Unit 7.1 Moles & Molar Mass Review

Unit 7.1 Moles & Molar Mass Review

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Multiple Choice

How many particles are in a mole?

• 6022

• 6022 million

• 6022 moles

• 6.022 x 10²³

1 Mole = 6.022 x 10²³

You need to have this number memorized!

Multiple Choice

How many water molecules are in 5.2 moles of water?

• 6.02 x 10²³
• 5.2
• 3.1 x 10²⁴

• 8.6 x 10^-24

When a question is asking for water molecules, the answer will be a very large number.

Multiple Choice

How many water molecules are in 1.2 moles of water?

• 1.9 x 10²³

• 1.9 x 10^-24

• 7.2 x 10²³

• 7.2 x 10^-24

Watch the Video linked to Schoology to the 2:00 mark to assist you with the last problem.

https://www.youtube.com/watch?v=kJQnOVk8k2A

Multiple Choice

How many moles of Francium (Fr) are in 7.4 x 10²⁶ atoms?

• 1.23 moles

• 45 x 10⁴⁹ moles

• 87 moles

• 1.2 x 10³ moles Fr

Multiple Choice

How many moles are in 4.5x10²⁴ particles?

• 0.75 particles

• 0.75 mol

• 2.7 x10⁴⁷ mol

• 2.7 x10⁴⁷ particles

Remember to divide by (6.022 x 10²³) when given molecules/particles!

Multiple Choice

How many moles are in 3.7 x 10²⁰ Sodium (Na) atoms?

• 6.1 x 10^-4

• 2.2 x 10⁴⁴

• 2.2 x 10⁴

• 6.1 x 10⁴⁴

Continue the video from the 2 minute mark to the finish for assistance with the last problem.

https://www.youtube.com/watch?v=kJQnOVk8k2A

Multiple Choice

In 2 moles of Ammonia NH₄ there are 1.20 x 10²⁴ molecules of ammonia. How many total atoms of Nitrogen are there in 2 moles of Ammonia?

• 1

• 1.20 x 10²⁴

• 1.20 x 10^-24

• 6.022 x 10²³

In 2 moles of Ammonia (NH₄) there are 1.20 x 10²⁴ molecules of ammonia. How many total atoms of Nitrogen are there in 2 moles of Ammonia?

These question are asking for the total number of atoms (still a BIG number) of a specific atom of a compound. So, in 1.24 x 10²⁴ ammonia molecules, how many Nitrogen atoms are there? In order to find the number of Nitrogen atoms, multiply the total number of ammonia molecules by how many Nitrogen atoms there are in one ammonia.

(1.20 x 10²⁴) x (1) = 1.20 x 10²⁴

Multiple Choice

In 2 moles of Ammonia (NH₄) there are 1.20 x 10²⁴ molecules of ammonia. How many total atoms of Hydrogen are there in 2 moles of Ammonia?

• 4.80 x 10²⁴

• 6.022 x 10²³

• 3.00 x 10²³

• 1.80 x 10^-24

Multiple Choice

What is the molar mass of AuCl₃?

• 96 g/mol

• 130 g/mol

• 232.5 g/mol

• 303.3 g/mol

Multiple Choice

Calculate the molar mass of Ba(C₂H₃O₂)₂

• 255.3 g/mol

• 237.3 g/mol

• 228.3 g/mol

• 196.3 g/mol

Multiple Choice

What is the molar mass of CO₂?

• 12 g/mol

• 16 g/mol

• 32 g/mol

• 44 g/mol

Confused about Molar Mass? Look at yesterday's (Unit 7.2) slides and/or look at the video linked below.

https://www.youtube.com/watch?v=o3MMBO8WxjY