The particle model of matter Flashcards
Almost everything is made of ___ .
particles
Particles can be __ , ___ or ___.
atoms
molecules
ions
Particles behave differently in___ , __ and ___
solids
liquids
gases
The __ explains the differences between solids, liquids and gases.
particle model
Water exists as a solid, liquid and as a gas. What name is used for solid water and gaseous water?
Solid water is ice. Gaseous water is steam.
In a __ , the particles pack together tightly in a neat and ordered arrangement. The particles are held together too strongly to allow much movement but the particles do vibrate.
solid
In ___, particles are quite close together and move with random motion throughout the container.
liquids
In ___ the particles move rapidly in all directions, frequently colliding with each other and the side of the container.
gases
The hotter a solid gets, the faster its particles vibrate. This means that solids __ when they are heated.
expand
So particles in __ can move around and can move over each other, allowing __ to flow and be poured.
liquids
liquids
Sand can be poured, but it is definitely a solid. Why is this?
Sand is made from tiny grains, and even though these can roll over each other, each grain of sand has a fixed shape.
Why is helium gas used inside party balloons?
Helium gas is lighter than the mixture of gases that make up air. The lighter helium gas is trying to move above the air making the balloon rise up.
What are models?
Models are used in science to help explain scientific concepts.
What is a control variable?
The control variable is kept the same during the experiment.
What is an independent variable?
The independent variable is changed during the experiment.
What is a dependent variable?
The dependent variable is tested or measured during the experiment.
Pressure in gases is caused by particles __ with the walls of the container.
colliding
Gas pressure is increased when the temperature __ or the volume of the container ___ .
increases
decreases
If air is pumped into a bike tyre, does it increase or reduce the air pressure inside the tyre?
The air pressure increases because more air particles are being added to the inside of the tyre.
What happens to the pressure of a gas if the temperature is increased?
The gas pressure increases. If a gas is heated, its particles move around more quickly. They hit the walls of their container harder and more often, which increases the pressure.
___ is the name given to the force exerted by gas particles colliding with the wall of their container.
Gas pressure
Pressure is force exerted over an ___ .
area
What would happen to the pressure inside a car tyre if more gas is added?
The pressure would increase because there are more gas particles pushing on the inside of the tyre.
How do the particles of a gas move?
The particles travel in straight lines, bouncing off each other and the sides of the container so the movement is random.
How does temperature affect pressure?
Increasing the temperature of a gas increases the pressure and the energy of the gas particles.
These higher energy particles move faster, colliding harder and more often with each other and the walls of the container.
Write out what you think would happen to the appearance of the beach ball after 30 minutes in the freezer.
When an inflated beach ball is placed into the freezer for 30 minutes, it will appear ___
This is because when the gas inside the ball has cooled, the pressure has ___
This is because the particles of gas have __ energy so there will be __ collisions with the walls of the container.
deflated
decreased
less
less
What is a hypothesis?
In science, a hypothesis is an educated guess that you can test by investigating.
Solids, liquids and gases change state when they are __ or __ .
heated
cooled
Processes such as evaporation and boiling change the __ of substances.
state
A ___ model can be used to show how solids, liquids and gases change state.
particle
What is the process used to melt the chocolate?
Heating is used to melt the chocolate. When a solid is heated, it absorbs energy and it melts, turning into a liquid.
Which changes of state occur when a substance is cooled down?
Condensing and freezing.
When a liquid is heated, it boils. Describe what happens to the movement and arrangement of the particles during boiling.
When heated, the particles gain energy and become widely spaced. When the particles have gained enough energy, they move much faster in straight lines breaking away from the other particles. When a liquid is boiling, some of its particles enter the gas state.
Some solids change directly into a gas without becoming a liquid first. This process is called ___ .
sublimation
Solid carbon dioxide is called ___ .
dry ice
What is condensing?
If a gas is cooled, it transfers energy to the surroundings, and turns into a liquid.
What is freezing?
If the liquid is cooled, it transfers energy to the surroundings, and turns into a solid.
Cooling transfer energy to the surroundings so these processes y are __ .
exothermic
What is melting?
When a solid is heated, it absorbs energy and it melts, turning into a liquid.
What is boiling?
If the liquid is heated, it absorbs more energy and it boils, turning into a gas.
Heating absorbs energy from the surroundings so these processes y are __ .
endothermic
What is the opposite change of state to condensing?
Boiling is the opposite of condensing. During condensing, a gas changes into a liquid. During boiling, it is the other way round.
Water covers more than __ of the Earth’s surface. The most common locations are in oceans, rivers, lakes and glaciers.
70%
Water is most dense at __ C
4C
Water has a ___ , allowing some small insects to walk on its surface.
high surface tension
