7th Grade Chemistry Review!

Question 1

If you leave copper in air, it has a slow chemical reaction. The original shiny copper metal is a:

Accepted Answer

reactant

Question 2

In a lab, we could mix copper with a strong acid and make CuCl2. Which WOULD NOT happen in the reaction?

Accepted Answer

New elements are made

Question 3

This picture shows bronze, a metal alloy made with copper and tin. Alloys are mixtures. This means:

Accepted Answer

The atoms are NOT bonded together.

Question 4

The chemical equation for brown pennies is 2Cu + O2 --> 2CuO. The abbreviation 2CuO means:

Accepted Answer

2 molecules, each with 1 copper atom and 1 oxygen atom

Question 5

The brown-penny chemical is CuO. How many bonds are in this molecule?

Accepted Answer

2

Question 6

What is the chemical formula for the copper carbonate from that reaction?

Accepted Answer

CuCO3

Question 7

Cu + ?HCl --> CuCl2 + H2 shows the reaction of copper and acid. Fill in the ? to balance the equation.

Accepted Answer

2

Question 8

Pennies left outside can also react with carbon dioxide, CO2, in the air. How many atoms are in CO2?

Accepted Answer

3

Question 9

The chemical equation for brown pennies is 2Cu + O2 --> 2CuO. The abbreviation O2 means:

Accepted Answer

A molecule with two bonded oxygen atoms

Question 10

Copper atoms can join with other atoms to make molecules. How many atoms does this molecule have?

Accepted Answer

9

Question 11

Cu + ?HCl --> CuCl2 + H2 is the chemical equation for the reaction of copper and acid. Which particle is this?

Accepted Answer

The HCl reactant

Question 12

All chemical reactions include:

Accepted Answer

Chemical bonds of molecules breaking

Question 13

Copper atoms can join with other atoms to make molecules. How many bonds does this molecule have?

Accepted Answer

12

Question 14

This picture shows bronze, a metal alloy made with copper and tin. Which atom has a greater atomic mass?

Accepted Answer

The tin atom

Question 15

Somebody weighed this copper and it had a mass of 18 grams. It takes up 2 cubic cm of space. What's its density?

Accepted Answer

9 grams per cubic centimeter

Question 16

If you leave copper in air, it has a slow chemical reaction. The brown chemical is a:

Accepted Answer

product

Question 17

The brown-penny chemical is CuO. How many atoms are in this molecule?

Accepted Answer

2

Question 18

The green-penny reaction product is called copper carbonate. The copper carbonate molecules come from...

Accepted Answer

the reactant atoms rearranging

Question 19

Pennies left outside can also react with carbon dioxide, CO2, in the air. How many elements are in CO2?

Accepted Answer

2

Question 20

Here is some copper mined from the Earth. It has only atoms of copper. It is:

Accepted Answer

An element

Questions 20