topic 2 - states of matter and mixtures

describe the arrangement of particles in solid matter

• tightly packed

• regular pattern

describe the movement of particles in solid matter

vibrate around a fixed position

describe the relative energy of particles in solid matter

low energy

describe the density of particles in solid matter

high density

describe the arrangement of particles in liquid matter

• randomly arranged

• but all particles are touching

describe the movement of particles in liquid matter

move around each other

describe the relative energy of particles in liquid matter

greater energy than solid particles

describe the density of particles in liquid matter

medium density

describe the arrangement of particles in gas matter

randomly arranged

describe the movement of particles in gas matter

• move at a range of speeds

• in all directions

describe the energy of particles in gas matter

high energy

describe the density of particles in gas matter

low density

recall the name of the interconversion from solid to liquid

melting

state the physical changes that occur in melting

matter goes from solid to liquid

state the chemical changes that occur in melting

• due to temperature increase, particles in solid matter gain kinetic energy

• causing the particles to start to move around each other

recall the name of the interconversion from liquid and gas matters

boiling

state the physical changes that occur in boiling

matter changes from liquid to gas state

state the chemical changes that occur in boiling

• due to temperature increase, the particles in liquid matter gain kinetic energy and overcome bonds of attraction between particles

• causing the particles to move freely at a range of speeds in random directions

recall the name of the interconversion from gas to liquid matters

condensation

state the physical changes that occur in condensation

matter changes from a gas to a liquid state

state the chemical changes that occur in condensation

• due to temperature decrease, the gas particles lose kinetic energy

• causing the particles to slow and move around each other

recall the name of the interconversion from liquid to solid matter

freezing

state the physical changes that occur in freezing

matter changes from liquid to solid state

state the chemical changes that occur in freezing

• due to temperature decrease, the liquid particles lose kinetic energy

• causing the particles to slow and start vibrating around a fixed point

recall the name of the interconversion from solid to gas

sublimation

state the physical changes that occur in sublimation

matter changes from a solid to gas state

state the chemical changes that occur in sublimation

• due to temperature increase, the solid particles gain kinetic energy and overcoming bonds of attraction between particles

• causing the particles to move freely at a range of speeds in random directions

explain the difference between the use of ‘pure’ in chemistry and everyday use

• in everyday language, pure means when something is natural or clean

• in chemistry, pure means a substance that consists of a single element or compound

• which contains no other substances

state the definition of pure in chemistry

• pure means a substance that consists of a single element or compound

• which contains no other substances

state the differences in chemistry between a pure substance and a mixture

• a pure substance contains ONE element or compound CHEMICALLY BONDED together

• a mixture contains TWO OR MORE elements or compounds that are PHYSICALLY MIXED together

state how to interpret melting point data to recognise a pure substance

pure substances have sharp melting points

state how to interpret melting point data to recognise a mixture

mixtures have melting range of temperatures

explain the type of mixtures that can be separated by simple distillation

• separates a liquid from a soluble solid in a solution

• or a pure liquid from a mixture of liquids

state the method of simple distillation

1. heat the solution in a distilling flask, using a bunsen burner

2. as the pure liquid evaporates, the vapour is captured and passes through the liebig condenser

3. the vapour cools and condenses, turning into a pure liquid that is collected in a beaker

explain the types of mixtures that can be separated by fractional distillation

separates two or more liquids which are miscible

state the method of fractional distillation

1. set up the apparatus as pictured

2. heat the solution in a distilling flask, using an electric heater

3. the solution is heated to the temperature of the substance with the lowest boiling point

4. the substance with the lowest boiling point evaporates and its vapour is collected in the liebig condenser

5. as the vapour passes through the condenser, it cools and condenses to form a pure liquid

6. this liquid is collected in a beaker

7. repeat the experiment as many times as needed for different types of liquids by changing the temperature on the electric heater

explain the types of mixtures that can be separated by filtration

separates an insoluble solid from a liquid

state the method of filtration

1. place a filter paper in a funnel above a beaker

2. add the mixture of the insoluble solid and liquid to the filter funnel

3. the filter will only allow the small liquid particles through as a filtrate

4. solid particles are too large to pass through the filter paper so remain in the filter funnel as residue

explain the types of mixtures that can be separated by crystallisation

separates a soluble solid from a solution when the solid is more soluble in hot than cold solvents

state the method of crystallisation

1. heat the solution in an evaporating basin until the solvent has evaporated, leaving a saturated solution behind

2. cool the saturated solution slowly

3. as the solution cools, crystals will start to form

4. filter the solution to separate the crystals from the solvent

5. wash the crystals with distilled water to remove impurities

6. dry with a paper towel

explain the types of mixtures that can be separated by paper chromatography

separates substances with different solubilities within a solution

state the method of paper chromatography

1. draw a pencil line horizontally-across a piece of chromatography paper

2. place a small dot of each substance onto the pencil line equal distances apart

3. lower the paper into the solvent so that the pencil line sits above the level of the solvent

4. the solvent travels up the paper by capillary action

5. the substances with higher solubilities will travel further up the paper than substances with lower solubilities

describe what paper chromatography is

• separation of mixtures of soluble substances

• by running a solvent (mobile phase)

• through the mixture on the paper (paper is stationary phase)

• causing the substances to move at different rates over the paper

state how to interpret a paper chromatogram to distinguish between pure and impure substances

• pure substances will only produce one spot on the chromatography paper

• as the paper shows each different component of a mixture as a spot

• impure substances will produce more than one spot on the chromatography paper

state how to calculate Rf values

Rf = distance travelled by substance / distance travelled by solvent

explain how to investigate the composition of inks (method)

1. use simple distillation to separate the dyes and solvents in the ink

2. use a pencil to draw a horizontal line across a piece of chromatography paper

3. add a dot of each known solvent on the pencil line using a different capillary tubes

4. use another capillary tube to add a dot of the unknown solvent from the ink on the pencil line

5. lower the chromatography paper into the water until the pencil line is above the level of the solvent

6. allow the solvents to travel undisturbed up the chromatogram paper

7. measure the distance travelled by the water and measure the distance travelled by each solvent

8. calculate the Rf value of each solvent

9. compare the Rf value of the unknown solvent to the other solvents to discover what the unknown solvent is