Question 1

Which of the following best describes a key difference between the early practice of chemistry (alchemy) and the modern practice of chemistry?

Accepted Answer

Early chemistry was primarily concerned with the transformation of base metals into gold, while modern chemistry is based on empirical evidence and the scientific method.

Question 2

Which of the following is NOT a step in the scientific method?

Accepted Answer

Ignoring data that does not fit the hypothesis

Question 3

A student measures the length of a metal rod three times and records the values as 12.34 cm, 12.35 cm, and 12.33 cm. Which of the following best explains why these measurements are not exact?

Accepted Answer

The measuring instrument has limitations and human error can occur, so all measurements have some degree of uncertainty.

Question 4

Which of the following correctly expresses the number 0.00056 in scientific notation?

Accepted Answer

$$5.6 	imes 10$$^{-4}$$

Question 5

A sample of a metal has a mass of 45.0 g and a volume of 15.0 mL. What is its density?

Accepted Answer

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

Question 6

Convert 250 milliliters (mL) to liters (L).

Accepted Answer

$$0.25\ \mathrm{L}$$

Question 7

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

Accepted Answer

Groups are vertical columns and periods are horizontal rows.

Question 8

Which of the following elements is a nonmetal at room temperature and is found as a diatomic molecule in nature?

Accepted Answer

Oxygen ($$\mathrm{O}_2)$$

Question 9

A compound has the empirical formula $$\mathrm{CH}_2\mathrm{O}$$ and a molar mass of $$180\ \mathrm{g/mol}. $$What is its molecular formula?

Accepted Answer

$$\mathrm{C}_6\mathrm{H}_{12}\mathrm{O}_6$$

Question 10

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

Accepted Answer

$$2\mathrm{Na} + 2\mathrm{H}_2\mathrm{O} \rightarrow 2\mathrm{NaOH} + \mathrm{H}_2$$

Question 11

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 12

Which of the following is the correct electron configuration for the element magnesium ($$Z=12$$)?

Accepted Answer

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

Question 13

Which of the following is a correct statement about the relationship between wavelength ($$\lambda$$), frequency ($$
u$$), and the speed of light ($$c$$)?

Accepted Answer

$$c = \lambda 
u$$

Question 14

Which of the following is a property of metals?

Accepted Answer

They are good conductors of heat and electricity.

Question 15

Which of the following is the correct formula for the compound formed between calcium ions and nitrate ions?

Accepted Answer

$$\mathrm{Ca(NO_3$)_2}$$

Question 16

A sample contains $$1.204 	imes 10$$^{24}$$ molecules of water. How many moles of water does this represent? (Avogadro's number = 6.02$$ 	imes $$10^{23})$$

Accepted Answer

$$2.00$$ moles

Question 17

Which of the following is a physical change?

Accepted Answer

Melting of ice

Question 18

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

Accepted Answer

Sulfuric acid

Question 19

Which of the following best describes the trend in atomic size across a period from left to right in the periodic table?

Accepted Answer

Atomic size decreases from left to right.

Question 20

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

Accepted Answer

$$\mathrm{CH_2O}$$

Introductory Chemistry: Comprehensive Study Guide and Learning Objectives

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