3. A fixed mass of marble is reacted with dilute hydrochloric acid at a constant temperature. Explain why the rate of the reaction is increased if the lumps of marble are reduced in size.
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(2)
(Total 2 marks)
(c) Hydrogen peroxide decomposes more rapidly in the presence of aqueous hydrogen bromide. The decomposition proceeds as shown by the following equations.
H2O2 + HBr ® HBrO + H2O
HBrO + H2O2 ® H2O + O2 + HBr
(i) Write an equation for the overall reaction.
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(ii) Define the term catalyst.
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(iii) Give two reasons, other than an increase in the reaction rate, why these equations suggest that hydrogen bromide is behaving as a catalyst.
Reason 1 ............................................................................................................
Reason 2 ............................................................................................................
(5)
(Total 10 marks)
5. Gas G decomposes as shown in the equation below.
G(g) ® X(g) + Y(g)
(a) Draw, on the axes below, a Maxwell–Boltzmann distribution curve for a sample of G in which only a small proportion of molecules has energy greater than the activation energy, Ea.
(3)
(b) Define...
