Question 1

Which of the following best describes a chemical change?

Accepted Answer

Iron rusting when exposed to air

Question 2

A student measures the mass of a sample as 12.305 g. How many significant figures are in this measurement?

Accepted Answer

5

Question 3

Which of the following is a heterogeneous mixture?

Accepted Answer

Sand and iron filings

Question 4

Which of the following statements about the scientific method is correct?

Accepted Answer

An experiment is designed to test a hypothesis.

Question 5

Convert $$3.45 	imes 10^4$ to standard notation.

Accepted Answer

34,500

Question 6

Which of the following is a chemical property?

Accepted Answer

Reactivity with oxygen

Question 7

A block of metal has a mass of 250 g and a volume of 50.0 mL. What is its density?

Accepted Answer

$$5.0\ \mathrm{g/mL}$$

Question 8

Which of the following best describes an element?

Accepted Answer

A pure substance made of only one kind of atom

Question 9

Which of the following is the correct scientific notation for 0.00056?

Accepted Answer

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

Question 10

Which of the following is a physical change?

Accepted Answer

Dissolving sugar in water

Question 11

A sample contains 3.00 moles of water. What is the mass of the sample? (Molar mass of water = $$18.0\ \mathrm{g/mol})$$

Accepted Answer

$$54.0\ \mathrm{g}$$

Question 12

Which of the following is a correct statement about exothermic and endothermic processes?

Accepted Answer

Exothermic processes release heat to the surroundings.

Question 13

Which of the following is the correct number of significant figures in the measurement 0.00450?

Accepted Answer

3

Question 14

Which of the following best describes a compound?

Accepted Answer

A pure substance composed of two or more elements chemically combined in a fixed ratio

Question 15

A student adds 2.50 g of salt to 47.5 g of water. What is the total mass of the solution, and how many significant figures should the answer have?

Accepted Answer

50.0 g, 3 significant figures

Question 16

Which of the following is a correct example of a physical property?

Accepted Answer

Boiling point

Question 17

Which of the following is the correct metric prefix for $$10^{-3}$$?

Accepted Answer

milli-

Question 18

Which of the following best explains the difference between a pure substance and a mixture?

Accepted Answer

A mixture has a variable composition, while a pure substance has a fixed composition.

Question 19

Which of the following is the correct formula for density?

Accepted Answer

$$\mathrm{Density} = \dfrac{\mathrm{mass}}{\mathrm{volume}}$$

Question 20

Which of the following is a correct example of a homogeneous mixture?

Accepted Answer

Salt dissolved in water

Introduction to Chemistry: Core Concepts and Study Guide

Guida di studio - Domande di pratica