Molarity and Mass Percent

What is the percent by mass of a solution made by dissolving 20.0 g of NaCl into 180.0 g of water?

• 10.0 %

• 11.1 %

• 80.0 %

• 20.0 %

Answer explanation

20g / (180g+ 20g) x 100 = 10 %

What is the percent by mass of a solution made by dissolving 10.0 g of NaCl into 180.0 g of water?

• 5.26 %

• 5.56 %

• 180.0 %

• 20.0 %

Answer explanation

10 g / (10 g + 180 g) x 100 = 5.26 %

What is the percent by mass of a solution containing 56.5 g of salt in 500 g of water?

• 11.3 %

• 5.56%

• 8.85%

• 10.2 %

Answer explanation

56.5g / ( 56.5g + 500g) x 100 = 10.2 %

What is the molarity of a 0.5L sample of a solution that contains 60.0 g of sodium hydroxide (NaOH)

• 0.8 M

• 1.5M

• 3.0M

• 6.0M

What is the molarity of a solution that contains 5 moles of solute in 2 liters of solution?

• 2.5 M

• 5 M

• 10 M

• 0.4 M

What is the definition of molarity?

• The mass of a substance in grams

• The number of particles in a substance

• The number of moles of solute per liter of solution

• The volume of solvent in liters

Tags

NGSS.HS-PS1-5

Which of the following is the correct formula for calculating molarity?

• moles/liters of solution

• moles/kg of solvent

• # particles/Avogadro's #

• theoretical yield/actual yield

If you have 0.045 L of 0.465 M potassium bromide. How many moles of potassium bromide are present?

• 20.9 mol

• 0.021 mol

• 0.02 mol

• 0.0209 mol

What is the molarity of 4 g of NaCl (molar mass =58.45) in 3,800 mL of solution?

• 0.018 M

• 0.0011 M

• 1.052 M

• 0.062 M

Find the molarity of 186.55 g of sucrose, C₁₂H₂₂O₁₁ (molar mass = 342 ) in 250 mL of water.

• 2.18 M

• 0.746 M

• 1.18 M

• 0.545 M