A student claims that discovering the electron was enough evidence for the modern nuclear model of the atom.
Evaluate the claim using the development of atomic models.
[6 marks]OCR Gateway GCSE Combined Science June 2019 Paper 9
5 questions on this paper's topics
29:001 of 5
A beaker becomes colder when two substances react. A student sketches a reaction profile with products below reactants and no energy barrier.
Explain how the profile should be corrected and what each correction means.
[4 marks]Copper oxide is reduced by hydrogen: . A process must produce 12.8 g copper. : Cu = 64, O = 16, H = 1.
.1
Calculate the minimum mass of copper oxide needed if conversion is complete.
[4 marks].2
Calculate the mass of hydrogen that reacts with this copper oxide.
[2 marks]A student electrolyses concentrated aqueous potassium chloride using inert electrodes in a teacher-controlled demonstration with suitable ventilation. Potassium is more reactive than hydrogen.
.1
Predict the electrode products and explain the difference from molten potassium chloride.
[3 marks].2
Explain how charge is carried through the aqueous electrolyte and through the external metal wires.
[2 marks]In paper chromatography, dye A travels farther than dye B in the same time. Both start on the same line and the solvent front has passed both spots.
Explain the separation in terms of the mobile and stationary phases, and assess the suggestion that A must be a smaller molecule.
[4 marks]