From Paper 1: Periodic table, elements and physical chemistry
11 mark
How many neutrons are in one ⁵⁶Fe³⁺ ion?
From Paper 1: Periodic table, elements and physical chemistry
21 mark
How many moles are in 4.00 g of NaOH?
From Paper 1: Periodic table, elements and physical chemistry
41 mark
What is the shape of an SF₆ molecule?
From Paper 1: Periodic table, elements and physical chemistry
51 mark
What is the oxidation number of chromium in Cr₂O₇²⁻?
From Paper 1: Periodic table, elements and physical chemistry
16(a)3 marks
25.0 cm³ of sodium carbonate solution needed 23.50 cm³ of 0.150 mol dm⁻³ hydrochloric acid for neutralisation.
Na₂CO₃ + 2HCl → 2NaCl + H₂O + CO₂
Calculate the concentration of the sodium carbonate solution.
From Paper 1: Periodic table, elements and physical chemistry
16(b)2 marks
Calculate the volume of CO₂, in cm³ at RTP, released when 0.500 g of CaCO₃ reacts completely with excess acid.
From Paper 1: Periodic table, elements and physical chemistry
16(c)3 marks
Calculate the atom economy for making CaO by heating CaCO₃, and suggest how the process could be made more sustainable.
From Paper 1: Periodic table, elements and physical chemistry
17(a)3 marks
Draw a dot-and-cross diagram for NH₃ and explain why its bond angle is 107°.
From Paper 1: Periodic table, elements and physical chemistry
17(b)4 marks
Explain why water has a higher boiling point than hydrogen sulfide, and why ice is less dense than liquid water.
From Paper 2: Synthesis and analytical techniques
19(a)5 marks
Compound P contains 62.1% C, 10.3% H and 27.6% O by mass. Its mass spectrum has M⁺ at m/z 58. Its IR spectrum has a strong absorption at 1715 cm⁻¹. It gives an orange precipitate with 2,4-DNP but no reaction with Tollens' reagent. Identify P.
From Paper 3: Unified chemistry
1(a)4 marks
1.325 g of anhydrous Na₂CO₃ (Mᵣ 106.0) was dissolved and made up to 250.0 cm³. 25.0 cm³ portions were titrated with hydrochloric acid; the mean titre was 24.10 cm³. Calculate the concentration of the acid.
From Paper 3: Unified chemistry
2(c)3 marks
The final volume of CO₂ was 80 cm³ at RTP. Calculate the concentration of the acid.
CaCO₃ + 2HCl → CaCl₂ + H₂O + CO₂
Figure 1
From Paper 3: Unified chemistry
3(b)5 marks
4.90 g of ammonium iron(II) sulfate, (NH₄)₂Fe(SO₄)₂·xH₂O, was dissolved and made up to 250 cm³. 25.0 cm³ portions needed 12.50 cm³ of 0.0200 mol dm⁻³ KMnO₄.
MnO₄⁻ + 8H⁺ + 5Fe²⁺ → Mn²⁺ + 5Fe³⁺ + 4H₂O
Determine x.
From Paper 3: Unified chemistry
7*6 marks
Explain the trend in boiling points of the halogens from fluorine to iodine, and the trend in boiling points of the hydrogen halides from HF to HI.
Score 0 / 42 · 0 of 14 marked
This paper is written by Plasmo in the style of the OCR A-Level Chemistry exam. It is not a past paper and is not produced or endorsed by the exam board.
Foundations in chemistry Exam Questions: OCR A-Level Chemistry | Plasmo