Topic 2: States of Matter and Mixtures Flashcards
What is the particle arrangement of a solid?
Regular
What is the particle movement of a solid?
The particles vibrate around a position
What is the relative energy of particles of a solid?
Low
What is the particle arrangement of a liquid?
Random
What is the particle movement of a liquid?
Move around each other
What is the relative energy of particles of a liquid?
Medium
What is the particle arrangement of a gas?
Random
What is the particle movement of a gas?
Move quickly in all directions
What is the relative energy of particles of a gas?
High
Are changes between states chemical or physical changes?
Physical changes
What is the change of state called when a solid turns into a liquid?
Melting
What is the change of state called when a liquid turns into a gas?
Boiling
What is the change of state called when a gas turns into a liquid?
Condensing
What is the change of state called when a liquid turns into a solid?
Freezing
What can melting and boiling point data can be used to predict?
A substances state at a given temperature
What happens during melting and boiling?
- Substances heat up
- Particles gain energy
- Forces between particles weaken
- Particles break free from position changing its state
What happens during condensing and freezing?
- Substances cools down
- Particles lose energy
- Forces between particles strengthen
- Particles are held in position changing its state
When do chemical changes happen?
In chemical reactions
What is the everyday definition of a pure substance?
Clean or natural
What is the chemical definition of a pure substance?
A substance containing only one element or compound
What are properties of a chemically pure substance?
It’ll have a sharp melting point
It’ll have a sharp boiling point
What is the equipment used to find the melting point of a substance?
Melting point apparatus
OR
With a water bath and thermometer
What is a mixture?
A substance made up of different elements or compounds that aren’t chemically bonded to each other
What is an example of a mixture?
Air
What is an impure substance an example of? What does this mean?
It’s an example of a mixture of - so will melt over a range of temperatures
What is filtration?
The separation of insoluble solids from liquids or solutions
What can filtration be used for?
Can be used to separate out a solid product or purified a liquid by removing insoluble impurities
What is the process of filtration?
- Take a filter paper and a funnel
- Put the filter paper in the funnel and pour the solution into the funnel over a beaker
- The solid is left in the filter paper and the liquid will go to the beaker
What is evaporation?
The separation of soluble salts from solution
What is the process of evaporation?
- Put the solution on an evaporating dish
- Put the dish over a Bunsen burner and slowly heat the solution
- Crystals will form and dry or as the solvent evaporates
What is crystallisation?
A process that separates soluble salts from solution
What is the process of crystallisation?
- Heat solution but cool it when crystals start to form
- Large crystals from as solution cools
- Filter out crystals leave to dry
What are the 2 types of distillation?
- Simple distillation
- Fractional distillation
What is the process of simple distillation?
- Heat a solution using a Bunsen burner
- Water vapour will produce first because it’s the part of the solution with the lowest boiling point
- Will be cooled and condensed by cold water that goes in and out of a condenser
- Pure water would be produced
What is the process of fractional distillation?
- A mixture of liquids are heated
- The fractionating column (which is filled with glass rods) allows liquids to evaporate at different times
- The liquids reach the top of the column when the temperature at the top matches their boiling point
- The condenser then condenses the different fractions at each of their different boiling points
- Fractions are collected separately
What is the main difference between what simple distillation and fractional distillation can do?
Simple distillation can’t separate liquids with similar boiling points BUT fractional distillation can
What is chromatography?
A method used to separate a mixture of soluble substances
What is the process of chromatography?
- Use filter paper with a spot of mixture on it (e.g. ink) that lies in a pencil line
- Place the filter paper inside a watch glass that has the solvent in it, the pencil line CANNOT touch the solvent
- The solvent will then rise in the filter paper
- Remove the filter paper when solvent is nearly at the top of it
- This will then produce a chromatogram
- Locating agents can be sprayed on the chromatogram to show spots of colourless chemicals
What are the 2 phases of chromatography?
- Stationary phase
- Mobile phase
What is the stationary phase of chromatography?
Where the molecules can’t move e.g. chromatography paper
What is the mobile phase of chromatography?
Where the molecules can move (the solvent) e.g. water or ethanol
What is a Rf value?
The ratio between the distance travelled by the solute and the distance travelled by the solvent
How is Rf calculated?
Rf = distance travelled by solute (B)/distance travelled by solvent (A)
What is the distance travelled by the solute (B)?
The distance between the baseline (origin) and the spot of chemical
What is the distance travelled by the solvent (A)?
The distance between the baseline (origin) and the solvent front
What type of tests can chromatography be used for?
Purity tests
Why don’t pure substances separate in chromatography?
They move as one spot
How can a substance be identified using the Rf value?
- Run it alongside a pure sample of a known substance
- If they have the same Rf value, they’re likely the same substance
What is potable water?
Water that is safe to drink
Why is potable water not chemically pure?
It can contain low levels of dissolved salts and microbes
What is the source of ground water?
Underground rocks
What is the source of salt water?
Sea water
What is the source of waste water?
Water contaminated by a human process e.g. as a by product in industry
How are waste water and ground water made potable?
The process of treating (mesh, filtration, sedimentation, chlorination)
How can the process of how water is treated be remembered?
My
Fathers
Sweet
Curry
What is the process of treating water? What does each stage do?
- Put water through mesh - removes any large debris such as twigs
- Sedimentation - iron sulfate or aluminium sulfate added to water, making fine particles clump together and settle at the bottom
- Sand and gravel filtration - removes any smaller solid bits
- Chlorination - chlorine gas bubbled through to kill harmful bacteria and other microbes
How is sea water made potable?
Distillation
What is distillation of sea water?
Boiling the sea water to separate it from dissolved salts - requires a lot of energy
How should water be prepared to be used for chemical analysis? Why?
Should be deionised - as tap water has ions in it that can interfere with reactions
COMPOSITION OF INK CORE PRACTICAL: What are the 2 techniques used to investigate the composition of inks?
- Simple distillation
- Paper chromatography
COMPOSITION OF INK CORE PRACTICAL: What does simple distillation show when investigating composition of inks?
Separate solvent from dyes if solvent has lowest boiling point
COMPOSITION OF INK CORE PRACTICAL: What is the process of simple distillation done to investigate the composition of inks?
- Put the ink into a conical flask and heat it using a Bunsen burner
- The ink will then evaporate
- Using the thermometer that connected to the flask, check the temperature that the solvent is collected and condensed to find its boiling point - condense the gas using a condenser (that has cold water running through it)
- Collect the solvent produced in a beaker
COMPOSITION OF INK CORE PRACTICAL: What can the boiling point of the solvent produced in fractional distillation (used to investigate the composition of inks) show?
It can help identify the solvent produced
COMPOSITION OF INK CORE PRACTICAL: What does paper chromatography show when investigating composition of inks?
It can separate out the different dyes
COMPOSITION OF INK CORE PRACTICAL: What is the process of paper chromatography done to investigate the composition of inks?
- Use filter paper with a spot of ink on it that lies on the a pencil line which is next to a spot of pure dye also on the line
- Place the filter paper inside a watch glass that has the shallow solvent in it, the pencil line CANNOT touch the solvent
- The solvent will then rise in the filter paper and separate the dyes
- Remove the filter paper when solvent is at the top of it
- This will then produce a chromatogram
- If a spot from the ink matches that of the pure dye, that dye may be present in the ink
COMPOSITION OF INK CORE PRACTICAL: How can dyes be identified in paper chromatography?
Comparing their Rf values to known compounds
What are the 3 methods to remove soluble products from a solution?
- Chromatography
- Evaporation
- Crystallisation