P3 Flashcards
What is density?
How “packed” a substance is and how the particles are arranged.
What is the equation for density?
Density (kg/m3) = mass (kg) / volume(m3)
Density for solid
Very dense. Strong forces of attraction hold the particles in a fixed arrangement. They have little energy so can only vibrate.
Density for liquid
Somewhat dense. Weaker forces of attraction between particles so they can move past each other and form irregular arrangements. They have somewhat more energy so can move around slowly and in random directions.
Density of gases
Low density. Almost no forces of attraction between particles which means they are free to move in random directions with higher speeds.
Required practical activity 5: use appropriate apparatus to make and record the measurements needed to determine the densities of regular and irregular solid objects.
- Use a balance to measure its mass. 2. If it is a regular shape do hXwXl and measure with a ruler. 3. If it’s irregular submerge the object in a eureka can filled with water. 4. The water displaced will be transferred into a measuring cylinder. 5. Record that volume and it is now the object’s volume. 6. Density equation.
Required practical activity 5: use appropriate apparatus to make and record the measurements needed to determine the densities of liquids.
- Place a measuring cylinder on a balance and zero it. 2. Pour 10ml of liquid into cylinder and measure mass. 3. Pour another 10ml in and measure mass. 4. Continue this and take an average of the densities.
What are the 5 changes of state?
- Freezing. 2. Melting. 3. Evaporating. 4. Condensing. 5. Sublimating.
What’s the difference between changes of state and chemical changes?
Changes of state are physical changes which differ from chemical changes because the material recovers its original properties if the change is reversed.
What is internal energy?
Energy is stored inside a system by the particles (atoms and molecules) that make up the system.
What 2 types of energy does internal energy contain?
Kinetic energy and potential energy of all the particles
What 2 things can heating do?
Heating changes the energy stored within the system by increasing the energy of the particles that make up the system. This either raises the temperature of the system or produces a change of state.
What is specific heat capacity?
The specific heat capacity of a substance is the amount of energy required to raise the temperature of one kilogram of the substance by one degree Celsius.
What is latent heat?
The energy needed for a substance to change state.
What is specific latent heat?
The specific latent heat of a substance is the amount of energy required to change the state of one kilogram of the substance with no change in temperature.
Name the names and units for E =m L
Energy for a change in state in joules. Mass in kilograms. Specific latent heat in J/Kg.
What is specific latent heat of fusion?
Change of state from solid to liquid.
What is specific latent heat of vaporisation?
Change of state from liquid to vapour
If you increase the temperature of a gas…
You give particles more kinetic energy so they move faster and collide more (exerting forces) which means pressure increases.
What are pressure and volume in gases?
Inversely proportional. pV= constant.
Name the names and units for pV=constant.
Pressure in pascals. Volume in meters cubed.
What can happen with a gas and changes in pressure?
The pressure produces a net force at right angles to the wall of the gas container (or any surface). A gas can be compressed or expanded by pressure changes.
What happens if you do work on a gas?
Doing work on a gas increases the internal energy of the gas and can cause an increase in the temperature of the gas. A force is applied so particles have more kinetic energy and move faster.
