(c) Change 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

5.12 know that specific heat capacity is the energy required to change the temperature of an object by one degree Celsius per kilogram of mass (J/kg °C)

Specific heat capacity:

  • Amount of heat energy required to increase the temperature of 1kg of a substance by 10
  • Unit J/kg 0C

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
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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

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