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Kelso High-Chem H-Mole to mass mass to mole problems

Last updated almost 5 years ago
14 questions
To convert moles to grams and grams to moles, you'll need the molar mass of each compound. The amount of the substance that is known will be multiplied by a conversion factor (a fraction of equal amounts) that will allow the given units to be cancelled out. Molar mass, or grams/mole, is a conversion factor.

If you are converting moles to mass, moles are the given unit and your fraction has the formula mass in grams in the numerator (top) and 1 mole in the denominator (bottom). Essentially you are multiplying by the value of molar mass and changing the unit to grams.

If you are converting mass to moles, your mass has to be converted into grams first. Then grams are your starting unit and your fraction has 1 mole in the numerator (top) and the mass in grams in the denominator (bottom). Essentially you are dividing by the value of the molar mass and changing the unit to mol.

However, since this is a skill that will build, practice writing out the problem in the show your work. (These skills will be the two ends of a stoichiometry problem that should be written out.)
Convert the following mole amounts into grams of that substance. Make sure to identify your number with the correct unit symbol.
1

2.7 mol dinitrogen tetrahydride, N2H4

1

1.1 mol sodium chlorate, NaClO

1

5.0 mol calcium sulfate, CaSO4

Convert the following masses into the equivalent moles of the substance. Remember to include the correct unit symbol.
1

96.3 g of calcium sulfate, CaSO4

1

123.2 g of cobalt (II) phosphate, Co3(PO4)2

1

2.7 kg of gypsum, CaSO4 x 2 H2O

Part of problem solving is understanding what the question is asking. Read the problem to determine what conversion you are needing to make, what process you will need to make it, and what units your answer should be in.
1

How many moles are in 49.4 grams of sodium sulfite, NaSO3?

1

37.9 grams of copper sulfate pentahydrate, CuSO4 x 5 H2O contains how many moles?

1

An experiment calls for 1.0 moles of diethyle ether, (C2H5)2O. How many grams should the student measure out?

1

The number of moles in a 12.61 gram sample of putrescine, C4H12N2 would be...?

1

How many grams does a 0.640 mol sample of boric acid, H3BO3 weigh?

1

How many grams in a 0.44 mol sample of glucose, C6H12O6?

1

A 96.3 gram sample of caffeine would contain how many moles?

1

How many grams in a 2.20 mol sample of ethanol, C2H6O?