Moles Conversion Pratice Problem

Brief Explaination

The skill of converting from grams to moles to molecules is needed for problems later that would require this type of math problem as a step in solving the whole problem such as molarity and mass-mass problems.

In the conversion of moles to grams, you need to multiply the moles with the molar mass to get the grams of a substance. In the conversion of grams to moles, you divide the grams of the substance by the molar mass to determine the moles. In the conversion of moles to molecules, you need to multiply the moles with the Avogadro’s constant, Avogadro's number, which is 6.02 x 10²³ . To determine the moles of a substance with the molecules, you divide the molecules with the Avogadro’s constant.

Pratice Problems

1. How many moles are represented by 16.0 g of ethanol, C₂H₅OH ?

2. How many grams of glucose are in 6.63 x 10²³ molecules of glucose, C₆H₁₂O₆?

3. How many moles of methanol, CH3OH, are there in 6.53 x 10²³ molecules of methanol?

4. How many moles of NaCl are in 16.0 grams of NaCl?

5.How many molecules of potassium hydroxide, KOH are in 40.6 g?

6. How many grams of glucose, C₆H₁₂O₆ are in 6.63 x 10²³ molecules of glucose?

Answers

1. .347 moles of C₂H₅OH

2. 198 grams of glucose

3. 1.08 moles of methanol

4. .27 moles of NaCl

5. 4.33 x 10²³ molecules of K

6. 198 grams of glucose

Links

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Need a more through explaination for the conversions, click here

If you do not know the rules in rounding to significiant digit, click here