Category: Uncategorized

1.27 How many isomeric esters, including structural isomers and stereoisomers, can be made with the molecular formula C5H10O2, if methanoic acid is one of the two reactants used? (1)

1.30 In this question, all gases can be assumed to behave ideally. A chemist heats a mixture of nitrogen and oxygen gases in a sealed container at a constant temperature until the mixture reaches a dynamic equilibrium containing N2(g), O2(g) and NO(g). N2(g) + O2(g) 2NO(g) The chemist repeats the experiment at the same temperature using the same initial amounts of N2(g) and O2(g), but at a much higher pressure. Which statements about the second experiment at higher pressure are correct? (1)   1 At higher pressure, there are more particles per unit volume. 2 The composition of the equilibrium mixture does not change. 3 There are more collisions per second, so equilibrium is reached faster.  

1.26 How many of the following compounds produce a carboxylic acid on heating under reflux with an excess of hot acidified K2Cr2O7?   CH3CH2CHO CH3COCH3 CH3CH2CH2OH CH3CH(OH)CH3 (1)

 1.10 The equation for the reaction between carbon monoxide and hydrogen is shown. CO(g) + 3H2(g) CH4(g) + H2O(g) What are the units of Kp for this reaction? (1)     Right-click on the button to open the data booklet in a new tab.     

1.20 Which stage in the free radical substitution of ethane by chlorine has the lowest activation energy? (1)     Right-click on the button to open the data booklet in a new tab.    

 1.9 Dicarbon monoxide, C2O, is found in dust clouds in space. The structure of this molecule is C=C=O. The molecule contains no unpaired electrons. How many lone pairs of electrons are present in a molecule of C2O? (1)  

1.25 In which reaction is the organic compound oxidised? (1)   A CH3CH2CH2CHO + Tollens’ reagent B CH3CH2CH2CHO + LiAlH4 C CH3CH2CH2OH + concentrated H3PO4 D CH3CO2C2H5 + dilute H2SO4  

1.22 Chlorofluorocarbons damage the ozone layer by undergoing reactions with a free radical mechanism. The first stage of this is initiation. Which equation is most likely to be the initiation stage when chlorofluoromethane is involved in such a reaction? (1)     Right-click on the button to open the data booklet in a new tab.     

1.11 Why is the ionic radius of a chloride ion larger than the ionic radius of a sodium ion? (1)

 1.15 A piece of rock has a mass of 2.00 g. It contains calcium carbonate, but no other basic substances. It neutralises exactly 36.0 cm3 of 0.500 mol.dm–3 hydrochloric acid. What is the percentage of calcium carbonate in the 2.00 g piece of rock?   (1)