Science Test - Particles of Matter Revision

What is a physical property of a substance?

A property that can observed or measured without changing the chemical identity of the substance, for example colour or state of matter.

What is air pressure?

Air pressure is the results of the particles in a gas colliding with the walls of the container. The more particles are moving the greater the collisions with the walls of the container, the greater the air pressure. Heating increases the air pressure, cooling will decrease the air pressure inside the container.

What are the four postulates of the particle theory of matter?

All matter is made up of tiny particles too small to see, there are spaces between the particles, the particles of matter are in constant motion and there are attractive forces between particles.

What is matter?

Anything that has mass and volume.

What is the difference between boiling and evaporation?

Boiling is different from evaporation, evaporation only occurs at the surface of a liquid, eg a puddle of water will evaporate in the sun, boiling is every particle in the liquid has enough energy to become a gas.

Gases information:

Gases do not keep their shape, they completely fill the container they are in, can flow, spread out quickly from where they started which is called diffusion, and can be compressed. The particles in gases have lots of energy and are moving faster than the particles if solids and liquids. There are no attraction forces so they move freely in any direction until they hit something, and then change direction.

Two examples of more viscous than water?

Honey and oil.

What is density?

How much matter there is in a specified volume.

Liquids information:

Liquids do not keep their shape, they take they shape of the container they are in, flow, and cannot be compressed. The particles in liquids are still found packed relatively tightly together, but are able to move over each other . As the particles are close with no space between them, liquids cannot be compressed.

Two examples of less viscous than water?

Method and xylenol.

What are the two properties?

Physical and chemical.

What is sublimation?

Skipping from gas to solid and solid to gas, excluding liquid.

Solids information:

Solids keep their shape unless they are broken, hit, heated, cut etc, and do not flow nor can they be compressed and change volume. The particles in solids are tightly packed in a fixed pattern with strong forces between the particles, stopping them from moving any more than vibrating. The more heat energy the faster the vibration of the particles.

What is malleability?

The ability of a substance to be hammered or bent into a thin sheet without breaking.

For something to float does it have to have less or more density than the liquid or gas causing it to float?

The floating thing must be less dense than what it is floating on.

Explain how a thermometer works in terms of particles etc:

The level of a thermometer rises when heat weakens then attractive forced between particles and they become energised, creating more space between other particles and expanding. As they become energised, they collide with each other and the walls of the thermometer and try to escape the hot area by rising up the tube of the thermometer. The level of a thermometer lowers when a cold temperature strengthens the attractive forces between particles causing the liquid to contract and take up less space.

What is the particle theory of matter?

The particle theory of matter describes how the particles of matter behave which explains why different states have specific properties in terms of how much energy particles have and how strong the attraction is between these particles.

Why is weight not a reliable way to measure matter?

Weight can be altered by factors like location or temperature, matter however can not be.

What is diffusion?

The spreading out of a substance from an area with lots of particles to an area of very few or no other particles. This happens in both gases and liquids where the particles are free to move. The more heat energy that a substance contains, the faster the particles are moving and so the faster the diffusion, the rate of diffusion will also be influenced by the weight/size of the particles involved.

What is a melting point?

The temperature at which a solid changes to a liquid.

What is a boiling point?

The temperature at which liquid changes to gas.

To go from a solid, to a liquid, to a gas, what must happen and visa versa?

There must be a gain of heat, and therefore an increase in energy, but in steps, melting. There must be a loss of heat, and therefore a decrease in energy, but in steps, condensation then freezing.

What is all matter made up of?

Tiny particles called atoms..

What is viscosity?

Viscosity is a measure of how easily a liquid a flows. A liquid with high viscosity does not flow easily. The attractive forces between the particles re stronger than in a liquid with low viscosity.

What is the cause of a flatline in graph of temperature?

When a substance is heated to the point where it melts or boils and so changes state, some of the energy is absorbed by the substance rather than actually increasing the temperature. This leads to a flat spot on the graph showing temperature.

Read over page 5 of the particles of matter revision three times now.

Yes.