Particles Of Matter: Experiment 2.1

• The topic is Particles of Matter

Evidence Matter is Made of Particles Experiment 2.1

• The aim is to investigate volume change when mixing 100 cm³ of peas and sand
• Add 100 cm³ of peas to a 250 cm³ measuring cylinder
• Add 100 cm³ of sand to another 250 cm³ measuring cylinder
• Carefully pour the sand into the measuring cylinder with peas, shake
• Record the total volume of the peas and sand mix
• When 100 cm³ of peas are added to 100 cm³ of sand, a volume of 180 cm³ was recorded
• Flammable liquids should be kept away from naked flames
• The aim is to investigate volume change when equal volumes of ethanol and water are mixed
• Add 50 cm³ of water to a 100 cm³ measuring cylinder
• Add 50 cm³ of ethanol to another 100 cm³ measuring cylinder
• Carefully pour the contents of one measuring cylinder into the other measuring cylinder
• Record the total volume of the water and ethanol mixture
• When 50cm³ of ethanol and 50cm³ of ethanol are mixed then a volume of less than 100cm³ was recorded
• Water particles fit into the spaces between the ethanol particles which are larger
• Everything is made of atoms, atoms can join to form molecules

Spacing Between Particles Experiment 2.2

• The aim is to compress solids, liquids, and gases in syringes
• Additional safety includes explosion risk when applying pressure to a liquid or a gas
• Gases can most easily be compressed
• There are large spaces between particles in a gas

Movement of Particles Experiment 2.3

• The aim is to compare movement of particles of matter
• The movement of particles from an area of high concentration to low concentration is diffusion
• Nitrogen dioxide molecules and air particles diffuse upwards and downwards
• Ammonia molecules are much smaller, and travel faster, than hydrogen chloride molecules
• In solids, particles do not move relative to one another, they simply vibrate
• In liquids, particles are moving
• This can be seen through the colour change as the particles spread upwards
• Particles in liquids do not move as fast as gas
• Copper sulfate is the solute in this experiment and water is the solvent

States of Matter: Solids, Liquids, and Gases

• Solids have a regular arrangement of particles all touching
• Solid particles can only vibrate
• Solids have fixed shape, fixed volume and are difficult to compress.
• Solids have strong attractions
• Liquids have an irregular arrangement of particles which can move around freely
• Liquids have a fixed volume, can change shape and are difficult to compress
• Liquids have weaker attractions
• Gas particles are moving freely and as far apart as possible and expand to fill all space available
• Gases can be easily compressed and have very weak attractions

Properties of Substances

• Millions of different substances all with very different properties
• The physical state of a substance, whether it is a solid, liquid or gas at room temperature, is an example of a property of that substance

Changing State

• Substances can be changed from one physical state into another using knowledge of properties known as melting and boiling points
• The melting point of a substance is the temperature that the substance turns from a solid into a liquid

Measuring Melting Points or Different Solids Experiment 2.4

• The aim is to compare the melting points of some pure substances
• Stearic acid, Salol, Sodium Chloride all use careful handling of chemicals to avoid skin irritation
• Hot equipment requires care
• Salol has a lower melting temperature than stearic acid and sodium chloride

Melting Point and Boiling Point of Salty Water/Tap Water Experiment 2.5

• The aim is to compare the melting point and boiling point of salty water and tap water
• At sea level the melting point of ice is 0°C
• Salty ice has a melting point of -7°C
• The boiling point of pure water is 100°C
• The boiling point of salty ice is 105°C
• Melting point of tap water was higher than salty water/ice
• Boling point of salty water is higher than pure water.
• Impurities lower the freezing point of a liquid and raise the boiling point of a liquid
• boiling point increases as more salt is dissolved in water.

Boiling Point of Flammable Liquid Experiment 2.6

• The aim is to determine the boiling point of flammable liquids, for example ethanol
• Condenser cools the vapour below its boiling point changing the gas back into a liquid
• The boiling point of ethanol is 78°C

Sublimation Experiment 2.7

• Sublimation takes place when a solid turns directly to a gas or a gas turns directly to a solid

Scientific Method

• Make an observation that generates a question
• Carry out some research to see if you can find an answer to that question, might come up with a hypothesis
• Plan an experiment that will allow you to answer the question
• Collect and analyse data from your experiment
• Draw a conclusion from your findings
• Report on your results

Investigating Evaporation or Investigating the Speed of Evaporation of a Liquid Experiment 2.8

• Particles on the surface of a liquid can gain energy, escape from the liquid and turn into a gas at temperatures below their boiling point which is called evaporation
• Factors which might affect the rate of evaporation: temperature, wind speed, and how much surface is exposed
• The aim: To compare the speed at which ethanol and water evaporate to find out if different liquids evaporate at different speeds
• The independent variable is the type of liquid (ethanol and water)
• The dependant variable is the time to evaporate
• Controlled variables are: volume of liquid (1 drop), surface area (filter paper), temperature (room temperature), and air speed (still)
• The method: place one drop of water on a piece of filter paper, place a drop of ethanol on a second piece, time how long each drop takes to evaporate
• The average ethanol evaporation time was 18.3s
• The average water evaporation time was 102.3s
• Ethanol evaporates faster than water
• Lower boiling point liquids evaporate faster
• Different liquids evaporate at different rates
• Surface: evaporation happens at the top of a liquid below boiling point
• Procedure needs to be written in the past tense, third person

Solution Investigation

• A solid which dissolves in a solvent is described as being soluble
• A solid which does not dissolve is said to be an insoluble solid
• In a solution the solid particles have dissolved
• In a suspension the solid particles are bigger and prevent light from passing through

Sugar Dissolving Investigation

• Factors affecting how quickly sugar (or other solids) dissolves: temperature of water, mass of sugar, volume of liquid, presence of milk, stirring