Percent Composition

Carbon monoxide, a deadly gas, has a chemical formula of CO (one carbon atom with one oxygen atom). If you look at the total atomic mass of CO, does carbon or oxygen make up more of the mass?

• carbon

• oxygen

• they are exactly the same

• it is impossible to tell

Tags

NGSS.MS-PS1-1

What percentage of the total atomic mass of carbon monoxide (CO) is composed of carbon?

• 29%

• 43%

• 57%

• 73%

Tags

NGSS.HS-PS1-7

What percentage of the total atomic mass of carbon monoxide (CO) is composed of oxygen?

• 29%

• 43%

• 57%

• 73%

Magnesium bromide (one magnesium atom with two bromine atoms) has a chemical formula of MgBr₂. If you look at the total atomic mass of MgBr₂, does magnesium or bromine make up more of the mass?

• bromine

• magnesium

• they are exactly the same

• it is impossible to tell

Tags

NGSS.MS-PS1-1

What percentage of the total atomic mass of magnesium bromide (MgBr₂) is composed of magnesium?

• 13%

• 43%

• 63%

• 87%

What percentage of the total atomic mass of magnesium bromide (MgBr₂) is composed of bromine? Hint - consider the mass of both atoms of bromine in your calculation.

• 13%

• 43%

• 63%

• 87%

Tags

NGSS.HS-PS1-7

Lithium phosphide (three lithium atoms with one phosphorus atom) has a chemical formula of Li₃P. If you look at the total atomic mass of Li₃P, does lithium or phosphorus make up more of the mass?

• lithium

• phosphorus

• they are exactly the same

• it is impossible to tell

What percentage of the total atomic mass of lithium phosphide (Li₃P) is composed of lithium? Hint - consider all three atoms of lithium in your calculation.

• 13%

• 29%

• 40%

• 60%

What percentage of the total atomic mass of lithium phosphide (Li₃P) is composed of phosphorus?

• 13%

• 29%

• 40%

• 60%

What percentage of the total atomic mass of calcium nitrate (Ca(NO₃)₂) is composed of nitrogen? Hint - another way to think of calcium nitrate is Ca(NO₃)(NO₃).

• 17%

• 24%

• 29%

• 59%