Transcript Dissolving Race

Solutions
Dissolving race (animation may
not work on all computers)
Solutions
A solution is a mixture...usually a mixture of
a solid and a liquid e.g. salt and water
But it can be 2 liquids like milk and tea = solution
Or a gas and a solid like
air and sugar(marshmallow)= solution
• Some chemicals seem to disappear when
they are stirred with water.
• Example: When sugar is put into water or
tea it seems to disappear.
• When this happens, we say the substance
has dissolved.
Solubility?
• A substance which dissolves is called a
soluble substance.
• Eg. Salt and water
• A substance that does not dissolve is
called an insoluble substance.
• Eg. Oil or sand and water
Dilute vs. Concentrated
• If there is lots of solute in the solvent then
it is concentrated e.g. strong mi-wadi
• If there is very little solute compared to
the solvent then it is dilute e.g. very
weak mi-wadi
• When any substance dissolves, we say
that a solution has been made.
• the substance that has dissolved is given a
special name. It is called the solute.
• Salt and water: Which one is the solute?
• Which one is the solvent? _____
• The substance (usually liquid) that the
solute dissolves in is called the SOLVENT
Solute, Solvent and Solution
What if the solid doesn’t dissolve?
It’s insoluble
• Insoluble substances form a suspension
with water. A suspension is cloudy.
• So the solid will fall to the bottom after a
few minutes!!
Solvent
• It is not just water that dissolves things,
any liquid which dissolves things is called
a solvent.
• Water is a solvent, so is petrol and nail
varnish remover.
• You will meet many more solvents
throughout your life.
• Eg.__________________
Re-cap
• A solution is a mixture of a soluble
substance (solute) and a solvent.
• A solute is _________________________
• A solvent is________________________
Is there a limit to how much solid can dissolve?
We know we can add a
spoon of sugar to a cup of
hot tea and it will dissolve.
What would happen if the tea
were cold?
If we carry on adding sugar, there will come a
point when the sugar will not dissolve in the
tea, because there isn’t any more room for the
sugar molecules.
If we were to put salt into the
same volume of tea the
maximum number of tea spoons
that could dissolve in the tea
would be different.
What would happen if the liquid was NOT tea?
• A saturated solution is one in which no more
substance will dissolve in the liquid.
• A saturated solution contains as
much dissolved solute as possible at that
temperature