CP12a Particles and Density Flashcards
Density calculation
Density = mass/volume
Density is measured in:
kilograms/metres cubed (kg/m3)
Mass is measured in:
kilograms
What factor affect the density of sea water?
Its temperature and saltiness
Explain why liquids and gases can flow but solids cannot
In liquids, the forces of attraction between the particles are not strong enough to keep them in fixed position. In gases there are no forces of attraction. Particles in solids are held closely together by forces of attraction
Explain why gases can be compressed but solids and liquids cannot
The particles in gases are far apart whereas the particles in both solids and liquids are very close together
Arrangement of solids
Regular and close together
Movement of solids
Particles vibrate in a fixed position
Which state of matter can be compressed?
Gas
Arrangement of liquids
Random and close together
Movement of liquids
Move around eachother
Arrangement of gases
Random and far apart
Movement of gases
Fast in all directions
Density
The mass of a certain volume of the substance
Which state of matter is usually the most dense state?
Solid
Which state of matter is usually the least dense?
Gas
Which substance in solid form is less dense than its liquid form?
Ice (water)
Explain how the arrangement of particles in a liquid explain its properties
Particles in a liquid are random and close together. This means they can move past eachother therefore liquids can flow and take the shape of their container. The fact the particles are close together means liquids cannot be compressed
Explain why a substance becomes less dense when it changes from a liquid to a gas
It becomes less dense because the particles in a gas are spread out even further apart than in a liquid where the particles are close together
CORE PRACTICAL: INVESTIGATING DENSITIES
Method to measure the densities of liquids
1) Put an empty beaker on a balance, and set the balance to zero
2) Use a measuring cylinder to measure 50cm3 of a liquid and then pour it into the beaker
3) Write down the reading on the balance. This is 50cm3 of the liquid
CORE PRACTICAL: INVESTIGATING DENSITIES
Method to measure the densities of liquids
1) Find the mass of the solid
2) Stand a displacement can on the bench with its spout over a bowl and fill it with water
3) Hold a measuring cylinder under the spout and drop object in to the can (if it floats push it under water)
4) The water collected in measuring cylinder is the same as the volume of the object
