Assessment #5: Conversions

The gram formula mass (molar mass) of NH₄Cl is

• 22.4 g/mol

• 28.0 g/mol

• 53.5 g/mol

• 95.5 g/mol

Which quantity is equivalent to 39 grams of LiF?

• 1.0 mole

• 0.50 moles

• 2.0 moles

• 1.5 moles

What is the molar mass of potassium carbonate, K₂CO₃ ?

• 138 g

• 106 g

• 99 g

• 67 g

What is the total mass in grams of 0.75 moles of SO₂?

• 16 g

• 24 g

• 32 g

• 48 g

Which substance has the greatest molar mass?

• H₂O₂

• NO

• CF₄

• I₂

Where are the numbers for a mole ratio found?

• They are part of the chemical formulas for the reactants / products.

• They are given in the problem.

• They are found on the periodic table for those elements.

• They are found as coefficients in the reaction's balanced chemical equation.

2 C₂H₆ + 7 O₂ → 4 CO₂ + 6 H₂O

Ethane (C₂H₆) combusts in the above reaction. What is the mole ratio of ethane to oxygen gas?

• 
• 
• 
• 

2 C₂H₆ + 7 O₂ → 4 CO₂ + 6 H₂O

If 3.5 moles of oxygen gas are used up as ethane combusts completely, how many moles of carbon dioxide are produced?

• 0.5 mol CO₂

• 0.57 mol CO₂

• 2.0 mol CO₂

• 3.0 mol CO₂

• 3.5 mol CO₂

The mass of one mole of an element is equal to

• its atomic number from the periodic table, but in amus.

• its atomic mass from the periodic table, but in amus.

• its atomic mass from the periodic table, but in grams.

• its atomic number from the periodic table, but in grams.

How many formula units (molecules) are in 2.5 moles of NaCl?

• 1.5 x10²⁴ formula units (molecules)

• 1.5 formula units(molecules)

• 4.2 formula units (molecules)

• 4.2 x10^-24 formula units(molecules)