Molarity

2.3 moles of NaCl are dissolved to make 0.45 L of solution. What is the molarity?

• 1.41 M

• 5.11 M

• 2.3 M

• 0.011 M

2 moles of CaCO₃ are dissolved to make 1.22 L of solution. What is the molarity?

• 1.64 M

• 0.65 M

• 2.44 M

• 3.68 M

How many moles of Na₂SO₄ were dissolved to make 12 mL of a 0.45M solution?

• 0.0054 moles

• 2 moles

• 0.5 moles

• 1 mole

Answer explanation

1) convert mL to L

2) n = M*V

How many moles of LiF were dissolved in 65 mL of water to make a 1.25 M solution?

• 0.8125 moles

• 8.125 moles

• 0.08125 moles

• 81.25 moles

Answer explanation

1) convert mL to L ( 1000 mL = 1 L)

2) n = M*V

0.8 moles of MgSO₄ is dissolved to make 5 L of solution. What is the molarity?

• 0.8 M

• 0.16 M

• 0.32 M

• 4 M

How many milliliters of water are required to dissolve 28 grams of CaO to form a 1.15M solution?

• 322 mL

• 24.35 mL

• 0.45 mL

• 435 mL

Answer explanation

1) convert grams to moles (n) by dividing by molar mass

2) volume in liters = n/M

3) convert to mL (1 L = 1000 mL)

How many liters of water are required to dissolve 98 grams of NaOH to form a 0.75M solution?

• 3.27 L

• 4.25 L

• 2.13 L

• 1.98 L

Answer explanation

1) convert grams to moles (n) by dividing by molar mass

2) volume in liters = n/M

A solution contains 96 grams of methanol (CH₃OH) in 2 liters of solution. What is the molarity of this solution?

• 0.5 M

• 2.0 M

• 1.5 M

• 3.0 M

Answer explanation

1) divide grams by molar mass to get moles

2) M = n/V

How many grams of potassium nitrate (KNO₃) would you add to 150 mL of water to prepare a 0.2M solution?

• 0.03 g

• 3.03 g

• 30 g

• 303 g

Answer explanation

1) convert mL to L

2) calculate number of moles using n = M*V

3) multiply by molar mass to get grams

How many grams of sodium hydroxide (NaOH) do I need to make a 1.0M solution if I have 1.00 L of water?

• 40 grams

• 1 gram

• 10 grams

• 20 grams

Answer explanation

1) find # moles using: n = M*V

2) multiply by molar mass to get grams