Unit Test — Unit test

Question 1

Which process is a chemical change?

Revolt · Accepted Answer

loss of atmospheric ozone

Question 2

Which statement is true about an empirical formula?

Revolt · Accepted Answer

It is the simplest ratio of atoms in a formula unit.

Question 3

This formula equation is unbalanced.BaCl2(aq) + Na2CO3(aq) BaCO3(s) + NaCl(aq) Which coefficient should be placed in front of NaCl to balance this equation?

Revolt · Accepted Answer

2

Question 4

During an experiment, Jon exhales through a straw and blows bubbles into a solution. Which observation would most likely indicate that a chemical reaction is occurring?

Revolt · Accepted Answer

The solution becomes cloudy with a white solid.

Question 5

If a substance reacts with oxygen, the chemical reaction is most likely a

Revolt · Accepted Answer

combustion reaction.

Question 6

Iron reacts with oxygen to form iron oxide (rust). Which best describes this statement?

Revolt · Accepted Answer

Iron oxide is formed by rearranging atoms.

Question 7

Sodium combines with water to produce sodium hydroxide and hydrogen gas. Which word equation represents this violent reaction?

Revolt · Accepted Answer

sodium + water sodium hydroxide + hydrogen

Question 8

An unbalanced chemical equation for the reaction of boron fluoride with lithium sulfite is shown below.BF3 + Li2SO3 B2(SO3)3 + LiFWhat is the coefficient of lithium fluoride in the balanced chemical reaction?

Revolt · Accepted Answer

6

Question 9

In which two types of reactions do opposite chemical changes occur?

Revolt · Accepted Answer

synthesis and decomposition

Question 10

What is the percent by mass of water in Na2SO4 • 10H2O?Use .

Revolt · Accepted Answer

55.92%

Unit Test — Unit test Answers

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