1. What is the weight/volume percentage concentration of 250mL of aqueous sodium chloride solution containing 5g NaCl?

Calculate the weight/volume (%) = mass solute ÷ volume of solution x 100
mass solute (NaCl) = 5g
volume of solution = 250mL

w/v (%) = 5g ÷ 250mL x 100 = 2g/100mL (%)

2. 10.00g BaCl_{2} is dissolved in 90.00g of water. The density of the solution is 1.09g/mL. Calculate the weight/volume percentage concentration of the solution.

Calculate the volume of the solution: density = mass solution ÷ volume solution
mass solution = 10g BaCl_{2} + 90g water = 100.00g
volume solution = mass ÷ density = 100g ÷ 1.09g/mL = 91.74mL

Calculate w/v (%) = mass solute ÷ volume solution x 100
mass solute (BaCl_{2}) = 10.00g
volume solution = 91.74mL

1. 2.0L of an aqueous solution of potassium chloride contains 45.0g of KCl. What is the weight/volume percentage concentration of this solution in g/100mL?

Convert the units (mass in grams, volume in mL):
mass KCl = 45.0g
volume of solution = 2.0L = 2.0 x 10^{3}mL = 2000mL

Calculate w/v (%) = mass solute (g) ÷ volume solution (mL) x 100
w/v (%) = 45.0 ÷ 2000mL x 100 = 2.25g/100mL (%)

2. 15mL of an aqueous solution of sucrose contains 750mg sucrose. What is the weight/volume percentage concentration of this solution in g/100mL?

Convert the units (mass to grams, volume to mL)
mass solute (sucrose) = 750mg = 750 ÷ 1000 = 0.750g
volume solution = 15mL

3. 186.4L of aqueous sodium hydroxide solution contains 1.15kg NaOH. What is the weight/volume percentage concentration of this solution in g/100mL?

Convert the units (mass to grams, volume to mL)
mass solute (NaOH) = 1.15kg = 1.15 x 1000 = 1,150g
volume solution = 186.4L = 186.4 x 1000 = 186,400mL

calculate w/v (%) = mass solute (g) ÷ volume solution (mL) x 100
w/v (%) = 1,150g ÷ 186,400mL x 100 = 0.62g/100mL (%)

Reagent Volume-Mass Calculations

1. A student must add 1.22g of sodium chloride to a reaction vessel. The student is provided with an 11.78g/100mL (%) aqueous sodium chloride solution. What volume of this solution must be added to the reaction vessel?

Re-arrange the equation: w/v(%) = mass solute (g) ÷ volume solution (mL) x 100
volume solution (mL) = mass solute (g) ÷ w/v(%) x 100

Subsitutue in the values:
volume solution (mL) = 1.22g ÷ 11.78g/100mL x 100
volume solution = 10.36mL

2. What is the mass in grams of potassium iodide in 14.86mL of a 32.44g/100mL aqueous potassium iodide solution?

Re-arrange the equation: w/v(%) = mass solute (g) ÷ volume solution (mL) x 100
mass solute (g) = w/v (%)/100 x volume solution(mL)

Subsitutue in the values:
mass KI = 32.44/100 x 14.86 = 4.82g

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