Chem Review S2 Unit 9 & 10

Chem Review S2 Unit 9: The Mole & 10: Stoich

By Ricardo Mora

In this unit, you learned how to calculate the molar mass of a compound. You also learned how to go from gram to mole and mole to gram.

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Unit 9: The Mole

Calculating Molar Mass of a Compound

• Determine the number of atoms of each element

• Multiply the number of atoms by the atomic mass of each element

• Add the molar masses of each element together for the molar mass of the compound

Multiple Choice

Calculate the Molar Mass of AlBr₃?

• 106.886 grams

• 266.694 grams

• 26.982 grams

• 79.904 grams

Multiple Choice

How many moles is 100 grams of FeCl₂?

• 0.79 moles

• 100 moles

• 126.745 moles

• 7.9 moles

Multiple Choice

What is the empirical formula for C₄H₆?

• CH

• CH₃

• C₂H₃

• C₄H₆

Multiple Choice

You are given 40.05g S and 59.95g O. Find the empirical formula for these elements.

• SO

• SO2

• SO3

• SO4

Multiple Choice

A compound consists of 72.2% magnesium(Mg) and 27.8% nitrogen(N) by mass. What is the empirical formula?

• Mg₄N₃

• MgN₂

• Mg₃N₂

• MgN

Multiple Choice

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

• 16 g
• 24 g
• 32 g
• 48 g

Multiple Choice

Find the molar mass for H₂O

The following is the Atomic Mass from the Period Table

O=16g

H=1g

• 18 g

• 16 g

• 2 g

• 1 g

Multiple Choice

How many moles are in 16.94 g of water?

• 16.94 mol H₂O
• 0.9401 mol H₂O
• 305.3 mol H₂O
• 1.063 mol H₂O

Multiple Choice

How many moles is 19.5 grams of Sodium?

• 19.5 moles

• 0.85 moles

• 22.99 moles

• 8.5 moles

Multiple Choice

What is Avegadro's number?

• 1 mole

• 6.02 X 10²³

• 1 gram

• 10 m

Multiple Choice

Calculate how many moles are in 13.0 grams of NaOH?

Remember Molar Mass of NaOH= 40 g

• 325 moles

• 0.520 moles

• 520 moles

• .0325 moles

Multiple Choice

Calculate how many grams are in 5.6 moles of H2O:

What are you giving?

• grams

• moles

• molecules

• atoms

In this unit, you learned how to calculate gram to gram calculations and other calculations using the BCE. (Balanced Chemical Equation)

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Unit 10: Stoichiometry

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Multiple Choice

In the formation of ammonia,

N₂ + 3H₂ → 2NH_3,

_{What is the mole ratio of hydrogen to nitrogen?}

• 3:2

• 1:3

• 3:1

• 2:3

Multiple Choice

4K_(s) + O_2(g) → 2 K₂O_(s)

If a staff member at a laboratory has 12.0 grams of potassium metal, what is the theoretical yield of potassium oxide that the scientist could potentially produce from the reaction with oxygen gas?

• 9.96 g

• 14.5 g

• 28.9 g

• 57.8 g

Multiple Choice

Which of the following is true of a limiting reagent?

I.   It is a reactant

II.  It limits the amount of product formed

III. It determines the maximum amount of product formed.

• I

• II

• I & II

• I, II, & III

Multiple Choice

4Al (s) + 3O₂ (g) → 2Al₂O₃ (s)

 

What mass of aluminum oxide (Al₂O₃) can be produced from the reaction of 30.5 g of aluminum with 46.2 g of oxygen?

• 10.2 g

• 32.4 g

• 57.6 g

• 46.2 g

Multiple Choice

N₂ + 3H₂ --> 2NH₃
How many moles of N₂ is needed to react with 6 moles of H₂?

• 6.7
• 2.0
• 3.0
• 15.0

Multiple Choice

H₂+Cl₂-->2HCl
What is the total number of moles of HCl produced when 3 moles of H₂ is completely consumed?

• 5
• 2
• 3
• 6

Multiple Choice

4NH₃ + 5O₂-->4NO + 6H₂O
What is the total number of moles of H₂O produced when 12 mole of NH₃ is completely consumed?

• 15
• 18
• 20
• 24

Multiple Choice

6CO₂ + 6H₂O --> C₆H₁₂O₆ + 6O₂ 
What is the total number of moles of CO₂ needed to make 2 moles of C₆H₁₂O₆?

• 2.5
• 6
• 12
• 15

Multiple Choice

Determine the molar mass for carbon tetrachloride (CCl₄)

• 153.823 g/mol

• 118.37 g/mol

• 189.35 g/mol

• 47.464 g/mol

Multiple Choice

Given the equation:

2NaClO₃ (s) → 2NaCl (s) + 3O₂ (g)

When 2.00 moles of NaClO₃ react, how many grams of O₂ is produced?

• 56 g of O₂

• 96 g of O₂

• 64 g O₂

• 32 g O₂

Multiple Choice

CH₄ + 2 O₂ → CO₂ + 2 H₂O
How many moles of carbon dioxide are produced from the combustion of 110 g of CH₄?

• 13.7 mol
• 2.75 mol
• 6.11 mol
• 6.85 mol

Multiple Choice

What is the percent by mass of magnesium in MgO?

• 20%
• 40%
• 50%
• 60%

Multiple Choice

What is the percent composition by mass of sulfur in the compound MgSO₄ (gram formula mass = 120 g/mol)?

• 20%
• 27%
• 46%
• 53%