Solids, Liquids and Gases Flashcards
(40 cards)
Equation for density:
Density = mass (kg/g) / volume(m³/cm³)
PRACTICAL: investigate density using direct measurements of mass and volume
Calculating the Density of Regularly Shaped Objects:
Calculating the Density of Regularly Shaped Objects:
- Density = Mass/Volume
- Measure mass using a balance
- Measure the dimensions of the object using an appropriate measuring device (e.g. ruler)
- Repeat & take an average
PRACTICAL: investigate density using direct measurements of mass and volume
Calculating the Density of a liquid:
Calculating the Density of a liquid:
- Density = Mass/Volume
2 Measure mass of empty measuring cylinder using a balance - Measure mass of full measuring cylinder using a balance
- Calculate mass of liquid = full cylinder - empty cylinder
- Measure the volume using the measuring cylinder from the bottom of the meniscus
- Repeat & take a average
Equation for pressure:
Pressure (Pa) = Force (N) / Area (m²)
High pressure
Great for cutting
Low pressure
Will stop you sinking
Explain how the pressure at a point in a gas or liquid at rest acts equally in all directions.
- When they collide with something, particles in a gas or liquid exert a force on it
- When you add all of the forces due to collisions with a surface, the resultant is equal in all directions equal
- Therefore, pressure is equal in all directions
Equation for pressure difference:
Pressure difference (Pa) = Height (m) x Density (kg/m³) x Gravitational field strength (N/kg)
PAPER 2 What happens to the particles in an object when heat is applied?
- When heat is applied to an object, particles gain kinetic energy
- This makes the particles in the object vibrate more quickly
- If enough energy is supplied, the object can experience a change in state
PAPER 2 Solid → Liquid
Melting
-Solid is heated, some intermolecular bonds are broken
PAPER 2 Liquid → Gas
Boiling
-Liquid is heated, the remaining intermolecular bonds are broken
PAPER 2 Evaporation & its effect on particles…
- Evaporation occurs when gas particles escape from a liquid
- Evaporation can occur at temperatures lower than the boiling point
- Particles near the surface of the liquid carry the most kinetic energy
- When particles evaporate from the liquid, a cooling effect occurs
PAPER 2 What happens to temperature when a substance is heated or changes state?
- When you heat a substance, temperature rises.
- If, when heating a substance, the state changes, temperature does not change until it has changed state.
- This is because the energy is being used to break the bonds between particles.
PAPER 2 Describe the arrangement & motion of particles in solids
- Strong forces of attraction between particles
- Regular arrangement
- Particles closely packed together
- Vibrate about fixed positions
- This is why solids keep their shape & cannot be compressed
PAPER 2 Describe the arrangement & motion of particles in liquids
- Forces between particles not strong enough to hold in place
- Irregular arrangement
- Particles closely packed together
- Particles can move past each other
- This is why liquids can flow, take the shape of their container & cannot be compressed
PAPER 2 Describe the arrangement & motion of particles in gases
- Weak forces between particles
- Irregular arrangement
- Particles spread out
- Particles move randomly
- This is why gases can flow, take the shape of their container & can be compressed
PAPER 2 PRACTICAL: obtain a temperature-time graph to show the constant temperature during a change of state
- Fill a beaker with ice
- Add a thermometer to the beaker & measure the temperature of the ice
- Using a Bunsen burner, gently heat the ice cubes
- Record the temperature at regular intervals
- Record the temperature at which the ice begins to melt
- Eventually all the ice will melt to form water
- Continue heating until the water begins to boil
- Record this temperature
- The results can be plotted on a temperature-time graph
PAPER 2 What is specific heat capacity?
The energy required to raise the temperature of 1Kg of the substance by 1*c
(Every material has its own specific heat capacity)
PAPER 2 Equation for specific heat capacity:
Energy transferred (J) = mass (kg) x Specific Heat Capacity (J/Kgc) x Temperature change (c)
AQ = mcAT
PAPER 2 PRACTICAL: investigate the specific heat capacity of materials including water and some solids
- Use c = E/mAT
- Measure energy using the Joulemeter
- Measure time using a stopwatch
- Measure mass using a balance
- Measure change in temperature using final temperature - initial temperature & a thermometer
- Repeat & take an average
What type of motion are ideal gas molecules in?
A constant state of random motion
What happens to energy during collisions between ideal gas molecules?
No energy is lost; the collisions are elastic.
How does temperature affect the speed of gas molecules?
Higher temperature means faster molecules (more kinetic/internal energy).
Do ideal gas molecules experience attractive forces?
No, there are no forces of attraction between particles.
