Solutions and Mixtures

  • Matter - anything that has mass and takes up space (volume)

STATES OF MATTER

  • Solid - keeps its shape (e.g. textbooks)

  • Liquid - flows and takes the shape of the container they are in (e.g. water)

  • Gas - spreads out and fills space (e.g. air freshener)

PARTICLE THEORY

  • All matter is made up of tiny particles

PURE SUBSTANCE

  • Made of only one type of particle

  • Example - distilled water

MIXTURE

  • Two or more substances joined but not chemically combined

  • Example: cereal

PHYSICAL CHANGE

  • A change where no new substance is formed

  • Example: ice melting into water

PARTICLE BEHAVIOUR

  • Particles are always moving or vibrating

  • They are held together by attractive forces

  • The amount of energy particles have determines whether matter is a solid, liquid or gas

SOLIDS

  • Particles are tightly packed together in a fixed pattern

  • Particles only vibrate in place, keeping their shape

  • Has fixed volume

  • hard to compress - low compressibility

  • Strong force of attraction

LIQUIDS

  • Particles are close to each other and slide past each other

  • Has no fixed shape, but takes shape of container

  • Has fixed volume

  • hard to compress - low compressibility

  • Force of attraction - strong enough to keep them together but weak enough to let them move

GAS

  • Particles in gas are far apart and move quickly in all directions

  • Has no fixed shape but takes shape of container

  • Has no fixed volume but takes shape of container

  • Easily compressed - high compression

  • weak force of attraction

Why does gas fill up a balloon?

  • moves freely in all directions - colliding with the inner walls

  • have very weak force of attraction between them

  • spread out to fill any available space

Why does ice keep its shape, but water doesn’t?

  • In ice, the molecules lose energy and fix into a rigid pattern (lattice) which holds a definite shape

  • In water, molecules have enough energy to slide past each other, so they flow and take shape of container

Why does perfume spread through a room?

  • Perfume spreads through a room due to diffusion

  • Perfume is a volatile liquid, and it quickly evaporates into a gas when released

  • These gas molecules then move from an area of high concentration (the spray bottle) to low concentration

BOUYANCY

  • Ability of an object to float on water or another fluid

How it works

  • when the object is placed in water, it pushes water aside

  • The water pushes back upward on the object

  • This upward push is called buoyant force

Floating and Sinking

  • strong buoyant force - object floats

  • Less buoyant force (than object) - object sinks

Density link

  • Objects less dense than water usually float

  • objects more dense than water usually sink

More particles - more density

Less particles - less density

  • Refers to the amount of matter in a given volume

  • It determines how tightly packed a substance is

SURFACE TENSION

  • Is the elastic-like force on the surface of water that allows small objects like insect to walk on it without sinking

VOLUME

  • The amount of 3D space occupied by an object, substance or enclosed area

IMMISCIBLE LIQUIDS

  • Mixture of two or more liquids, but they get separated, like in the density column

Surfactant

  • Substance that breaks the surface tension of a liquid, just like how the soap broke the surface tension in water when we added the paper clip and paper towel - THEY SANK!

MEASURING VOLUME

  • use a graduated cylinder/volumetric flask/ measuring cylinder

LENGTH - METRE

MASS - KG

VOLME - CM3

DENSITY - KG/M3 G/ML

DENSITY = MASS/VOLUME

MASS = VOLUME X DENSITY

MENISCUS = THE CURVED UPPER SURFACE OF A LIQUID COLUMN

SI REFRENCE - STANDARD MEASUREMENT BASED ON THE INTERNATIONAL SYSTEM OF UNITS

ACCURACY - description of how close a value is to the true value

CONTROLLED VARIABLE - A variable that is kept constant throughout an experiment

DEPENDENT VARIABLE - The variable that is being mentioned in an experiment; it changes as the independent variable changes

IDEPENDENT VARIABLE - The factor that is changed in an investigation to find out how it affect another factor (dependent variable)

PREDICTION - A statement that suggests what will happen in an experiment

MASS - amount of matter in a substance or object, measured in grams, kilograms or tonnes

ZERO ERROR - When you do not start at zero point

PARALLAX ERROR - This is a observational mistake occurring when an object, pointer or scale is read from an angle rather than straight on

SUBLIMATION

  • When a solid directly becomes gas without becoming a liquid first (e.g. dry ice/ solid - Co2

DEPOSITON

  • When a gas directly becomes a solid without becoming a liquid first (e.g. frost on a window)

  • This occurs when the particles gain/lose energy that they completely bypass the liquid middle ground

THREE GOLDEN RULES FOR THE PARTICLE MODEL

  • All matters are made up of tiny particles

  • The particles are always in a constant, random motion

  • there are empty spaces between the particles

ATTRACTION

  • The invisible pull of force that holds particles together

KINETIC ENERGY

  • Energy that particle has due to motion