2024

• Complete the word equation: copper sulfate + sulfuric acid= 


  • copper sulfate + water
• Give one observation the student could make during step 4 which shows that the copper carbonate is in excess?


  • residue of copper carbonate at the bottom of the beaker
• Give one reason for filtering the mixture in step 5?


  • to remove excess copper
• Name the equipment that can be bused to warm the filtrate gently in step 6?

  • bunsen burner
• Calculate the mass of salt actually produced?


  • 92.8= mass/12.5 X 100
  • 0.928 X 12.5= mass=11.6
  • 11.6=mass
• Some salts can be produced by reacting sulfuric acid with a metal.

  Neither copper nor sodium is used to produce a salt with sulfuric acid.

  Give one reason why each metal is not used.

  • Copper- copper ha low reactivity so it will take a high amount of time to react
  • Sodium has a high reactivity so it will react aggressively with sulfuric acid which is hazardous
• Give one similarity and one difference between the electronic structures of sodium and potassium. 


  • similarity- Both have 1 electron in their outer shell
  • Difference- Sodium has 2 full shells but potassium has 3 full shells
• Give two observations made when potassium reacts with water?


  • lilac flame
  • potassium floats in water
• What is the colour of universal indication when added to potassium and what solution? 


  • blue/purple
  • potassium hydroxide has hydroxide (OH-) so it is an alkali
• 2.6


  • Chlorine and potassium bromide
• 2.7


  • Relative molecular mass increases and b.p increases
• 3.1


  Model A- Plum pudding model

  Model B- Nucler/Bohr model
• Compare plum pudding model with model of atom today


  • Plum pudding is a ball of positive charge with electrons scattered around whereas the atom today has a nucleus in the middle which contains positive charge
  • todays model has electrons in the shells which orbit the nucleus
• Define the term 'isotopes'


  • Same number of protons and electrons but different number of neutrons
• 4.2

  • at 0g it is 21 degrees cause that is the room temperature
  • between 0 and 0.8g it increases to 47 degrees as more zinc is reacting
• Explain why using a polystyrene cup gives more accurate results than using a glass beaker.


  • The polystyrene cup holds heat better causing the heat output of reaction to be more accurate
• 4.4


  • 2n2(aq) + Cu(s)
• 4.5


  -add them up and divide by 4
• Suggest one reason for the random errors in the experiment?


  • Copper sulfate intital temp may have been different
• Describe what happens to calcium atoms and chlorine atoms when the ionic compound calcium chloride is formed.

  • Calcium loses 2 electrons and give 1 to each chlorine atoms so they can all gain a full outer shell
  • resulting in Ca2+ and 2Cl-
  • forms Calcium chloride (caCl2) through electolysis?
• Solid calcium chloride cannot be electrolysed, give one reason why. 


  • Ions aren't able to flow and carry charge in a solid.
• Name the product formed at the negative electrode when aqueous calcium chloride solution is electrolysed. 


  • Hydrogen
• 5.4


  • option 1
• Copper chromate solution contains the ions Cu2+ and CrO42-, explain results shown in Figure 5. 


  • Copper is blue and chromate is yellow
  • copper is a positive ion so it will be attracted to the negative electrode
  • Chromate is a negative ion so it will be attracted to positive ion?
• Write the symbols of the five metals in Table 3 in order of reactivity.

  Justify your answer.

  • Most reactive: Mg, Zn, Ni, Cu, Ag
  • Justification: nickel is less reactive than Mg and Zn but more reactive then Cu and Ag
• 6.2

  1. Set Up: Use metal electrodes, sodium chloride solutions of different concentrations (e.g., 1.0, 0.5, 0.2 mol/dm³), and pure water as a reference.
  2. Experiment: Place electrodes in solutions, connect to a voltmeter, and stir gently. Measure and record the voltage for each concentration.
  3. Graph: Plot voltage (y-axis) against concentration (x-axis).
  4. Conclusion: Voltage increases with electrolyte concentration because more ions improve conductivity. Pure water shows no voltage due to the absence of ions.
• Describe how a hydrogen fuel cell produces a potential difference? 


  • hydrogen loses electrons and these are gained back when hydrogen reacts with oxygen to form water and these electrons carry charge which causes a potential difference
• Iron is a metal.

  Describe how iron conducts thermal energy. 


  • Iron is a transition metal which means it's delocalised electrons are able to carry thermal energy through the metal
• Pure iron is too soft for many uses

  Explain why mixing iron with other metals makes alloys which are harder then pure iron.


  • iron and other metals have different sized atoms which means that the other metal will distort irons layers which makes it harder for the layers it slide over each other
• 7.3


  • option 4
• 7.4


  • option 2
• 7.5 Calculate the percentage (%) by mass of iron in FE2O4

  RAM: o=16 Fe=56


  -56 x 3= 168

  -16 x 4= 64

  -168+64=232

  -168/232 x 100= 72.41
• 7.4


  mol=mass/mr

  9000
• 8.1- explain why propane has a low b.p


  • It has a simple molecular structure which means it has weak intermolecular forces that are easy to overcome
• 8.2


  • B
• What is meant by a weak acid? 


  -A weak acid is an acid that only partially ionises in solution
• Explain what happens to the pH of an acid as the acid is diluted with water.


  • the concentration on H+ ions decreases therefore neutralising the acid.