Calculating Percent Composition

What is the percent by mass of magnesium in MgO?

• 20%

• 40%

• 50%

• 60%

Tags

NGSS.HS-PS1-7

What is the percent by mass of chlorine in NaCl?

• 39%

• 61%

• 35%

• 35%

What is the percent by mass of fluorine in CaF₂ (gram-formula mass = 78 g/mol)?

• 24%

• 49%

• 49%

• 65%

What is the percent by mass of calcium in CaF₂ (gram-formula mass = 78 g/mol)?

• 24%

• 49%

• 51%

• 65%

Find the percent composition of Cu₂S?

• %Cu= 67.987 %S= 32.013

• %Cu= 79.854 %S= 20.145

• %Cu= 35.946 %S= 64.054

Which element in the compound potassium cyanide, KCN, has a percent composition of 60.97%?

• K

• C

• N

• None

Which of the following is NOT needed to calculate percent composition?

• Mass of specific element

• Molar Mass

• Avogadro's Number

• Division

What is the percent composition of hydrogen in methane, CH₄? (Round to the nearest whole number.)

• 4%

• 25%

• 75%

• 80%

Find the percent composition of N₂S₂.

• N: 69.6%  S: 30.4%

• N:36% S: 75.6%

• N: 96.6% S: 3.4%

• N: 30.4% S: 69.6%

What is the percent by mass of oxygen in H2O?

• 11%

• 33%

• 67%

• 89%