Chemistry Y11 Topic 2

What is matter?

Anything that has mass and takes up space

What are the three states of matter?

Solid, liquid, gas

How are particles arranged in a solid?

Closely packed in a fixed lattice

How do particles move in a solid?

Vibrate about fixed positions

Why do solids keep a fixed shape?

Strong attractive forces hold particles in place

Why can solids not be compressed?

Particles are very close together

How are particles arranged in a liquid?

Close together in a disordered arrangement

How do particles move in a liquid?

Move and slide past each other

Why do liquids take the shape of the container?

Particles are mobile but still close together

Why do liquids have a fixed volume?

Particles are held together by attractive forces

Why can liquids only be slightly compressed?

Little space between particles

How are particles arranged in a gas?

Far apart with no fixed arrangement

How do particles move in a gas?

Rapidly and randomly in all directions

Why do gases fill the container?

Negligible attractive forces between particles

Why can gases be compressed easily?

Large spaces between particles

What causes gas pressure?

Particles colliding with container walls

What is melting?

Solid changing to liquid

What is freezing?

Liquid changing to solid

What is boiling?

Liquid changing to gas throughout the liquid

What is evaporation?

Liquid changing to gas at the surface

What is condensation?

Gas changing to liquid

What is sublimation?

Solid changing directly to gas

What theory explains changes of state?

Kinetic theory

What happens to particles when heat is added?

They gain kinetic energy and move faster

What is a heating curve?

A graph showing temperature change as heat is added

Why are there flat sections on a heating curve?

Energy is used for phase change (latent heat)

What happens during melting on a heating curve?

Temperature stays constant while solid melts

What happens during boiling on a heating curve?

Temperature stays constant while liquid evaporates

What is latent heat?

Energy used to change state without changing temperature

What is a pure substance?

A substance containing only one element or compound

How can purity be identified using melting point?

Pure substances have a sharp melting point

How do impurities affect melting point?

Lower the melting point

How do impurities affect boiling point?

Raise the boiling point

How do impure substances melt or boil?

Over a temperature range

What is diffusion?

Movement of particles from high to low concentration

What causes diffusion?

Random particle motion

What is Brownian motion?

Random movement of particles caused by collisions with smaller particles

Who observed Brownian motion?

Robert Brown

How does particle size affect speed?

Smaller particles move faster

How do you calculate molecular mass?

Add the atomic masses of all atoms in the molecule

What is the molecular mass of HCl?

36.5

What is the molecular mass of NH3?

17

What is the molecular mass of H2O?

18

What is the test for hydrogen gas?

Lighted splint gives a squeaky pop

What is the test for oxygen gas?

Glowing splint relights

What is the test for carbon dioxide gas?

Limewater turns milky

What is the test for ammonia gas?

Damp red litmus paper turns blue

What is the test for chlorine gas?

Damp litmus turns red then bleached

What is the test for water vapour?

Cobalt chloride paper turns blue to pink

What is the test for sulfur dioxide?

Acidified potassium manganate(VII) turns purple to colourless

What is an element?

A substance containing only one type of atom

Can elements be decomposed chemically?

No

What is a compound?

Two or more elements chemically bonded

Can compounds be decomposed chemically?

Yes

What is a mixture?

Two or more substances physically combined

Can mixtures be separated physically?

Yes

Do mixtures have fixed composition?

No

Do pure substances have definite properties?

Yes

How do you separate an insoluble solid from a liquid?

Filtration

What are the two parts of filtration?

Residue and filtrate

How do you obtain a dissolved solid from a solution?

Evaporation

How do you obtain the solvent from a solution?

Distillation

What separates liquids with different boiling points?

Fractional distillation

What separates immiscible liquids?

Separating funnel

What purifies impure solids?

Recrystallisation

What is chromatography used for?

Separating coloured substances

What indicates a pure substance in chromatography?

One spot on the chromatogram

What indicates a mixture in chromatography?

More than one spot

What must the origin line be drawn with in chromatography?

Pencil

Why must the origin line be above the solvent?

To prevent the sample dissolving directly into the solvent

What is the paper used in chromatography called?

Chromatogram

What is the formula for Rf value?

Distance travelled by spot divided by distance travelled by solvent

What is the maximum possible Rf value?

1