# 5 Solids, liquids and gasses

## 5.01 use the following units: degree Celsius (°C), Kelvin (K), joule (J), kilogram (kg), kilogram/metre3 (kg/m3), metre (m), metre2 (m2), metre3 (m3), metre/second (m/s), metre/second2 (m/s2), newton (N) and pascal (Pa)

The units for:

temperature: degree Celsius (°C) or Kelvin (K)

Energy: Joule (J)

mass: Kilogram (kg)

density: kilogram/metre cubed (kg/m3)

distance: metre (m)

area: metre squared (m2)

volume: metre cubed (m3)

velocity: metre per second (m/s)

acceleration: metre per second squared (m/s2)

force: newton (N)

pressure: pascal (Pa)

## 5.03 know and use the relationship between density, mass and volume: Units of density depend on units used for mass and volume:

E.g. mass in [g] and volume in [cm3] gives density in [g/cm3], however mass in [kg] and volume in [m3] gives density in [kg/m3].

## 5.04 practical: investigate density using direct measurements of mass and volume

• The density of an object can be found by measuring the mass and volume and applying the formula above to calculate the density.
• For a regular object use a ruler to measure the lengths needed to determine the volume.
• For an irregular object submerge it in water and measure the displaced volume.
• Measure the mass of either type of object using a measuring balance.

## 5.08 explain why heating a system will change the energy stored within the system and raise its temperature or produce changes of state   ## 5.10 describe the arrangement and motion of particles in solids, liquids and gases solids:

• Tightly packed
• Held in fixed pattern
• Vibrate about fixed positions

liquids:

• Tightly packed
• Can slide over each other

gasses:

• Very spread out
• Move with rapid, random motion

## 5.11 practical: obtain a temperature–time graph to show the constant temperature during a change of state 1. Remove the boiling tube of stearic acid from
the water bath
2. Place the tube into a beaker of room
temperature water
3. Add a separate thermometer to the water
4. Take readings from the thermometer in the
stearic acid and the water every minute
[Make sure to avoid parallax error while doing so]
5. Note readings in the table below
6. Note on the table when you observe the stearic
acid change from a liquid to a solid.
7. Plot your results in a graph

## 5.14 practical: investigate the specific heat capacity of materials including water and some solids

1. Set up the apparatus as shown the diagram.
2. Make note of all measurements: current (A), potential difference (V), mass (kg).
3. Use the electronic balance to measure the mass of your
4. Record the initial temperature of you block.
5. Switch on the heater and start your stopwatch.
[You will now leave the heater on for 10 minutes]
6. While the heater is switched on take readings from the
Ammeter and the Voltmeter.
7. Use these to calculate the Thermal Energy that will be
supplied to the block in 10 minutes
8. Record the temperature of your block after 10 minutes.
9. Calculate the Change in Temperature

## 5.16 understand why there is an absolute zero of temperature which is –273 °C

Absolute zero:

• At absolute zero the particles have no thermal energy or kinetic energy, so they cannot exert a force.
• Absolute zero = 0 Kelvin = -2730C ## 5.17 describe the Kelvin scale of temperature and be able to convert between the Kelvin and Celsius scales 0 K = -273 0C

E.g.         100K = -1730C

2000C = 473K

## 5.19 know that the Kelvin temperature of a gas is proportional to the average kinetic energy of its molecules The Kelvin temperature of a gas is proportional to the average kinetic energy of its molecules.

## 5.20 Explain, for a fixed amount of gas, the qualitative relationship between: pressure and volume at constant temperature, pressure and Kelvin temperature at constant volume.

• As you heat the gas, the kinetic energy of the particles increases, and thus so does their average speed.
• This means more collisions per second with the walls, and they exert a larger force on the wall.
• This causes in the total pressure being exerted by the particles to rise.
• If temperature is constant, the average speed of the particles is constant.
• If the same number of particles is placed in a container of smaller volume they will hit the walls of the container more often.
• More collisions per second means that the particles are exerting a larger force on the wall over the same time, so average force exerted on the walls has increased.

## 5.21 use the relationship between the pressure and Kelvin temperature of a fixed mass of gas at constant volume: P1/T1 = P2/T2

*Temperature must be in Kelvin

Temperature law:

For a fixed mass of gas at constant volume, the pressure is directly proportional to the Kelvin temperature

## 5.22 use the relationship between the pressure and volume of a fixed mass of gas at constant temperature:  P1V1 = P2V2

Boyle’s law:

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

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Section 1: Principles of chemistry

a) States of matter

b) Atoms

c) Atomic structure

d) Relative formula masses and molar volumes of gases

e) Chemical formulae and chemical equations

f) Ionic compounds

g) Covalent substances

h) Metallic crystals

i) Electrolysis

Section 2: Chemistry of the elements

a) The Periodic Table

b) Group 1 elements: lithium, sodium and potassium

c) Group 7 elements: chlorine, bromine and iodine

d) Oxygen and oxides

e) Hydrogen and water

f) Reactivity series

g) Tests for ions and gases

Section 3: Organic chemistry

a) Introduction

b) Alkanes

c) Alkenes

d) Ethanol

Section 4: Physical chemistry

a) Acids, alkalis and salts

b) Energetics

c) Rates of reaction

d) Equilibria

Section 5: Chemistry in industry

a) Extraction and uses of metals

b) Crude oil

c) Synthetic polymers

d) The industrial manufacture of chemicals