Pretest

Question 1

Two different liquids are mixed together. Which observation indicates that an exothermic chemical reaction has taken place?

Revolt · Accepted Answer

a rise in temperature

Question 2

Burning a piece of wood in fire can be best described as a

Revolt · Accepted Answer

chemical change because the atoms in wood and oxygen are rearranged.

Question 3

The chemical formula shows how salt is produced. HCl plus NaOH rightarrow NaCl plus cap h sub 2 cap o Which substances are the reactants?

Revolt · Accepted Answer

HCl and NaOH

Question 4

Which term best describes the role of hydrogen gas in the formation of a water molecule?

Revolt · Accepted Answer

reactant

Question 5

Which indicator most likely suggests that a chemical change is taking place?

Revolt · Accepted Answer

change of color

Question 6

A piece of limestone erodes due to acid rain. This process can be best described as a

Revolt · Accepted Answer

slow chemical change.

Question 7

Which statement about a chemical reaction is true?

Revolt · Accepted Answer

It occurs whenever a chemical change takes place.

Question 8

A solid is placed in a solution. Which observation most likely indicates that a chemical reaction has occurred?

Revolt · Accepted Answer

The solid has bubbles forming on its surface.

Question 9

When sodium metal is added to water, an orange flame is observed on the metal surface. Based on this observation, what can best be concluded?

Revolt · Accepted Answer

A chemical reaction occurs because heat and light are given off.

Question 10

Among these processes, which is the slowest chemical reaction?

Revolt · Accepted Answer

tarnishing of silver

Pretest Answers