11.7. Carboxylic acids
A subsection of Chemistry, 0620, through 11. Organic chemistry
Listing 10 of 101 questions
This question is about acids and carbonates. Describe the colour change when excess acid is added to a solution of methyl orange in alkaline solution. from to ���������������������������������������������������������������� Complete the word equation for the reaction of hydrochloricacid with calcium carbonate. hydrochloric acid + calcium carbonate + + water  Calcium carbonate decomposes when heated. calcium carbonate → calcium oxide + carbon dioxide Calcium carbonate is used in the manufacture of lime (calcium oxide). State one other use of calcium carbonate. The decomposition of calcium carbonate is endothermic. State the meaning of the term endothermic. The energy level diagram for the decomposition of calcium carbonate is shown. energy progress of reaction CaCO3 CaO + CO2 Explain how the energy level diagram shows that this reaction is endothermic. When 0.50 g of calciumcarbonate decomposes, 120 cm3 of carbondioxide gas is produced. Calculate the volume of carbondioxide gas produced when 0.10 g of calciumcarbonate is used.  volume of carbon dioxide gas = cm3 
0620_s22_qp_33
THEORY
2022
Paper 3, Variant 3
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Ethanoicacid is manufactured by the reaction of methanol with carbonmonoxide. An equilibrium mixture is produced. CH3OH+ COCH3COOHState two characteristics of an equilibrium.  The purpose of the industrial process is to produce a high yield of ethanoicacid at a high rate of reaction. The manufacture is carried out at a temperature of 300 °C. The forward reaction is exothermic. Use this information to state why the manufacture is not carried out at temperatures: ● below 300 °C ● above 300 °C.  Complete the table using only the words increases, decreases or no change. effect on the rate of the forward reaction effect on the equilibrium yield of CH3COOHadding a catalyst no change decreasing the pressure  Suggest which of the following metals is a suitable catalyst for the reaction. Give a reason for your answer. aluminium calcium cobalt magnesium potassium suitable catalyst reason  Ethanoicacid is a member of the homologous series of carboxylic acids. State the general formula of this homologous series. Draw the structure of the carboxylic acid containing three carbon atoms. Show all of the atoms and all of the bonds.  When carboxylic acids react with alcohols, esters are produced. The formula of ester X is CH3CH2CH2COOCH3. Name ester X. Give the name of the carboxylic acid and the alcohol that react together to produce esterX. carboxylic acid alcohol  Ester Y has the following composition by mass: C, 48.65%; H, 8.11%; O, 43.24%. Calculate the empirical formula of ester Y.  empirical formula = Ester Z has the empirical formula C2H4O and a relative molecular mass of 88. Determine the molecular formula of ester Z.  molecular formula = 
0620_s22_qp_41
THEORY
2022
Paper 4, Variant 1
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Fig.7.1 shows the displayed formula of mesaconicacid. C C C H O H C O H C O H H H O On Fig.7.1 draw a circle around one carboxylic acid functional group. Deduce the molecular formula of mesaconicacid. Mesaconicacid is a colourless compound. Describe the colour change when excess mesaconicacid is added to aqueous bromine. from to ������������������������������������������������������������� Ethanoicacid belongs to the homologous series of carboxylic acids. Define the term homologous series. Complete the word equation for the reaction of ethanoicacid with magnesium. ethanoic acid + magnesium +  Ethanoicacid reacts with ethanol. The organic product has the molecular formula C4H8O2. Complete Table7.1 to calculate the relative molecular mass of C4H8O2. Table 7.1 atom number of atoms relative atomic mass carbon 4 × 12 = 48 hydrogen oxygen  relative molecular mass = Ethanol can be manufactured by fermentation. Complete the word equation for one other method of manufacturing ethanol. + → ethanol 
0620_s23_qp_31
THEORY
2023
Paper 3, Variant 1
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