Topic 3 Flashcards

1
Q

What are Properties of Solids?

A

Strong forces of Attraction
Particles don’t have much energy to vibrate
In fixed positions
A regular arrangement

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2
Q

What are Properties of Liquids?

A

Weaker forces of attraction
Moves in random directions
Have more energy than Solids
Can move past each other

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3
Q

What are the properties of Gases?

A
No forces of Attraction
Free to move 
Far apart
More energy than liquids & solids
Move in random directions and Speeds
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4
Q

What do colliding gas particles cause?

A

Pressure

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5
Q

What is Pressure?

A

It is the force exerted per unit.

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6
Q

So in a sealed container the outward gas pressure is what?

A

The total force exerted by all of the particles in a gas on a unit area of the container walls.

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7
Q

How can you increase pressure?

A

By increasing the number of collisions per second by increasing Temperature.

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8
Q

Decreasing the temperature of a gas decreases what and why?

A

When their is a lower temperature particles have lower Kinetic energy which means that their are fewer collisions per second, meaning their are fewer energy collisions, decreasing pressure.

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9
Q

Increasing the temperature of a gas increases what and why?

A

When their is a Higher temperature particles have Higher Kinetic energy which means that their are more collisions per second, meaning their are Higher energy collisions, this increases the pressure.

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10
Q

Nadia is investigating how the pressure of a gas is affected by its temperature. She places a balloon into a freezer for one hour.When she took it out of the freezer, she noticed that its volume had decreased. She then set it on a table. After a few minutes, it had returned to its original size, as shown below. Using ideas about particles and pressure, explain why the volume of the
balloon had decreased when it was taken out of the freezer.

A

The moment the balloon was placed into the freezer, the air inside it would have been at a higher temperature than the air inside the freezer
This would have caused thermal (heat) energy to flow from the air in
the balloon to the air in the freezer and the temperature of the air inside
the balloon would have decreased (until it had reached the operating
temperature of the freezer) [1].
This means that the kinetic energy of the air particles inside the balloon
would have decreased [1]. As the particles would then have been moving
more slowly, the amount of pressure they would exert on the inside
surface of the balloon would decrease (they would strike the inside
surface less frequently, and with less force each time they did so) [1].

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11
Q

What is Density?

A

Is a measure of the compactness of a substance which tells you the mass of a given volume.

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12
Q

What is the equation for Density?

A

Density(Kg/m 3)=Mass(Kg)/Volume(m 3)

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13
Q

What does density depend on?

A

What it is made of and how its particles are arranged.

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14
Q

What is a dense material?

A

has its particles packed tightly together.

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15
Q

Why are solids dense?

A

Because the particles are packed close together and solids have a lot of mass

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16
Q

Does a brick a high or low density and why?

A

The brick has a high density. It has lots of mass packed into his volume.

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17
Q

Does a Polystyrene block have a high or low density?

A

It has a low density. It has a lower mass packed into its volume.

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18
Q

Do gases have a low or high density?

A

Low density, the particles are far apart so gases only have a small mass for their volume

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19
Q

Polystyrene is a solid so why does it have a low density?

A

it has a very open structure and it is full of air spaces, it has a small mass for its volume.

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20
Q

What are regular objects?

A

they have dimensions which are easy to measure.

21
Q

What is an irregular objects?

A

With irregular objects, we cannot measure easily there dimensions.

22
Q

What is the required practical to measure density of a

regular solid object?

A

1) Use a balance to measure its mass
2) Use ruler to measure length, width and height
3) Times this together than use formula to find density.

23
Q

What is the required practical to measure density of a

irregular solid object?

A

1) Use a balance to measure its mass
2) Fill a Eureka can with water (a eureka can has a spout so water can flow out of can)
3) Place object into the water
4) This causes the water to be displaced and flow out the can through the spout.
5) Measure the volume displaced in a measuring cylinder. This volume is the same volume as the volume of the object.

24
Q

What is Internal Energy?

A

The total kinetic and Potential energy of all particles that make up a system.

25
Q

If we heat a solid what else increases?

A

The internal energy. At some point the solid can turn into a liquid.

26
Q

If we continue to heat a liquid what do we increase?

A

The internal energy . At some point the liquid will turn into a gas

27
Q

Heating causes what?

A

Particles gain energy in their kinetic stores and move faster, increasing the internal energy.

28
Q

When we cool down the gas what happens?

A

we reduce the internal energy. At some point the gas turns back into a liquid

29
Q

When we cool a liquid what do we do further?

A

We reduce the internal energy further, eventually the liquid turns into a solid.

30
Q

What is a solid to a liquid called?

A

Melting

31
Q

What is a liquid to a gas called?

A

Evaporating

32
Q

What is a gas to a liquid called?

A

Condensation

33
Q

What is a liquid to a solid called?

A

Freezing

34
Q

What is a solid to a gas called?

A

Sublimating

35
Q

Is a change of state a Physical or chemical change and why?

A

Physical as you don’t end up with a new substance.

36
Q

What does it mean to say mass is conserved when a substance changes state?

A

The number of particles doesn’t change, none of it is lost when the substance changes state

37
Q

What is a change of state?

A

It occurs when a substance is heated enough, the particles will have enough energy in their kinetic energy stores to break their bonds holding them together.

38
Q

During an experiment a solid is heated until it melts into a liquid. Explain how heating the solid causes this change in state.

A

Heating the solid transfers energy to the kinetic energy stores of the particles, increasing the internal energy. When the particles have enough energy in their kinetic stores, they break bonds holding them together. The solid changes state and becomes a liquid.

39
Q

An ice cube is placed into a glass of water which is at room temperature.
After 15 minutes, the ice has melted completely.
Using the particle model, explain fully what happens to the ice as it melts

A

• The particles in a solid are packed tightly, and vibrate about fixed
positions [1]
• When the ice cube (which is at a lower temperature) is placed into the
water (which is at a higher temperature), there is a net flow of heat
energy from the water to the ice [1]
• This increases the internal energy stored by/temperature of the ice
• As its temperature increases, the particles within the ice vibrate more
rapidly (about their fixed positions) [1]
• When these particles have enough energy, the bonds holding them
together will be broken, and they will be able to move freely/flow
around one another [1]

40
Q

How do you find density of a Liquid?

A

1) Place a measuring cylinder on a balance and zero the balance
2) Pour 10 ml of the liquid into the measuring cylinder and record the liquids mass
3) Pour another 10 ml into the measuring cylinder, repeating the process until the cylinder is full and recording the total volume and mass each time.
4) For each measurement use the formula to find the density. (l ml = 1 cm cubed)
5) Finally take an average of your calculated densities. This will give you a value for the density of the liquid.

41
Q

On a Graph of melting and freezing what happens when a line is flat?

A

Increasing the internal energy to break the bonds, and it is changing state.

42
Q

In a Freezing and condensing graph what happens when line is flat?

A

Bonds are forming, so energy is released and internal energy decreases

43
Q

What is Latent heat?

A

The energy needed to change the state of a substance.

44
Q

What is Specific latent heat?

A

It is the amount of energy needed to change 1 kg of a substance without changing temperature.

45
Q

The specific latent heat for changing between a solid and liquid ( melting or freezing) is called what?

A

Specific latent heat of fusion

46
Q

The specific latent heat for changing between a liquid and gas ( evaporating boiling or condenstion) is called what?

A

Specific latent heat of vaporization.

47
Q

What is the formula for Specific latent heat?

A

E = M X L
E= energy in joules
M = mass in Kg
L is specific latent heat in J/kg

48
Q

The specific latent heat of vaporization for water is 2260000 J/kg. How much energy is needed to competely boil 1.50 kg of water at 100’C?

A

E = M L
1.5 X 2260000
= 3,390000 J