0 cm3 of the vitamin C tablet solution from Step 1 was added to the conical
flask from Step 2 to react with the iodine produced, as shown in the equation.
C H O (aq) + I (aq) → C H O (aq) + 2HI(aq)
Question
Mathematics
Edexcel2024
10
Question
Mathematics
Edexcel2024
10
Question
Mathematics
Edexcel2024
2 3
(3)
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(e) The relevant equilibria that maintain the pH of blood are shown.
Equilibrium 1 CO (aq) + H O(l) H CO (aq)
Question
Mathematics
Edexcel2024
3 3
(i) When a person exercises vigorously the concentration of carbon dioxide (aq)
in the blood increases.
Explain how this increase in the concentration of carbon dioxide affects the
pH of the blood.
Refer to the equilibria in your answer. No calculation is required.
(2)
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(ii) Explain how the carbonic acid–hydrogencarbonate buffer system in
Equilibrium 2 acts to restore the pH of the blood after a person has exercised.
(2)
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(Total for Question 4 = 14 marks)
Question
Mathematics
Edexcel2024
Question
Mathematics
Edexcel2024
Vitamin C has the molecular formula C H O .
Question
Mathematics
Edexcel2023
7
agent made the statement shown.
‘Standard electrode potential data shows that it is never feasible
for a 1.00 mol dm–3 solution of potassium dichromate(VI) to oxidise
the chloride ions in hydrochloric acid.’
Comment on this statement using the data and equilibria shown.
Equilibrium 1
Cr O2–(aq) + 14H+(aq) + 6e– 2Cr3+(aq) + 7H O(l) Ed = +1.33 V
Question
Chemistry
CAIE2023
The Haber process produces ammonia by the reversible reaction:
N₂(g) + 3H₂(g) ⇌ 2NH₃(g) ΔH = −92 kJ mol⁻¹
(a) State Le Chatelier's principle.
(b) Predict and explain the effect on the equilibrium yield of ammonia if:
(i) the pressure is increased
(ii) the temperature is increased
(c) Explain why a catalyst is used in the Haber process even though it does not change the equilibrium yield.