Molar Mass and Percent Composition

What is the molar mass of water (H2O)?

• 18.02g/mol

• 17.01g/mol

• 16g/mol

• 1.01g/mol

Find the percent composition of Cu₂S?

• %Cu= 67.987 %S= 32.013

• %Cu= 79.854   %S= 20.145

• %Cu= 35.946   %S= 64.054

What is the Molar Mass of Platinum (Pt)?

• 195.08 g/mol

• 78 g/mol

• 106.4 g/mol

• 145 g/mol

What is the molar mass of Oxygen?

• 8 grams

• 8 moles

• 15.999 grams

• 15.999 moles

Tags

NGSS.HS-PS1-1

What is the percent composition of chlorine in sodium chloride (NaCl)? (Atomic masses: Na = 22.99 g/mol, Cl = 35.45 g/mol)

• 60.66%

• 39.34%

• 50.50%

• 49.50%

Tags

DOK Level 2: Skill/Concept

What is the percent composition of the element hydrogen in the compound methane, CH₄?

• 16.0%

• 25.1%

• 74.9%

• 100.0%

What is the approximate percent by mass of magnesium in MgO?

• 20%

• 40%

• 50%

• 60%

What is the percent by mass of magnesium in MgO?

• 20%

• 40%

• 50%

• 60%

Tags

NGSS.HS-PS1-7

What is the equation for calculating percent composition?

• mass of element/mass of compound = x 100

• mass of compound/mass of element = x 100 

• total mass/molar mass = x 100 

• molar mass/molar mass = x 100 

Find the percent composition of Aspirin C9H8O4?

• 180 g/mol

• Molar Mass of C9

• 4.4%

• H

• 35.6%

• C

• 108 g/mol

• Molar Mass of Aspirin

• 60%

• O