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Question 1

What is a molecule?

Answer 1

Molecules are collections of atoms, strongly joined together, or bonded.

Question 2

What is the formula for density

Answer 2

Density (kg/m^3)=mass(kg) /volume(m^3)

Question 3

What is kelvin?

Answer 3

It’s temperature +273
So 0 degrees = 273 kelvin(K)

Question 4

How do you calculate with specific heat capacity?

Answer 4

Change in thermal energy (J) = mass (kg) x specific heat capacity (J/kg.C) x change in temperature(.c)

Question 5

How do you calculate with specific latent heat?

Answer 5

Thermal energy for a change in state(J) = mass (kg) x specific latent heat (J/kg)

Question 6

How do you calculate with pressure and volume?

Answer 6

Pressure (Pa) x volume(m^3) = constant

Question 7

How do you calculate liquid pressure?

Answer 7

Pressure (Pa) = height of column (m) x density of liquid (kg/m3) x gravitational field strength -g- (N/kg)

Question 8

How do you calculate pressure?

Answer 8

Pressure(Pa) = force(N)/area(m^2)

Question 9

An object floats if:

Answer 9

(Pressure at bottom x area at bottom) - (pressure at top x area at top) = weight

Question 10

How do you calculate average speed?

Answer 10

Distance travelled (m/s) = total distance (m) / total time (s)

Question 11

What is a vector?

Answer 11

A quantity with magnitude(size) and direction

Question 12

What is a scalar?

Answer 12

A quantity with magnitude (size) but no direction

Question 13

How do you calculate acceleration if you know the change in velocity?

Answer 13

Acceleration (m/s^2) = change in velocity (m/s) / time (s)

Question 14

How do you calculate acceleration?

Answer 14

Acceleration(m/s2) = final velocity(m/s) - initial velocity (m/s) / time (s)

Question 15

Equation of motion

Answer 15

(Final velocity (m/s))^2 - (initial velocity(m/s))^2 = 2 x acceleration (m/s^2) x distance (m)

Question 16

What is specific heat capacity?

Answer 16

The amount of energy needed to raise the temperature of 1kg of a material by 1k of its specific heat capacity

Question 17

What does specific heat capacity depend on?

Answer 17

-the type of material
-the mass of the material
-the temperature rise

Question 18

What is internal energy?

Answer 18

The internal energy is the energy that relates to the motion, vibration , rotation and arrangement of particles.

Question 19

Where does specific heat capacity make a difference?

Answer 19

In stuff like saucepans that need low specific heat capacities to heat up quickly

Question 20

What is sublimation?

Answer 20

Solid to gas

Question 21

What is gas to solid called?

Answer 21

Depositing

Question 22

What is latent heat?

Answer 22

The specific heat of fusion(or melting) is the energy transferred when 1kg if a substance changes from the solid state to the liquid state, or from the liquid state to the solid state

Question 23

How is specific latent heat capacity different from specific heat capacity?

Answer 23

Both specific latent heat and specific heat capacity involve energy changes for 1kg of a substance.

Latent heat is about change of state, and heat capacity is about change of temperature

Question 24

Why do gases exert pressure?

Answer 24

When you blow up a balloon it gets bigger. You are increasing the number of air particles in the balloon. The particles collide with the inside surface of the balloon.

Question 25

What is the pressure of gas measured in?

Answer 25

Pascals(Pa) One pascal equals one newton per square metre (N/m^2)

Question 26

What is a kilopascal(kPa)?

Answer 26

1 kPa = 1000 Pa

Question 27

How does temperature affect gas pressure?

Answer 27

If the temperature of a gas increases, the gas particles have a higher average speed. They collide more frequently with the sides of the container. These collisions produce a bigger force over a certain area. This produces a bigger pressure.

Question 28

What happens when the pressure of a gas is at 0

Answer 28

This is known as absolute zero and is reached -273.24 degrees or 0 kelvin

Question 29

What is height difference in gas?

Answer 29

Height difference is a measure of the gas pressure

Question 30

How are pressure and volume related?

Answer 30

-as the volume doubles, the pressure halves -as the volume halves The pressure doubles -pressure and volume are inversely proportional

Question 31

Why are pressure and volume inversely proportional?

Answer 31

The collisions of the gas particles produce a force that is at right angles to the surface. If you halve the volume, you double the number of collisions per second between the gas particles and the container.

Question 32

How does doing work on a gas affect the temperature?

Answer 32

When you use a bicycle pump you might notice that the valve gets hot. You can increase the internal energy of a gas by: -heating it -doing work on it -if you apply a force to the link and move it in you do work on the gas and it gets hotter. The average speed of the particles will increase because their kinetic energy increases when they collide with the moving piston, so the temperature is higher.

Question 33

What is atmospheric pressure?

Answer 33

The gases if the atmosphere exert a pressure called atmospheric pressure. On the surface of the Earth atmospheric pressure is 101,325 Pa Which is about 100,000 Pa or 100 kPa. This means that there is a force of about 100,000N on each square metre of the Earths surface. That is the weight of 10 cars.

Question 34

Atmospheric pressure on a can:

Answer 34

-When you have an open can, the forces on the can are equal in all directions so it’s shape does not change -if you pump the air out of the can it collapses

Question 35

What happens to atmospheric pressure as you go up?

Answer 35

-Near the top of Mount Everest atmospheric pressure is 33kPa. -As you go away from the earth the atmospheric pressure decreases. There is less air above pushing down. -Think about a 1m thick layer of air that is 1km away from the earth. There is a pressure difference between the top of the layer and the bottom of the layer because the air pressure at the bottom is greater. The layer does not move because the upwards force balances the weight of the air above it pushing down.

Question 36

What is liquid pressure?

Answer 36

The water in an ocean(and anywhere else) exerts a liquid pressure. Water molecules are very close together. They collide with eachother, the container, and anything in the water. Liquid pressure acts in all directions.

Question 37

What happens to liquid pressure as you go deeper?

Answer 37

-As you swim deeper in a swimming pool there is a greater pressure on your ear drums. -You can show that the pressure increases in depth by making holes in a bottle of water. -The pressure at the top is less, so the water does not travel as far horizontally as the water at the bottom. -this is similar to what happens in the atmosphere: as you climb down a mountain the air pressure increases. -The molecules in any layer in a liquid are being compressed by the weight of all the liquid above that layer. -This pushes the water molecules together so the pressure is bigger. -There is a limit to the pressure that the human body can withstand.

Question 38

What happens to pressure in liquids of different densities?

Answer 38

When you compare two liquids with different densities, the pressure at a particular depth will always be greater in the denser liquid. This is because in the denser liquid, there is a greater weight of liquid pushing down. The pressure due to a column of mercury is bigger than the pressure due to a column of water

Question 39

How can you find the difference in pressure between two different depths?

Answer 39

You can find the difference in pressure between two different depths by calculating the pressure at each depth and subtracting the smaller pressure from the larger pressure.

Question 40

How do you find the total pressure?

Answer 40

-the total pressure would be equal to the pressure due to the liquid and the pressure due to the pressure of the atmosphere

Question 41

Why is there an upwards force on a floating object?

Answer 41

Anything that is floating, such as a super-tanker on you, must have an upwards force in it to balance its weight. You can explain where this upthrust comes from using ideas about pressure in liquids and gases.

Question 42

Why do some objects float and others sink?

Answer 42

-A submarine “floats” at different depths in the ocean. If the pressure difference together with the area is big enough, then the net force will be enough to balance the weight. -To go back to the surface you need to pump air back into the tanks. -Submarines carry tanks of compressed air to do this. -this is how fish adjust their depth in the water. They have a swim bladder and can vary the amount of gas in it, just like the tanks of a submarine as water is expelled from them.