unit 9 practice

What is Avogadro's number?

• 6.02 x 10²³

• 1 mole

• 600 million

• 6.02

How many moles are in 8.30 X 10²³ molecules of H₂O?

• 1.38 X 10²³ moles H₂O

• 1.38 moles H₂O

• 2 moles H₂O

• 1 mole H₂O

How many molecules are there in 31.8 moles of water?

• 5.28 x 10^-23 molecules

• 1.91 x 10²⁵ molecules

• 5.28x 10^-25 molecules

• 1.91 x 10²³ molecules

Why is the mole used in chemistry?

• The mass of atoms is in AMUs which is too hard to convert to grams.

• A dozen is not a scientific amount.

• Chemists needed to make chemistry easier to understand.

• It makes counting large numbers of small particles easier.

Find the Molar Mass of:
Ga₂(SO₃)₃

• 280 g/mol
• 400 g/mol
• 380 g/mol
• 480 g/mol

How many atoms are in 1.50 moles of Hg?

• 9.03x10²³ atoms Hg
• 9.03x10²⁴ atoms Hg
• 903 atoms of Hg
• 9.03 atoms of Hg

Determine the molar mass for CCl₄

• 153.8 g/mol
• 47.54 g/mol
• 189.35 g/mol
• 82.9 g/mol

What is the molar mass of (NH₄)₂CO₃?

• 144g

• 138g

• 96g

• 78g

What is the mass in grams of 5.90 mol C₈H₁₈?

• 0.0512g

• 19.4g

• 389g

• 673g

What is the percent composition of barium in BaCrO₄?

• 20.5%

• 54.2%

• 25.26%

• 66.88%