# Worksheet: Molar Concentrations

In this worksheet, we will practice calculating the molar concentration of a solution from the solvent volume and mass or moles of the dissolved solute.

Q1:

Calculate the volume in L of a 0.125 M boric acid solution containing 0.500 mol of boric acid.

Q2:

A 600 mL solution contains 10.1 g of magnesium chloride. What is the molar concentration of magnesium chloride in this solution?

Q3:

1.0 liter of a sodium chloride solution contains 2.0 moles of sodium chloride. What is the concentration of sodium chloride?

Q4:

A 0.80-liter solution contains 0.40 moles of acetic acid. What is the molar concentration of acetic acid in this solution?

Q5:

Distilled white vinegar is a solution of acetic acid, , in water. A 0.500 L vinegar solution contains 25.2 g of acetic acid. What is the concentration of the acetic acid solution in units of molarity?

• A0.210 M
• B0.621 M
• C1.19 M
• D0.839 M
• E0.938 M

Q6:

Which of the following values is not equivalent to 1 dm3?

• A1,000 mm
• B1,000 L
• C1,000 cm3
• D1 L

Q7:

Which of the following statements best describes the concentration of a solution?

• AHow reactive a solute is with water
• BThe amount of solvent dissolved in a certain volume of solute
• CThe amount of solute dissolved in a certain volume of solution
• DHow quickly a solute dissolves in a solvent
• EThe smallest amount of water needed to dissolve a solute

Q8:

A student dissolves 25 g of in 500 cm3 of water. What is the concentration of the solution in moles per cubic decimeter? Give your answer to 2 decimal places.

Q9:

A 500 mg tablet of paracetamol was dissolved in 200 mL of water. What is the concentration of the resulting solution? Give your answer in units of mol/dm3 and to 2 significant figures.

Q10:

A 1 M solution of is prepared by dissolving 159.5 g of in 1 liter of water.

What would happen to the concentration if the amount of water was doubled?

• AThe concentration would stay the same.
• BThe concentration would double.
• CThe concentration would halve.

What would happen to the concentration if the amount of used to prepare the solution was doubled?

• AThe concentration would stay the same.
• BThe concentration would halve.
• CThe concentration would double.

Q11:

A solution was prepared by dissolving a certain amount of in 250 cm3 of water. If the concentration of the resulting solution was 0.5 mol/dm3, how much was dissolved? Give your answer to 1 decimal place.

Q12:

Gallium chloride is formed from excess gallium using 2.60 L of 1.44 M hydrochloric acid.

Calculate the number of moles of gallium reacted.

Calculate the mass of gallium chloride formed.

Q13:

Blood sugar concentration measures the number of milligrams of glucose present in 100 mL of blood and is a useful tool for diagnosing diabetes. The blood sugar level for an average adult should contain less than 125 mg of glucose. What concentration is this? Give your answer to 3 significant figures and in units of millimoles per liter.

Q14:

Which of the following is the formula for calculating the concentration of a solution?

• AConcentration = number of moles of solute × total volume of solution
• BConcentration = total volume of solution + number of moles of solute
• CConcentration = number of moles of solute/total volume of solution
• DConcentration = number of moles of solute − total volume of solution
• EConcentration = total volume of solution/number of moles of solute

Q15:

A student wants to prepare a 0.1 M solution of silver nitrate in a volumetric flask that can contain 100 mL of water. How much silver nitrate does the student need to dissolve? Give your answer to 2 significant figures.

Q16:

A student prepares three different solutions of zinc sulfate, as shown in the diagram. Which solution has the highest concentration? • ASolution A
• BSolution B
• CSolution C