Cambridge International Examinations: Combined Science 0653/32 March 2017
Cambridge International Examinations: Combined Science 0653/32 March 2017
Cambridge International Examinations: Combined Science 0653/32 March 2017
Published
This mark scheme is published as an aid to teachers and candidates, to indicate the requirements of the
examination. It shows the basis on which Examiners were instructed to award marks. It does not indicate the
details of the discussions that took place at an Examiners meeting before marking began, which would have
considered the acceptability of alternative answers.
Mark schemes should be read in conjunction with the question paper and the Principal Examiner Report for
Teachers.
Cambridge will not enter into discussions about these mark schemes.
Cambridge is publishing the mark schemes for the March 2017 series for most Cambridge IGCSE,
Cambridge International A and AS Level components and some Cambridge O Level components.
1(d)(i) bacteria; 2
feed on / breakdown sugar ;
produce acid ;
2(a)(ii) exothermic ; 1
2(b)(ii) (change) temperature / (use a) catalyst (change) surface area / particle size / stirring; 1
3(c) 1
speed
time ;
4(a)(i) 2; 1
4(a)(ii) 1,3,5 ; 1
4(a)(iii) eating ; 1
5(a)(i) coal ; 1
5(a)(ii) methane ; 1
5(a)(iii) oxygen ; 1
allow O2 ignore O
5(c)(ii) 2
;;
6(c)(i) evaporation ; 1
8(a)(i) floats ; 1
8(a)(ii) 2
sodium LHS (either order) ;
sodium + water + hydrogen
hydroxide RHS (either order) ;
8(a)(iii) sinks ; 2
no reaction ;
either order
8(b)(ii) unreactive ; 1