Question 1

A sample of gold is hammered into a thin sheet. Which type of change does this process represent?

Accepted Answer

A physical change, because the gold's composition remains the same.

Question 2

Which of the following best describes a mixture of sand and iron filings?

Accepted Answer

A heterogeneous mixture, because the components can be physically separated and are not uniform.

Question 3

A student measures the mass of a sample three times and gets values of 2.01 g, 2.00 g, and 2.02 g. The true mass is 2.50 g. Which statement is correct?

Accepted Answer

The measurements are precise but not accurate.

Question 4

Which of the following is a pure substance?

Accepted Answer

Carbon dioxide $$\mathrm{CO_2$}$$

Question 5

Which step in the scientific method involves proposing a tentative explanation for an observation?

Accepted Answer

Hypothesis

Question 6

Which of the following best describes the state of matter for oxygen gas at room temperature?

Accepted Answer

Indefinite shape and indefinite volume

Question 7

A student dissolves table salt in water. Which of the following best describes the resulting solution?

Accepted Answer

A homogeneous mixture

Question 8

Which of the following is the correct SI unit for temperature?

Accepted Answer

Kelvin $$\mathrm{K}$$

Question 9

Which law states that matter cannot be created or destroyed in a chemical reaction?

Accepted Answer

Law of Conservation of Matter

Question 10

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

Accepted Answer

Burning wood

Question 11

A 250 mL sample of gasoline is poured into a container. Which statement best describes the behavior of gasoline molecules in the liquid state?

Accepted Answer

They are close together but can flow past one another.

Question 12

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

Accepted Answer

Making a law

Question 13

A sample of water is heated from $$25\ ^\circ \mathrm{C} to$$ $$100\ ^\circ \mathrm{C}. $$Which of the following best describes this process?

Accepted Answer

A physical change, because only the state or temperature changes.

Question 14

Which of the following statements about compounds is correct?

Accepted Answer

Compounds have a constant composition and are chemically combined.

Question 15

A scientist records the following data for the mass of a sample: $$5.12\ \mathrm{g}$$, $$5.13\ \mathrm{g}$$, $$5.11\ \mathrm{g}. $$The actual mass is $$5.50\ \mathrm{g}. $$Which of the following best describes the scientist's measurements?

Accepted Answer

Low accuracy, high precision

Question 16

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

Accepted Answer

Salt water

Question 17

Which of the following best describes the difference between an element and a compound?

Accepted Answer

An element contains only one type of atom, while a compound contains two or more elements chemically combined.

Question 18

A student is asked to classify a sample of milk. Which of the following is the best classification?

Accepted Answer

Homogeneous mixture

Question 19

Which of the following best explains why the mass of a closed system remains constant during a chemical reaction?

Accepted Answer

Matter cannot be created or destroyed, according to the Law of Conservation of Matter.

Question 20

A scientist wants to test the effect of temperature on the rate of a chemical reaction. Which step of the scientific method should she perform after forming a hypothesis?

Accepted Answer

Conduct an experiment

Chapter 1: Introduction to Chemistry – Matter and Measurement

스터디 가이드 - 연습 문제

학습 가이드 - 플래시카드