Chem R Math of Chemistry Test Prep Quizziz

A compound was analyzed and found to contain 75% carbon and 25% hydrogen by mass. What is the compound's empirical formula?

• CH

• CH₂

• CH₃

• CH₄

What is the formula mass of Al₂(SO₄)₃?

• 
  123

• 150

• 214

• 342

What is the percent composition by mass of nitrogen in the compound N₂H₄ (gram-formula mass = 32 g/mol)?

• 13%

• 44%

• 88%

• 
  93%

What is the percent composition by mass of nitrogen in (NH₄)₂CO₃ (gram-formula mass = 96.0 g/mol)?

• 
  14.6%

• 29.2%

• 58.4%

• 
  87.5%

• 1.0 mol

• 2.0 mol

• 3.0 mol

• 4.0 mol

Given the balanced equation representing a reaction:

C₃H₈(g) +5O₂(g) 3CO₂(g) + 4H₂O(g)

What is the total number of moles of O₂(g) required for the complete combustion of 1.5 moles of C₃H₈(g)?

• .30 mol

• 
  1.5 mol

• 
  4.5 mol

• 
  7.5 mol

What is the total number of atoms contained in a 1.00-mole sample of helium?

• 1.00 atom

• 
  2.00 atoms

• 1.20 × 10²⁴ atoms

• 
  6.02 × 10²³ atoms

What is the total number of neon atoms contained in 20.2 grams of neon gas?

• 1.01 × 10²⁴

• 2.02 × 10²⁴

• 3.01 × 10²³

• 6.02 × 10²³

Which formula is the empirical formula for ethane, C₂H₆?

• CH

• CH₃

• 
  C₂H₆

• C₄H₁₂

Which term represents the simplest whole number ratio of atoms of the elements in a compound?

• atomic mass

• formula mass

• empirical formula

• structural formula