chemistry igcse 2 Flashcards
what is a kinetic particle theory
- describes the states of matter
- explains the differences in the properties of solids, liquids and gases
- explains the changes of state of matter
why does a solid have a fixed shape
the particles of a solid are closely packed and are arranged in a regular arrangement. The strong forces of attraction holds the particles together. It has enough kinetic energy to vibrate and rotate in a fixed position. The particles cannot move freely.
why does a solid have a fixed volume
the particles of the solid are regularly arranged and are closely packed meaning that it cannot be compressed.
why does liquid not have a fixed shape
the particles of a liquid are arranged irregularly. They have weaker forces of attraction than the particles of a solid and are not held in a fixed position meaning that the particles can move freely through out the liquid.
why does liquid have a fixed volume
the particles of a liquid are packed quite closely together meaning that they cannot be compressed
why does gas not have a fixed shape
the particles of the gas a spread far apart and have a weaker force of attraction. They have more kinetic energy than both solids and liquid meaning that the particles can move freely and fast, therefore the particles are not held in fixed positions.
why does gas not have a fixed volume
there are a lot of space between the particles compared to the particles of a solid and a liquid. They can easily be compressed, therefore it does not have a fixed volume.
what is the process called when a solid turns into a liquid
melting
what is the process called when a liquid turns into a solid
freezing
what is the process called when a gas turns to a liquid
condensation
what is the process called when a liquid turns into gas
evaporation / boiling
what are the differences of boiling and evaporation
boiling only occurs at the boiling point which is 100 degrees celcius. Boiling occurs throughout the liquid and occurs rapidly. Evaporation happens at temperatures below boiling point, occurs only on the surface of the liquid and occurs slowly.
how does the kinetic particle theory explain the change of state of a solid to a liquid
when a solid starts to melt, the heat is absorbed by the particles of a solid, the particles will start to vibrate faster in their fixed positions. There is an increase in their kinetic energy.
when the temperature is high enough, the vibrations of the particles will soon overcome the attractions between them. The particles will soon break away from their fixed positions.
the particles will no longer be in fixed positions .he substance is now a liquid. The particles can move freely throughout the liquid.
how does the kinetic particle theory explain the change of state of a liquid to a solid
the energy is given out by the particles of the liquid. the particles lose kinetic energy and will begin to move more slowly.
when the temperature is low enough, the particles will no longer be able to move freely. they start to settle in their fixed positions.
all the particles have settled int their fixed positions. the substance is now a solid. the particles can only vibrate and rotate in their fixed positions.
how does the kinetic particle theory explain the change of state of a liquid to gas
heat is absorbed by the particles of a liquid. the particles will start to move faster as the temperature increases, there is an increase in the kinetic energy.
when the temperature is high enough, the particles have enough energy to overcome forces of attraction holding them together.
the particles are now spread far apart. the substance is now a gas. the particles can move about in any direction.
what is the effect of temperature on the volume of a gas
when a gas is heated, the temperature increases. the particles gain more energy, therefore the volume of the gas increases.
what is diffusion
the random movement of particles from a region of high concentration to a region of low concentration
what the is effect of pressure on the volume of the gas
increase of pressure on the gas, the volume of the gas will decrease
what is an element
a substance that cannot be broken down into any other smaller subtstances
the experiment is held, a cotton will soaked in concentrated aqueous ammonia and a cotton wool soaked in concentrated hydrochloric acid, which one will diffuse faster?
the cotton wool soaked in concentrated aqueous ammonia will diffuse faster as it had a lighter relative molecular mass.
what is an atom
the smallest particle of an element that has the chemical properties of that element
what is a molecule
a group of two or more atoms that are chemically combined
compositions and decompositions of an element
composition
- an element contains only one type of atom
- the smallest particle in an element is an atom
decomposition
- an element cannot be broken down into any other smaller substances
what is a mixture
a mixture is made up of two or more substances that are not chemically bonded
