Calculations In Aqueous Solution

Question 1

What is concentration?

Answer 1

Concentration is a measure of the amount of solute dissolved per unit of solvent.

Concentration can be quantified using the equation: c = n/V, where n is the amount in moles and V is the volume in dm³.

Question 2

What is the equation for calculating concentration?

Answer 2

c = n/V

In this equation, c is the concentration in moldm³, n is the amount of solute in moles, and V is the volume of solvent in dm³.

Question 3

What is molarity?

Answer 3

Molarity is another term for concentration, expressed in moldm⁻³.

It quantifies the number of moles of solute per liter of solution.

Question 4

How do you calculate the concentration of a solution formed from 0.20 mol of NaCl in 400 cm³ of water?

Answer 4

c = 0.20/(400/1000) = 0.50 mol dm⁻³

Remember to convert cm³ to dm³ by dividing by 1000.

Question 5

What is the concentration of a solution formed when 16.0 g of NaOH is dissolved in 200 cm³ of water?

Answer 5

c = 0.40/(200/1000) = 2.0 mol dm⁻³

The amount of NaOH is calculated using amount = mass/molar mass.

Question 6

What is the formula for calculating percentage yield?

Answer 6

Percentage yield = (actual amount of product / theoretical amount of product) × 100

This calculation can help determine the efficiency of a chemical reaction.

Question 7

How do you find the theoretical yield of ammonium nitrate from 100 cm³ of 0.25 moldm⁻ nitric acid?

Answer 7

Theoretical yield = 0.025 mol of ammonium nitrate

This is calculated from the amount of nitric acid used: c × V = 0.25 × (100/1000).

Question 8

How is the actual amount of ammonium nitrate calculated if 1.6 g is produced?

Answer 8

Actual amount = 1.6/80 = 0.020 mol

The molar mass of ammonium nitrate is 80 g/mol.

Question 9

What is the percentage yield if the actual yield of ammonium nitrate is 0.020 mol and the theoretical yield is 0.025 mol?

Answer 9

Percentage yield = (0.020/0.025) × 100 = 80%

This indicates the efficiency of the reaction.

Question 10

Fill in the blank: The equation for calculating the concentration of a solution is ______.

Answer 10

c = n/V

Question 11

True or False: A solution becomes more concentrated as more solute is added.

Answer 11

True

Question 12

What is the molarity of a solution formed when 0.40 mol of NaOH is dissolved in 200 cm³ of water?

Answer 12

2.0 mol dm⁻³

This is calculated by converting volume from cm³ to dm³.

Question 13

What is the relationship between volume in cm³ and dm³?

Answer 13

1000 cm³ = 1 dm³

Question 14

What is the amount of nitric acid used if 100 cm³ of 0.25 moldm⁻ is used?

Answer 14

0.025 mol

This is calculated using c × V.

Question 15

Fill in the blank: The actual amount of ammonium nitrate produced from 1.6 g is ______.

Answer 15

0.020 mol