5. Solids, Liquids And Gases

Question 1

What is the formula for density?

Answer 1

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

Question 2

What are the units for density?

Answer 2

Kg/m^3 or G/cm^3

Question 3

How can you find the density of an object?

Answer 3

Weigh the object for the mass
Submerge the object in water and measure the displacement of the water to find the volume
Do mass/volume

Question 4

How can you calculate the mass of an object when given the density and volume?

Answer 4

Do density*volume

Question 5

How can you find the volume of an object when given the density and mass?

Answer 5

Do mass/density

Question 6

What is the name of the object you can use to find the displacement of water when attempting to calculating density?

Answer 6

Eureka Can

Question 7

What method can you use to calculate density?

Answer 7

1. Fill a Eureka Can to just below the spout
2. Place a measuring cylinder by the spout to catch escaped water
3. Weigh the initial dock when dry on a flat surface with a balance that reads 0 at the start
4. Empty out the measuring cylinder, line it up with the water spout of the Eureka can
5. Place the rock into the Eureka can, and ensure that the rock is fully submerged in the water. (Ensure that your fingers are not in the water)
6. Read the value of the water in the measuring cylinder from eye level. If a meniscus is present read the value of the water from the bottom

Question 8

What is pressure?

Answer 8

Pressure is the force per unit area

Question 9

What is the equation for pressure?

Answer 9

Pressure is force/area

Question 10

If the area is measured in m² then what is the unit for pressure?

Answer 10

Pascals

Question 11

What is 1 pascal?

Answer 11

1N/m²

Question 12

If the the area is measured in cm² then what is the unit for pressure?

Answer 12

N/cm²

Question 13

Using the idea of pressure, explain the design of a typical drawing pin.

Answer 13

A drawing pin has one end that is blunt and one end that is sharp. The blunt side has a larger surface area, resulting in the force being distributed more evenly so force and therefore more pressure can be exerted. The sharp side has a smaller surface area so more pressure can be exerted onto the pin

Question 14

Why do mountain climbers need to take canisters of oxygen with them?

Answer 14

This is because the air becomes thinner as you go higher up, and less oxygen will be inhaled and this amount wouldn’t be sufficient for the body to function properly, so oxygen is compressed and taken with

Question 15

What is the name of the pressure the air around us exert?

Answer 15

Atmospheric pressure

Question 16

Convert 1 atm into Pa.

Answer 16

≈100,000 Pa

Question 17

True or false: The pressure at a point in a gas or a liquid acts equally in all directions.

Answer 17

True

Question 18

What is the equation for fluid pressure?

Answer 18

Fluid pressure = density (kg/m³ x gravitational field strength (N/kg) x depth (m)

Question 19

True or false: The equation pressure = ρgh gives you the pressure due to the water.

Answer 19

True

Question 20

What is the equation for total external pressure?

Answer 20

P(total) = P(liquid) + P(atmospheric)

Question 21

What is a manometer?

Answer 21

A U-shaped tube that uses a
reference liquid to find the pressure
difference between a gas inlet and
atmospheric pressure

Question 22

What is the equation for pressure difference in a fluid?

Answer 22

ΔP = ρgh

Question 23

How is gas pressure related to atmospheric pressure and pressure difference?

Answer 23

P(gas) = P(atmospheric) ± ρgh (add if fluid is higher on open side, subtract if fluid is lower on open side)

Question 24

What is a barometer?

Answer 24

A barometer is a scientific instrument that is used to measure the atmospheric pressure.

Question 25

What is the purpose of a barometer?

Answer 25

The purpose of a barometer is to measure atmospheric pressure and to help forecast changes in the weather.

Question 26

What is a mercury barometer?

Answer 26

A mercury barometer is a type of barometer that uses a vertical glass tube filled with mercury to measure atmospheric pressure.

Question 27

What is an aneroid barometer?

Answer 27

An aneroid barometer is a type of barometer that uses an airtight metal capsule to measure atmospheric pressure.

Question 28

What features should a detailed particle diagram include?

Answer 28

Arrangement

Question 29

How are particles arranged in a solid?

Answer 29

Tightly packed in a fixed pattern

Question 30

How are particles arranged in a liquid?

Answer 30

Close together

Question 31

How are particles arranged in a gas?

Answer 31

Far apart

Question 32

What is melting?

Answer 32

Solid → Liquid (energy added)

Question 33

What is freezing?

Answer 33

Liquid → Solid (energy removed)

Question 34

What is boiling/evaporation?

Answer 34

Liquid → Gas (energy added)

Question 35

What is condensation?

Answer 35

Gas → Liquid (energy removed)

Question 36

What is sublimation?

Answer 36

Solid → Gas (energy added)

Question 37

What is deposition?

Answer 37

Gas → Solid (energy removed)

Question 38

Do changes of state occur at constant temperatures or changing temperatures?

Answer 38

At constant temperatures

Question 39

What is internal energy?

Answer 39

The total kinetic energy and potential energy of the particles.

Question 40

What is specific heat capacity?

Answer 40

The energy needed to raise the temperature of 1kg of a material by 1°C

Question 41

What is the formula for specific heat capacity?

Answer 41

SHC = change in energy/(mass*change in temperature)

Question 42

What is the unit for SHC?

Answer 42

J/kg°C

Question 43

How can you find the SHC of a metal?

Answer 43

Measure the mass of the metal with a mass balance Record the initial temperature of the metal. Wrap the metal in insulation Switch on the circuit that transfers energy to the block Heat the metal for 10 minutes Switch off the circuit and record the final temperature of the metal. Calculate the temperature difference Substitute the values into the SHC equation

Question 44

In an experiment, why is the measured value of specific heat capacity an overestimate?

Answer 44

Because we can counted the change in energy as the joules supplied to the metal, however the metal will lose some thermal energy to the surroundings over time

Question 45

What causes gas pressure?

Answer 45

Gas pressure is due to the rate of the collisions of the gas molecules with the sides of the container, which exert a force on it, and thus a pressure

Question 46

What happens to the pressure when we reduce the volume of a gas?

Answer 46

Reducing the volume increases pressure because particles collide more frequently with the container walls, exerting more force on a smaller surface area.

Question 47

Complete the sentence: As volume increases, pressure decreases. This means that they are...

Answer 47

Inversely proportionate

Question 48

Complete the sentence: As pressure increases, 1/volume increases. This means that they are...

Answer 48

Directly proportionate

Question 49

What does Boyle's Law state?

Answer 49

For a fixed mass of gas at a constant temperature, its pressure is inversely proportional to its volume

Question 50

What is the formula for Boyle's Law?

Answer 50

P1*V1 = P2*V2

Question 51

What assumptions are we making when using Boyle's Law?

Answer 51

That temperature is kept constant and the mass of gas is consistent

Question 52

At what temperature is there no kinetic energy of particles in any gas?

Answer 52

-273°C or 0 kelvin

Question 53

What is 1 kelvin equal to?

Answer 53

-272°C

Question 54

What is 10 kelvin equal to?

Answer 54

-262°C

Question 55

At what temperature in kelvin does water freeze?

Answer 55

273 kelvin

Question 56

At what temperature in kelvin does water boil?

Answer 56

373 kelvin

Question 57

How can you convert from degrees celsius to kelvin?

Answer 57

Add 273

Question 58

How can you convert from kelvin to degrees celsius ?

Answer 58

Subtract 273

Question 59

True or false: As long as pressure is in kelvin, the pressure of a gas is directly proportionate to the temperature, provided the volume and amount of gas are kept constant.

Answer 59

True

Question 60

What is the formula for pressure's law?

Answer 60

P1/T1 = P2/T2

Question 61

How can one Investigate the relationship between Pressure and Temperature for a fixed volume of gas?

Answer 61

Place dry air into a container of fixed volume Connect the container to a pressure gauge and place it into a water bath Heat the water bath using a bunsen burner Record the temperature of the gas using a thermometer and the pressure using the gauge Record other values of temperature and pressure