Chemistry : States of Matter and Mixtures Flashcards
What do states of matter depend on?
The forces between particles
How many states of matter are?
Three: solid, liquid and gas
Are there strong or weak forces of attraction between particles?
Strong, this holds them in fixed positions in a regular lattice arrangement
Do the particles move position in a solid?
No, so all solids keeps a definite shape and volume
Do the particles in solids have much energy?
No
Do the particles in a solid vibrate more when the solid its heated?
Yes, it can cause the solid to expand when heated
Are there lots or only some forces of attraction between the particles in a liquid?
Only some, meaning the particles are free to move, but tend to stick together
Do liquids have a definite shape?
No, they will flow to fill the bottom of a container, however, they do keep the same volume
Do liquids have more energy in its particles than solids?
Yes, but less than in the gas state
Are the particles in solid constantly moving?
Yes, they are constantly moving with random motion
Do the particles in a liquid get faster while being heated?
Yes, the hotter the liquid gets, the faster they move, this causes the liquids to expand slightly when heated
Are there any forces of attraction between particles in gases?
No, the particles can move freely , they travel in straight lines and only interact when they collide
Do gases keep a definite shape or volume?
No, this means they will always fill any container
What happens when the particles of a gas bounce of the wall of a container?
They exert a pressure on the walls
Do particles in a gas state have more energy than in the solid or liquid state?
Yes
Are the particles in a gas constantly moving?
Yes, they are constantly moving with random motion
Do the particles get faster as the gas is heated?
Yes, the hotter it gets, the faster the particles move
The gas will either expand or their pressure will increase
Can heating or cooling a substance change its state?
Yes
What is it called when a solid is heated into a liquid?
Melting
What is it called when a liquid is cooled to a solid?
Freezing
What is it called when a liquid is heated to a gas?
Evaporating
What is it called when a gas is cooled to a liquid?
Condensing
What is it called when a solid is heated to a gas?
Subliming
What is it called when a gas is cooled to a solid?
Deposition
Are atoms rearranged during chemical reactions?
Yes, this causes chemical changes
What are chemical changes?
Chemical changes happen during chemical reaction, when bonds between atoms break and the atoms change places
The atoms from substances you start off with (the reactants) are rearranged to form different substances (the products)
Are chemical changes hard to reverse?
Yes
How many elements / compounds do pure substances contain?
One
What is substance that contains more than one compound called?
A mixture
How can the purity of a substance be tested?
Using melting points, this can be done by heating the substance; a pure substance should have on continuous melting point, so should all be melted/boiled off at the same point
What is simple distillation used for?
It is used for separating out a liquid from a solution
What is fractional distillation used for?
It is used for separating a mixture of liquids
What is filtration used to do?
To separate insoluble solid from a liquid
What can filtration also be used for?
It can also be used for purification
What does crystallisation do?
It separates a soluble solid from a solution
How many phases are involved in chromatography?
There are two phases
What is chromatography used for?
It is used for separating a mixture of soluble substances and identifying them
What is the first phase of chromatography called, and what is it?
It is called the mobile phase, and this is where the molecules can move; this always a liquid and a gas
What is the second phase of chromatography called, and what is it?
It is called the stationary phase, and this is where the molecules can’t move; this can be a solid or a really thick liquid
In paper chromatography, what is the mobile phase?
A solvent
In paper chromatography, what is the stationary phase?
A piece of filter paper
How do you work out the Rf value?
It is:
distance travelled by solute/
distance travelled by solvent
What is the baseline in chromatography written with?
Pencil, as it won’t move with the solvent
What are the three main sources of water the UK uses?
Surface water (from lakes, rivers and reservoirs)
Ground water (from aquifers -rocks that trap water underground)
Waste water (from water has been contaminated by human process, e.g. defecation)
What are the three steps in water purification?
Filtration - a wire mesh screens out large twigs, and then gravel and sand beds filter out any other solid bits
Sedimentation - iron sulphate and aluminium sulphate is added to the water, which makes fine particles clump together and settle at the bottom
Chlorination - chlorine gas is bubbled through to kill harmful bacteria and other microbes
Can you get potable water by distilling sea water?
Yes, however it is expensive
Does water used in chemical analysis need to be pure?
Yes, as any water other than deionised water may interfere with the reactions
