Csec Chemistry p2 June 2015

TEST CODE

FORM TP 2015055 CARIBBEAN

01212020 j

MAY/JUNE 2015

EXAMINATIONS

COUNCIL

CARIBBEAN SECONDARY EDUCATION CERTIFICATE® EXAMINATION CHEMISTRY Paper 02 - General Proficiency 2 hours and 30 minutes

READ THE FOLLOWING INSTRUCTIONS CAREFULLY. 1.

This paper consists of SIX questions in TWO sections. Answer ALL questions.

3.

Write your answers in the spaces provided in this booklet.

4.

DO NOT ,vrite in the margins.

S.

Where appropriate, ALL WORKING MUST BE SHOWN in this booklet.

6.

You may use a silent, non-programmable calculator to answer questions.

7.

If you need to rewrite any answer and there is not enough space to do so on the original page, you must use the extra lined page(s) provided at the back of this booklet. Remember to draw a line through your original answer.

8.

If you use the extra page(s) you MUST write the question number clearly in

the box provided at the top of the extra page(s) and, where relevant, include the question part beside the answer.

DO NOT TURN THIS PAGE UNTIL YOU ARE TOLD TO DO SO. Copyright~, 2013 Caribbean Examinations Council All rights reserved.

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SECTION A Answer ALL questions in this section. Write your responses in the spaces provided in this booklet. DO NOT spend more than 30 minutes on Question I.

1.

(a)

Hydrocarbons are widely used as fuels. They bum in oxygen to form carbon dioxide and water, and energy is released in the process. ( i)

List TWO natural sources of hydrocarbons.

(2 marks) (ii)

Name ONE hydrocarbon, other than wax, that can be used as fuel.

(1 mark) (b)

A student carried out an experiment in order to determine the heat of combustion of candle wax (a mixture of solirl hydrocarbons) by using the apparatus shown in Figure 1.

- - - Inverted can with hole in base

- ---- Candle L.-~~~~....,...l,--i.1.,-.,...I.~:::;:::;--- - Watch-glass

Figure 1. Apparatus for combustion of candle wax

GO ON TO THE NEXT PAGE 01212020/F 2015

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-3Procedure:

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1.

The conical flask was first weighed empty, then a known volume of water was added and it was reweighed.

2.

The conical flask was then clamped and encased by a can as shown in Figure 1.

3.

The initial temperature of the water in the flask was recorded.

4.

The candle and the watch-glass were weighed and placed directly under the calorimeter (the conical flask enclosed by the can).

5.

The candle was lit and the heat generated was used to heat the contents of the calorimeter.

6.

After 15 minutes, the candle was extinguished and the HIGHEST temperature of the \\·ater was recorded.

7.

The candle and watch-glass were allowed to cool and then reweighed.

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