What are the four main ideas of the Particle Model of Matter?
- A substance is made from very tiny particles called ‘atoms’ and ‘molecules’.
- The particles attract each other.
- Between particles, there is empty space with no matter between them.
- Particles have energy and move all the time; they move faster when given more energy.
What determines the phase of a substance?
The arrangement of the particles
What are the three phases of matter?
- Solid
- Liquid
- Gas
Give examples of solids, liquids, and gases.
- Solids: gold, plastic, wood
- Liquids: water, acid, cold drinks
- Gases: oxygen, carbon dioxide, methane
What is the composition of water in terms of its molecules?
Water consists of hydrogen and oxygen in a ratio of 2 hydrogen atoms to 1 oxygen atom, written as H2O.
What is a characteristic of solids?
Solids keep their shape.
How are the particles arranged in a solid?
The particles are packed closely together with small spaces between them.
What is the movement of particles in solids?
Particles vibrate in a fixed space.
What defines the arrangement of particles in liquids?
Particles stay close together but move about freely.
What is the force of attraction like in liquids compared to gases?
The forces between particles in liquids are stronger than in gases.
What are the characteristics of gases?
- Gases consist of small particles or molecules.
- Particles stay spread far apart.
- Particles move around very freely.
- Forces of attraction between particles are very weak.
What is diffusion?
Diffusion is the spontaneous moving, mixing, and spreading of one substance through another from a region of high concentration to a region of low concentration.
What is Brownian motion?
Brownian motion is the continuous random erratic motion of particles in liquids or gases caused by the impact of moving molecules.
What is the kinetic molecular theory of gases?
- Gases consist of particles in constant random motion.
- Gas particles collide elastically with each other and container walls.
- The total volume of gas particles is negligible relative to the container volume.
- There are no interactive forces between gas particles.
- Average kinetic energy of gas particles is proportional to absolute temperature.
How do gases exert pressure?
Gas pressure is due to the sum of collision forces from moving gas molecules.
What factors affect pressure in gases?
- Number of molecules
- Volume of the container
- Temperature
True or False: Increasing the volume of a gas container decreases pressure.
True
What happens to gas pressure when the temperature increases?
Pressure increases due to higher average kinetic energy of molecules.
To increase pressure, what can be done?
- Increase the force
- Reduce the area the force acts on
How does pressure change in liquids with depth?
Pressure increases at increasing depths because the liquid below must support all the water above it.
What is the formula for pressure?
Pressure (P) = Force (F) / Area (A)
What is the SI unit of pressure?
Pascal (Pa)
How do you determine the mass of a liquid?
Find the mass of the empty beaker, then the mass with the liquid, and subtract the former from the latter.
What is the SI unit for volume?
Cubic meter (m³)
