Topic 6 - Molecules and Matter Flashcards

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1
Q

What equation links density, mass and volume?

A

Density (kg/m3) = mass (kg) / volume (m3) or p = m/v.

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2
Q

If a box has a mass of 56kg and a volume of 0.5 m3, what density does it have?

A

112 kg/m3

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3
Q

What is boiling point?

A

The temperature at which a liquid boils into a gas or condenses back into a liquid.

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4
Q

What is a freezing point?

A

The temperature at which a liquid freezes to become a solid.

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5
Q

What is internal energy?

A

The energy of particles in a substances due to their individual motion and positions.

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6
Q

What is latent heat?

A

The amount of energy need to change the state of 1kg of a substance without change their temperature.

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7
Q

What is melting point?

A

The temperature at which a pure substance melts or solidifies.

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8
Q

What is a physical change in a substance?

A

A change in which no new substances are produced but the appearance of an object may change.

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9
Q

What is the pressure of a substance?

A

The force applied per unit of cross-sectional area, measured in Pa (Pascals).

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10
Q

What is the specific latent heat of fusion?

A

The energy needed to melt 1 kg of a solid with no change in temperature.

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11
Q

What is the specific latent heat of vaporisation?

A

The energy needed to boil away 1 kg of a liquid with no change in temperature.

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12
Q

______ can be poured. What state of matter fits the sentence?

A

Liquids.

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13
Q

_____ particles are closely packed together and vibrate about fixed positions. What state of matter fits the sentence?

A

Solid.

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14
Q

_____ particles are very far apart and move around quickly, what state of matter fits best?

A

Gas.

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15
Q

What is the law of conservation of mass in changes of state?

A

The mass of the products is the same as the mass of the reactants.

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16
Q

What is internal energy the sum of?

A

Internal energy is the sum of all KE and PE (kinetic and potential energy).

17
Q

If particles are further apart they have more?

A

Potential energy.

18
Q

If particles are faster they have more?

A

Kinetic energy.

19
Q

What is a plateau?

A

A flat part of a graph.

20
Q

When heading steric acid from room temperature to above 50 degrees, why does the temperature stop increasing at 32 degrees for a minute and restart increasing again?

A

The energy is transferred to break the bonds in the steric acid and not to increase its temperature as it has reached its boiling point.

21
Q

What is the equation for specific latent heat?

A

Energy (J) = mass (kg) x specific latent heat (J/kg) or E = m x lf or lv. Lf is used with specific latent heat of fusion and lv is used in specific latent heat of vaporisation.

22
Q

What is absolute zero?

A

The coldest possible temperature in the universe.

23
Q

Why is absolute zero the lowest possible temperature in the universe?

A

It is the point where pressure reaches zero if you continue a graph relating pressure and temperature.

24
Q

What is the Kelvin scale?

A

The temperature scale that starts at absolute zero, where absolute zero is 0 degrees compared with -273.3 degrees Celsius.

25
Q

How do you convert from kelvin to Celsius?

A

By adding 273 to your Celsius value.

26
Q

What is Brownian motion?

A

The idea that particles move randomly, caused by other particles bouncing off of them.

27
Q

What is pascals?

A

The unit of pressure.

28
Q

What is Boyle’s law?

A

Pressure (Pa) x Volume (m3) = constant.

29
Q

What is the relationship between pressure and volume?

A

They are inversely proportional, so as pressure increases, volume decreases.

30
Q

What is the defintion for internal energy?

A

The sum of kinetic and potential energy of all particles in a system.

31
Q

What is sublimation?

A

Where a solid can directly turn into a gas.

32
Q

What kind of force is applied by a gas on walls of a container?

A

A force at right angles, which is called gas pressure.

33
Q

What is the result of carrying out work on a gas?

A

We transfer energy to gas particles, increasing the internal energy of the gas. This also increases temperature as kinetic energy of particles has increased.