Solubility Flashcards
What is diffusion?
When particles move randomly from where they are in high concentration to where they are in low concentration.
What are ionic and covalent compounds solubility in water like?
Most ionic compounds e.g sodium chloride, are soluble in water
Most covalent compounds are insoluble in water, e.g silicon dioxide.
Define solubility?
Solubility is defined as the mass of solute required to saturate 100g of water at a particular temperature
What are Factors that affect solubility?
- Volume of water
- stirring the mixture
- Temperature
- surface area
What are solubility graphs?
We call the lines of the graph solubility curves. They show us how much salt dissolves at different temperatures.
Look in book for example
What is a saturated solution?
A saturated solution is one in which no more solute will dissolve at that temperature.
What happens to the solubility of gases and solids as the temperature increases?
The solubility of solids increases as temperature increases unlike gases which get less soluble as temperature increases.
Why do gases solubility decrease as the temperature rises in water?
As the temperature rises, the gas particles dissolved in the water gain energy and become less dense. They therefore rise and escape from the surface of the water.
What is a precipitate?
A precipitate is a solid which may be formed on mixing two solutions.
How does thermal pollution affect aquatic life?
Aquatic life depends on the amount of oxygen dissolved in water.
Some power stations use water as a coolant and may return warm water into the rivers.
Therefore, thermal pollution will raise the temperature of sea water which will result in less oxygen dissolving.
This will mean that there is less oxygen available for respiration and so results in the death of aquatic life.
What are the apparatus and chemicals for investigating the solubility of a salt?
Apparatus - Boiling tube Chemicals - Potassium Chlorate
Measuring cylinder Distilled Water
Thermometer
Stand and clamp
What is the method for investigating the solubility of a salt?
- Weigh 2g of potassium chlorate and place in a boiling tube.
- Measure 4cm3 of distilled water using a pipette and add to the boiling tube.
- Heat the boiling tube in a water bath and stir GENTLY until the potassium chlorate is just dissolved.
- Stirring, allow the solution to cool and record the temperature at which the crystals first appear in the table.
- Add a further 4 cm3 of distilled water to the boiling tube and repeat steps 3 and 4.
- Repeat steps 3 and 4, each time adding 4cm3 of distilled water until the total volume of water is 20cm3.
- Complete the results table and draw a solubility curve with temperature on x-axis and solubility of potassium chlorate on the y-axis.
How do you calculate the solubility of a salt in water?
1cm3 of water = 1g of water
Solubility = mass of salt / mass of water added x 100
e.g if 2g of potassium chlorate dissolve in 4cm3 of water then the solubility per 100g of water is:
2/4 x 100 = 50g potassium chlorate/100g water
