Solutions and mixtures Flashcards
Why do some people use filters for tap water?
Tap water has been filtered and treated to make it safe for drinking but it does not only contain water.It is still a mixture,with many other substances dissolved in the water.
Some substances dissolve in a liquid to make a solution.In a solution,the dissolved substance breaks up into pieces so small that light passes through the mixture.Because of this,solutions are transparent.A solution may be coloured or colourless,depending on the substance in it.
write the names of two solids and one gas that dissolves in water?
solid: sugar and salt
gas: carbon dioxide
suggest two ways you could tell that a liquid was a solution?
It is stable and doesn’t change over time or settle.
The solute particles are so small they cannot be separated by filtering.
What kinds of mixtures are there?
water that carries waste materials need to be treated in a water treatment plant so that it does not harm people or the environment.Waste water is not a single substance -it is not a pure substance.it is a mixture of water and solid substances.
Mixtures are grouped depending on whether the substances in them are solids,liquids or gases,and on how the substances can be separated.
-A solution is a mixture in which the solid dissolves in the liquid.This makes the mixture clear or transparent.
-A suspension is a mixture of two substances that separate if the mixture is not stirred.These two substances are often a solid and a liquid.When they are mixed,we say that one substance is suspended in the other.An example is sand mixed with water.
-In a colloid, one substance is dispersed in another substance and the two substances will not separate easily.Either substance may be solid,liquid or gas.A colloid is cloudy or opaque,so it is easy to see that it is a mixture.Milk is a colloid of different milk solids dispersed in water.
Many mixtures we use are colloids, such as hair spray,hand cream,styrofoam cups,paint and gel inks.Different kinds of colloid have properties that make them useful in different ways.
Give an example of solid liquid and gas?
Solid:Ice
Liquid:Water
Gas:Carbon Dioxide
A sample of water is collected from a stream suggest how you could separate out of the following
a) Sand
A mixture of sand and water can be separated by the process ofsedimentation
a) Dissolving is a reversible change what does the mean a) Give one example of reversible change
a) A reversible change isa change that can be undone or reversed.
b) example water if we freeze the water it turns into ice then if you keep it out for few minutes it will turn back into water you can reuse it again and again
name seven separation techniques
filtration,evaporation,distillation,magnetic separation,sieving,chromatography and separation funnel
