11.7. Carboxylic acids
A subsection of Chemistry, 0620, through 11. Organic chemistry
Listing 10 of 101 questions
The structure of crotonicacid is shown. C H C C H H O O H H C H On the structure, draw a circle around the functional group which shows that this is an unsaturated compound. Deduce the formula of crotonicacid to show the number of carbon, hydrogen and oxygen atoms. Complete the table to calculate the relative molecular mass of crotonicacid. Use your Periodic Table to help you. type of atom number of atoms relative atomic mass carbon 4 × 12 = 48 hydrogen oxygen  relative molecular mass = Acids react with bases such as calciumoxide. Complete the word equation for the reaction of nitricacid with calciumoxide. nitric acid + calcium oxide +  Calciumoxide is manufactured from limestone by thermal decomposition. Give the name of the main chemical compound in limestone. State the meaning of the term thermal decomposition. Calciumoxide reacts with water to produce slaked lime. State one use of slaked lime. 
0620_w20_qp_33
THEORY
2020
Paper 3, Variant 3
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This question is about alcohols, carboxylic acids and esters. Ethanol will react with hot aqueous potassiummanganate(to form ethanoicacid. State the other condition needed for this reaction to take place. State the type of chemical change that happens to the ethanol during this reaction. The structure of ethanoic acid is shown. O O H C H H C H Complete the dot-and-cross diagram to show the electron arrangement in a molecule of ethanoicacid. C C O H H H H O  Ethanoicacid is a weak acid and hydrochloricacid is a strong acid. Complete the table to show the similarities and differences in the properties of samples of these two acids of equal concentration. dilute ethanoic acid dilute hydrochloric acid extent of dissociation colour after adding universal indicator solution observation when magnesium ribbon is added  Ethanoicacid will react with an alcohol to form the ester shown. H C H H C C C O O C H H H H H H H Name the other product formed when ethanoicacid reacts with an alcohol to make this ester. Give one condition needed when ethanoic acid reacts with the alcohol to make this ester. Draw the structure of the alcohol which was added to ethanoicacid to make this ester. Show all of the atoms and all of the bonds.  Polyesters can be manufactured from carboxylic acids and alcohols. Hexanedioic acid has the structure: HOOC–CH2–CH2–CH2–CH2–COOH. This structure can be simplified as shown. C O C O O H O H Ethanediol has the structure: HO–CH2–CH2–OH. This structure can be simplified as shown. O H O H The functional groups are found at the end of each molecule. State what is meant by the term functional group. Determine the empirical formula of hexanedioicacid. Calculate the percentage by mass of oxygen present in ethanediol. Give your answer to the nearest whole number.  % Complete the diagram to show a section of polyester manufactured from hexanedioicacid and ethanediol. Include all of the atoms and all of the bonds in the linkages.  State the name of a polyester. 
0620_w20_qp_42
THEORY
2020
Paper 4, Variant 2
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Questions Discovered
101