U5 Moles COVID final exam review with EF MF math

The number 6.02 x 10²³ is called...

• Obama's number
• Bohr's number
• Trump's number
• Avogadro's number

We use the periodic table to calculate...

• atomic , molecular and molar mass

• number of molecules

• moles

How many moles are in 4.5x10²⁴ particles?

• 0.747 particles
• 0.747 mol
• 2.71x10⁴⁷ mol
• 2.71x10⁴⁷ particles

What is the average atomic mass of silver.

• 106.38649amu

• 107. 8677 g/mol

• 107.8677amu

• 121

What is the approximate percent composition by mass of oxygen in the compound MgSO₄ (Molar Mass = 120.4 g/mol)?

• 20%

• 27%

• 46%

• 53%

You are given the following percentages: 40.05% S and 59.95% O. Find the empirical formula for these elements.

• SO

• SO₂

• SO₃

• SO₄

What is the empirical formula for butane, C₄H_6?

• CH

• CH₃

• C₂H₃

• C₄H₆