Q: Which of the following is the correct setup to convert $$75.0\ \mathrm{g} of Ag to $$moles? (Molar mass of Ag = $$107.87\ \mathrm{g/mol})$$

$$75.0\ \mathrm{g} \times \frac{1\ \mathrm{mol}}{107.87\ \mathrm{g}}$$

Question 1

Which of the following best describes the purpose of molar mass in chemical calculations?

Accepted Answer

It is used to convert between the mass of a substance and the number of moles.

Question 2

Given that the molar mass of magnesium (Mg) is $$24.31\ \mathrm{g/mol}$$, how many grams are in $$2.50$$ moles of Mg?

Accepted Answer

$$60.8\ \mathrm{g}$$

Question 3

A jeweler needs $$0.750$$ mole of silver (Ag) for a design. If the molar mass of Ag is $$107.87\ \mathrm{g/mol}$$, how many grams of silver are required?

Accepted Answer

$$80.9\ \mathrm{g}$$

Question 4

A box of salt contains $$737\ \mathrm{g} of $$NaCl. If the molar mass of NaCl is $$58.44\ \mathrm{g/mol}$$, how many moles of NaCl are present?

Accepted Answer

$$12.6\ \mathrm{mol}$$

Question 5

Which of the following conversion factors would you use to convert grams of Mg to moles of Mg?

Accepted Answer

$$\frac{1\ \mathrm{mol\ Mg}}{24.31\ \mathrm{g\ Mg}}$$

Question 6

If you have $$50.0\ \mathrm{g} of $$NaCl, how many moles do you have? (Molar mass of NaCl = $$58.44\ \mathrm{g/mol})$$

Accepted Answer

$$0.856\ \mathrm{mol}$$

Question 7

A chemist needs $$15.0\ \mathrm{g} of $$magnesium for a reaction. How many moles of magnesium does this represent? (Molar mass of Mg = $$24.31\ \mathrm{g/mol})$$

Accepted Answer

$$0.617\ \mathrm{mol}$$

Question 8

Which of the following statements is TRUE about molar mass?

Accepted Answer

Molar mass is the mass of one mole of a substance, expressed in grams per mole.

Question 9

A patient is prescribed a medication that requires $$0.200\ \mathrm{mol} of $$NaCl. How many grams of NaCl should be administered? (Molar mass of NaCl = $$58.44\ \mathrm{g/mol})$$

Accepted Answer

$$11.7\ \mathrm{g}$$

Question 10

If you have $$5.00\ \mathrm{mol} of Mg$$, what is the total mass in grams? (Molar mass of Mg = $$24.31\ \mathrm{g/mol})$$

Accepted Answer

$$121.6\ \mathrm{g}$$

Question 11

A laboratory experiment requires $$0.500\ \mathrm{mol} of $$NaCl. What mass of NaCl should be weighed out? (Molar mass of NaCl = $$58.44\ \mathrm{g/mol})$$

Accepted Answer

$$29.2\ \mathrm{g}$$

Question 12

Which calculation correctly converts $$100.0\ \mathrm{g} of Mg to $$moles? (Molar mass of Mg = $$24.31\ \mathrm{g/mol})$$

Accepted Answer

$$\frac{100.0\ \mathrm{g}}{24.31\ \mathrm{g/mol}}$$

Question 13

A nutrition label states that a serving contains $$0.250\ \mathrm{mol} of $$NaCl. What is the mass of NaCl in this serving? (Molar mass of NaCl = $$58.44\ \mathrm{g/mol})$$

Accepted Answer

$$14.6\ \mathrm{g}$$

Question 14

Which of the following is the correct setup to convert $$75.0\ \mathrm{g} of Ag to $$moles? (Molar mass of Ag = $$107.87\ \mathrm{g/mol})$$

Accepted Answer

$$75.0\ \mathrm{g} 	imes \frac{1\ \mathrm{mol}}{107.87\ \mathrm{g}}$$

Question 15

A chemical reaction requires $$3.00\ \mathrm{mol} of $$NaCl. What is the mass in grams needed? (Molar mass of NaCl = $$58.44\ \mathrm{g/mol})$$

Accepted Answer

$$175.3\ \mathrm{g}$$

Question 16

If a sample contains $$0.250\ \mathrm{mol} of Mg$$, what is its mass in grams? (Molar mass of Mg = $$24.31\ \mathrm{g/mol})$$

Accepted Answer

$$6.08\ \mathrm{g}$$

Calculations Involving Molar Mass: Converting Between Mass and Moles

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