O-LevelChemistryAcids, Bases & Salts5070/21 · Oct/Nov 2019 · Q610 Marks
Ethanoic acid, CH3COOH, is a weak acid.
- (a)What is the meaning of the term weak when applied to acids?[1]
- (b)Ethanoic acid is solid at 16.0°C. Describe the arrangement and movement of the particles in a solid. arrangement ............................................................................................................................ movement ................................................................................................................................ [2][2]
- (c)The melting point of ethanoic acid is 16.7°C. The boiling point of ethanoic acid is 118.0 °C. Deduce the physical state of ethanoic acid at 130.0°C. Explain your answer.[1]
- (d)The equation for the reaction of ethanoic acid with sodium carbonate is shown. 2CH3COOH + Na2CO3 → 2CH3COONa + CO2 + H2O A student added 3.18g of sodium carbonate to 224 cm³ of 0.250 mol/dm³ ethanoic acid. Show by calculation that sodium carbonate is in excess.[3]
- (e)Calcium reacts with ethanoic acid. The products are calcium ethanoate and hydrogen. Construct the equation for this reaction.[1]
- (f)Ethanoic acid reacts with butanol, C4H9OH, to produce an ester.
- (f)(i)Name the ester formed when ethanoic acid reacts with butanol.[1]
- (f)(ii)Draw the structure of this ester.[1]
Mark scheme
Marking points from the official mark scheme (Oct/Nov 2019). The mark or mark type is shown in brackets.
- 6(a) acid does not ionise completely / acid only partially dissociated / acid not fully dissociated
- 6(b) arrangement: regular / lattice (1)
- movement: (only) vibrating / not moving from place to place (1)
- 6(c) gas because 130 °C is above the boiling point
- 6(d) mol sodium carbonate = 3.18 / 106 OR 0.03 mol (1)
- mol ethanoic acid = 224 / 1000 × 0.250 OR 0.056 (1)
- sodium carbonate in excess because 0.03 × 2 = 0.06 OR sodium carbonate in excess because 0.056 ÷ 2 = 0.028 (1)
- 6(e) Ca + 2CH3COOH → (CH3COO)2Ca + H2
- 6(f)(i) butyl ethanoate
- 6(f)(ii) CH3COOC4H9
Write your answer and get it marked
On Oracle Prep you can write or photograph your own answer and have it marked by AI against this mark scheme, with feedback on what you missed.
Sign up free →