulfuric acid

Question 18

A sample of gold ($$\mathrm{Au}) $$has a mass of $$19.7\ \mathrm{g}. $$How many moles of gold are present? (Molar mass of $$\mathrm{Au} is$$ $$197\ \mathrm{g/mol})$$

Accepted Answer

$$0.10\ \mathrm{mol}$$

Question 19

Which of the following is a physical property?

Accepted Answer

Density

Question 20

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.

Introductory Chemistry Midterm Review Study Notes

Guida di studio - Domande di pratica

Study guide - Flashcard