Two Step Mole Conversions

I use molar mass to convert to moles when the problem gives me grams?

• False

• True

How do I convert from moles to grams?

• multiply by molar mass

• divide by molar mass

• multiply by Avogadro's number

• divided by Avogadro's number

How many grams of potassium chloride can be produced from 356 grams potassium bromide?

• 749 g

• 225 g

• 479 g

• 814 g

Tags

NGSS.HS-PS1-7

2 C₂H₆ + 7 O₂ → 4 CO₂ + 6 H₂O

A problem asks how many moles of oxygen gas are needed to react completely with 6 moles of ethane (C₂H₆). What is the second step in setting up the problem?

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Tags

NGSS.HS-PS1-7

C₂H₆ + 7 O₂ → 4 CO₂ + 6 H₂O. A problem asks how many moles of oxygen gas are needed to react completely with 6 moles of ethane (C₂H₆). What is the final answer for this problem?

• 13 mol C₂H₆

• 3 mol O₂

• 21 mol O₂

• 42 mol O₂

Tags

NGSS.HS-PS1-7

Where are the numbers for a mole ratio found?

• They are part of the chemical formulas for the reactants / products.

• They are given in the problem.

• They are found on the periodic table for those elements.

• They are found as coefficients in the reaction's balanced chemical equation.

What is the first step in a two-step mole conversion when given grams of a substance?

• Convert grams to moles using molar mass

• Convert moles to molecules using Avogadro's number

• Convert grams to liters using density

• Convert moles to grams using molar mass

If you have 3 moles of a substance, what is the second step to find the number of molecules?

• Multiply by Avogadro's number

• Divide by Avogadro's number

• Multiply by molar mass

• Divide by molar mass

How do you convert 50 grams of a substance to moles?

• Divide by the molar mass

• Multiply by the molar mass

• Multiply by Avogadro's number

• Divide by Avogadro's number

What is the molar mass of water (H2O)?

• 18 g/mol

• 16 g/mol

• 20 g/mol

• 22 g/mol