Investigating Solubility

This practical lesson covers:

  1. The solubility of a solid in water at a specific temperature

Investigating the relationship between temperature and solubility


Aim

To investigate the solubility of a solid in water at a specific temperature. 

Background information

When a soluble substance is added to water it dissolves. A saturated solution is formed when no more solute can be dissolved in the water. The amount of solute that can be added to a solvent before it becomes saturated, varies with temperature. In this practical, you will investigate the solubility of powdered sodium chloride at different temperatures.

Equipment

  1. 250 cm3 beaker
  2. Thermometer
  3. Digital mass balance
  4. Glass rod
  5. Powdered sodium chloride

Method

  1. Pour 200 cm3 of deionised water into a 250 cm3 beaker. 
  2. Place beaker in a water bath at the desired temperature. 
  3. Add known masses of the powdered sodium chloride and mix with a glass rod. 
  4. Repeat step 3 until no more sodium chloride will dissolve. 
  5. Record the total mass added. 
  6. Repeat at 5 different temperatures. 

What is formed when a soluble substance is added to water and no more solute can be dissolved?

a dilute solution

a saturated solution

an unsaturated solution

a supersaturated solution

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How does the amount of solute that can be added to a solvent before it becomes saturated vary with temperature?

it varies randomly with temperature

it increases with increasing temperature

it decreases with increasing temperature

it remains constant

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What is the purpose of using a water bath in this experiment?

to increase the rate of dissolution

to maintain a constant temperature

to prevent the solution from becoming saturated

to allow the solute to dissolve completely

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What is the role of the glass rod in this experiment?

to determine the solubility of sodium chloride

to measure the temperature of the solution

to mix the solution

to weigh the powdered sodium chloride

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What is the dependent variable in this experiment?

the temperature of the water

the volume of water used

the mass of sodium chloride added

the type of solute used

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