Topic 2 - States of Matter and Mixtures

Which state of matter has the strongest forces of attraction between particles?

Solid.

Which state of matter has the weakest forces of attraction between particles?

Gas.

Which state of matter has the highest density?

Solid.

Which state of matter has the lowest density?

Gas.

Describe the arrangement of solid particles.

Regular, very close, fixed positions and lattice structure.

Describe the arrangement of liquid particles.

Irregular, random and quite close.

Describe the arrangement of gas particles.

Irregular, random and far apart.

Describe the movement of solid particles.

Vibrate in fixed positions.

Describe the movement of liquid particles.

Slide and move around each other.

Describe the movement of gas particles.

Move randomly in all directions.

Compare the relative energies of particles in solids, liquids and gases.

Particles in a solid have the least amount of energy and particles in a gas have the most energy.

Can solids be compressed?

No.

Explain why solids cannot be compressed.

The particles are already close together her in a fixed lattice and cannot be pushed closer together.

Can liquids be compressed?

No.

Explain why liquids cannot be compressed.

Particles are already close together so cannot be pushed any closer.

Can gases be compressed?

Yes.

Explain why gases can be compressed.

Particles are far apart so can be pushed closer together.

Can solids take the shape of the container?

No.

Can liquids take the shape of the container?

Yes.

Can gases take the shape of the container?

Yes.

Compare the amount of energy of particles in solids and gases.

Solids have the least amount of energy whereas gases have the most amount of energy.

Describe the difference in movement between particles when they are in a liquid state is compared to a solid state.

In a liquid state, particles are constantly moving but in solid particles they vibrate in fixed positions.

Describe the difference in arrangement between particles when they are in a liquid state is compared to a solid state.

In a solid state, they are regularly arranged, very close together, fixed positions and lattice structure. In a liquid state, they are randomly arranged and further apart.

Describe the forces between particles in solids.

Strong forces of attraction between particles.

What does interconversion of state mean?

When matter changes from one state to another due to changes in temperature or pressure.

What type of energy allows particles to move?

Kinetic energy.

Are changes of state physical or chemical changes?

Physical.

Explain why changes of state are called physical changes rather than chemical changes.

• Physical changes do not result in the formation of a new substance and are easily reversible.

• The forces between particles are changed rather than the chemical properties of the substance.

Are chemical or physical changes easier to reverse?

Physical.

What is melting?

Solid to Liquid.

What is evaporation/boiling?

Liquid to Gas.

What is freezing?

Liquid to Solid.

What is condensation?

Gas to Liquid.

What is deposition?

Gas to Solid.

What is sublimation?

Solid to Gas.

What is it called when a solid becomes a gas?

Sublimation.

What is it called when a gas becomes a solid?

Deposition.

What is it called when a liquid becomes a solid?

Freezing.

What is it called when a solid becomes a liquid?

Melting.

What is it called when a liquid becomes a gas?

Evaporation.

What is it called when a gas becomes a liquid?

Condensation.

If a substance is below its melting point, what state of matter is it?

Solid.

If a substance is above its melting point and below its boiling point, what state of matter is it?

Liquid.

If a substance is above its boiling point, what state of matter is it?

Gas.

The ___ and ___ points of a substance are the same.

Melting and freezing point.

Are the melting and freezing point of a substance the same or different?

Same.

What happens to the forces of attraction when a solid turns into a liquid?

Overcome or broken.

State what is meant by the term melting point.

The temperature at which a solid turns into a liquid.

State what is meant by the term boiling point.

The temperature at which a liquid turns into a gas.

Describe what happens when a solid is heated and melts into a liquid.

• When heated the particles absorb thermal energy which is converted into kinetic energy.

• The particles in the solid vibrate more, causing the solid to expand until the structure breaks and becomes a liquid.

State the time at which the gas first started to form a liquid.

B.

Calculate the number of minutes it took from the gas starting to form a liquid until the substance was completely liquid.

6 - 2 =4 minutes.

What is a cooling curve?

A graph that shows how a substance changes from a gas to a liquid to a solid as temperature decreases.

How does a horizontal line on a cooling curve indicate?

Where a substance is changing state.

What is a mixture?

Contains 2 or more elements/compounds that are not chemically bonded.

Explain the graph.

• A to B: Particles in a solid are in fixed positions but begin to vibrate more rapidly as temperature increases.

• B to C: Particles in a solid use energy to break out of lattice/break bonds between particles. Particles becoming randomly arranged as it turns from a solid to liquid.

• C to D: Particles in liquid move past one another in a random arrangement. Particles move more rapidly as temperature increases in all directions.

Pick A, B, C or D.

C.

What is a pure substance?

Contains a single element or compound and has a fixed position.

Describe the melting and boiling points of a pure substance.

Melt and boil at specific temperatures.

How can you use melting point data to distinguish between pure substances and mixtures?

Pure substances have a specific, exact melting point whereas mixtures melt over a range of temperatures.

What property can be used to distinguish a pure substance from a mixture?

Melting and boiling point.

State the use of melting point analysis.

To assess the purity of a substance.

Does a pure substance or a mixture melt and boil over a range over temperatures?

Mixture.

Does a pure substance or a mixture melt and boil at a specific, sharp temperature?

Pure substance.

What is the difference between a pure substance and mixture?

A pure substance consists of only substance (this can be an element or a compound), while a mixture contains two or more different substances that are not chemically combined.

Salt is dissolved in water. Is this a pure substance or a mixture?

Mixture.

How can melting and boiling points distinguish between pure substances and mixtures?

Pure substances have specific and sharp melting and boiling points, while mixtures have a range of melting and boiling points.

Is substance A pure or impure?

Impure.

What is the purpose of filtration?

A separation technique used to separate mixtures of insoluble/undissolved solids from a solution.

Which separation technique can be used to separate mixtures of insoluble/undissolved solids from a solution?

Filtration.

What sort of mixtures can filtration be used to separate?

Insoluble/undissolved solids from a solution.

Which separation technique can be used to separate sand from a mixture of sand and water?

Filtration.

Explain the process of filtration.

• Filter paper placed in a filter funnel above a beaker.

• Mixture of insoluble solids and liquid poured into a funnel.

• Filter paper only allows small liquids (solution) to pass through. These liquids become known as the filtrate and collect in the conical flask.

• Insoluble solid particles are too large to pass through the filter paper so stay there. These solids become known as the residue.

What is the purpose of crystallisation?

A separation technique used to separate a soluble, dissolve solids from a solution.

Which separation technique can be used to separate a dissolved solid from a solution?

Crystallisation.

For crystallisation to happen, the solid must be what?

It must be more soluble in hot solvent than in cold so that it can decompose when heated.

Explain the process of crystallisation.

• Solution is heated in an evaporating dish for a solvent to evaporate. Saturated solution left behind.

• When crystals begin to form, remove dish from heat and leave to cool.

• Filter crystals out of the solution and leave in a warm place to dry and pat dry with filter paper.

Explain how you could separate a soluble solid from a solution.

• Crystallisation. Pour solution into an evaporating dish and heat gently.

• When crystals begin to form, remove dish from heat and leave to cool.

• Filter crystals out of the solution and leave in a warm place to dry (oven) and pat dry with filter paper.

Describe how to obtain a sample of pure, dry sodium chloride crystals can be obtained from the filtrate.

• Heat solution.

• Leave solution to cool.

• Filter off crystals and pat dry between filter papers or leave to dry in an oven.

What is the purpose of simple distillation?

A separation technique used to separate a solvent from a solution.

Which separation technique can be used to separate a solvent from a solution?

Simple distillation.

Which separation technique can be used to separate a liquid from a solid?

Simple distillation.

How can seawater be purified?

Simple distillation.

What is the liquid collected in the beaker at the end of simple distillation known as?

Distillate.

A condenser is used during distillation. Where does cold water enter and exit the condenser?

Water enters at the bottom and leaves at the top.

During distillation, a bunsen burner is used to heat the flask. Give an alternative piece of apparatus that could be used to heat the flask.

Electric heater or blow torch.

Explain why a condenser is used during simple distillation.

To cool the water vapour back to liquid.

Explain how ethanol be separated from water.

• Simple distillation.

• Mixture is boiled and since ethanol has a lower boiling point than water, ethanol evaporates first.

• Ethanol vapour cools in the condenser, condensing back into a liquid before being collected.

What is the purpose of fractional distillation?

A separation technique used to separate two or more liquids with different boiling points in a mixture.

What is the difference between fractional and simple distillation?

Simple distillation is used to separate ba solvent from a solution whereas fractional distillation is used to separate two or more liquids with different boiling points in a mixture.

Which piece of equipment does fractional have that simple distillation does not?

Fractioning column.

How does fractional distillation separate oil?

Oil is heated until it evaporates into the fractioning column. The vapour rises up the column and condenses at differnet fractions, depending on the relative boiling point of each substance.

Explain the process of distillation.

• Solution is heated.

• Liquid with lowest boiling point evaporates producing a vapour which rises.

• Vapour passes through condenser to cool and condense, becoming a pure liquid that is collected in a beaker.

Devise a plan to separate pure water from this mixture, including a test to show that the water obtained is neutral.

• Distillation used.

• Solution in a flask is heated.

• Water evaporates.

• Pass water vapour into condenser where it will cool and condense back to a liquid.

• Water collected in beaker whilst solid remains in flask.

• To test if neutral, you could place the distilled water in a test tube. Either add a few drops of Universal Indicator to see if becomes the correct neutral colour or use a pH probe to see if its pH 7.

Describe how to separate an insoluble substance from a solution.

• Place filter paper in a funnel.

• Pour solution containing an insoluble substance through funnel into a conical flask.

• The insoluble substance will collect on the filter paper and the solution will collect in the conical flask.

Describe how a sample of pure dry nickel sulfate crystals can obtained from the mixture of nickel solution and excess solid nickel carbonate in the beaker.

• Filtration.

• Place filter paper in a funnel.

• Pour solution containing an insoluble substance through funnel into a conical flask.

• The insoluble substance will collect on the filter paper and the solution will collect in the conical flask.

• Crystallisation.

• Heat solution to leave crystals behind.

• Allow to cool. Dry crystals between filter papers and leave in a warm oven.

How could you separate salt from a mixture of salt and sand?

• Salt is soluble in water whereas sand isn’t.

• Add water to mixture. Filter solution so insoluble sand remains in filter paper whilst water and salt become the filtrate.

• Evaporated water to collet the salt crystals.

Explain how the water in sea water separates to produce the pure water in this apparatus.

Water boils/evaporates to form water vapour, leaving the salt behind. The water vapour condenses back to liquid, forming pure water.

Explain how the apparatus could be improved to increase the amount of pure water collected from the same volume of sea water.

• Use a Liebig condenser. This surrounds the test tube with beaker of iced/cold water.

• This increases the effectiveness of cooling by ensuring all the water vapour condenses.

At the end of distillation, pure water collects in the beaker. Explain how the apparatus will show that the liquid collected is pure water.

Use a thermometer to show that the temperature is 100°C (the boiling point of water).