Kennedy-- stoichiometry multistep conversion lesson

Stoichiometry: multi-step conversions

Chemists use mole ratios to convert between units of different substances. These numbers come from the coefficients in a balanced equation.

Mole Ratio conversions

Multiple Choice

What is the correct mole ratio of CH₄ to Cl₂ in the equation shown?

• 1:1
• 4:1

• 4:2

• 1:4

Multiple Choice

What is the correct mole ratio of CH₄ to CCl₄ in the equation shown?

• 4:1

• 1:2
• 1:1
• 2:1

Multiple Choice

How many moles of Cl₂ can be produced from 2.5 moles of CH₄?

(Given x mole ratio)

• 2 moles of Cl₂

• 3 moles of Cl₂

• 10 moles of Cl₂

• 4 moles of Cl₂

Multiple Choice

How many moles of CCl₄ will be produced from 2.5 moles of CH₄?

(given x mole ratio)

• 5 moles of CCl₄

• 2.5 moles of CCl₄

• 0.5 moles of CCl₄

• 10 moles of CCl₄

Moles of substance 1 to grams of substance 2

Chemists can use the mole ratio and connect it to the molar mass to do a 2 step conversion.

Step 1: Given x mole ratio
Step 2: number of moles from step #1 x the molar mass of second compound.

​Example problem

How many grams of CCl₄ can be produced from 3.2 moles of Cl₂?

Step 1: Given x mole ratio
3.2 moles Cl₂ x (1 mole CCl₄ / 4 moles Cl₂) = 0.8 moles CCl₄

Step 2: moles CCl₄ from step 1 x molar mass of CCl₄
0.8 moles CCl₄ x 153.81 g/mol CCl₄ = 123.05 grams CCl₄

Drag and Drop

CH₄ + 4 Cl₂ --> CCl₄ + 4 HCl



How many grams of HCl can be produced from 2.25 moles CH₄?

Drag and drop the values to show the correct set up to solve this problem.

Step 1: ​

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x ​

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= ​

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Step 2: 10 moles HCl x ​

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= ​

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Drag these tiles and drop them in the correct blank above

2.25 moles CH4

4 moles HCl / 1 moles CH4

10 moles HCl

36.46 g/mol HCl

366 grams HCl

Multiple Choice

CH₄ + 4 Cl₂ --> CCl₄ + 4 HCl

How many grams of HCl can be produced from 5.0 moles of CH₄?

step 1: given moles CH₄ x mole ratio = moles HCl

step 2: number of moles HCl from step 1 x molar mass of HCl = grams HCl

• 729.2 grams of HCl
• 500 grams of HCl
• 107.4 grams of HCl

• 256.8 grams of HCl

Multiple Choice

CH₄ + 4 Cl₂ --> CCl₄ + 4 HCl

How many grams of CCl₄ can be produced from 5.0 moles of CH₄?

step 1: given moles CH₄ x mole ratio = moles CCl₄

step 2: number of moles CCl₄ from step 1 x molar mass of CCl₄ = grams CCl₄

• 106.9 grams

• 769.1 grams
• 520.9 grams

• 300.5 grams

Multiple Choice

CH₄ + 4 Cl₂ --> CCl₄ + 4 HCl

How many grams of HCl can be produced from 5.0 moles of Cl₂?

step 1: given moles Cl₂ x mole ratio = moles HCl

step 2: number of moles HCl from step 1 x molar mass of HCl = grams HCl

• 276.9 grams of HCl

• 150.5 grams of HCl
• 182.3 grams of HCl
• 75.02 grams of HCl

Grams of substance 1 to grams of substance 2

​Example problem

Multiple Choice

CH₄ + 4 Cl₂ --> CCl₄ + 4 HCl

How many grams of HCl can be produced from 60 grams of CH₄?

Step 1: given amount of grams CH₄ $$\div$$ molar mass of CH₄ = moles of CH₄

Step 2: moles CH₄ from step 1 x mole ratio = moles of HCl

Step 3: number of moles HCl from step 3 x molar mass of HCl

• 710.3 g

• 450.9 g

• 363.0 g

• 545.2 g

Multiple Choice

CH₄ + 4 Cl₂ --> CCl₄ + 4 HCl

How many grams of CCl₄ can be produced from 60 grams of CH₄?

Step 1: given amount of grams CH₄ $$\div$$ molar mass of CH₄ = moles of CH₄

Step 2: moles CH₄ from step 1 x mole ratio = moles of CCl₄

Step 3: number of moles CCl₄ from step 3 x molar mass of CCl₄

• 105 g

• 250 g

• 575 g

• 450 g

Multiple Choice

CH₄ + 4 Cl₂ --> CCl₄ + 4 HCl

How many grams of HCl can be produced from 25 grams of Cl₂?

Step 1: given amount of grams Cl₂ $$\div$$ molar mass of Cl₂ = moles of Cl₂

Step 2: moles Cl₂ from step 1 x mole ratio = moles of HCl

Step 3: number of moles HCl from step 3 x molar mass of HCl

• 8.25 grams
• 12.85 grams
• 15.17 grams

• 10.53 grams

-Ms. Kennedy

All done! Way to go!