7/23/2019 Co-Ordinated Sciences Paper 6

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1 A bowl of crushed ice was taken out of a freezer, and left on a laboratory

bench to thaw. Its temperature was taken every 5 minutes for 1 hour. The

temperature of the laboratory was 2!".

The results are shown in the table below.

Time

(min) 5 1 15 2 25 # #5 $ $5 5 55 %

Temp

. (C)&1 &5 &1 2 ' 1$ 1( 1' 2 2

(a) )n the *raph paper provided, draw a line *raph to show these results.

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(b) -hat was the temperature inside the freezer//////////////////////////////////+1

(c) -hat was happenin* to the ice between 15 and 25 min after bein*

taken out of the freezer//////////////////////////////////+1

(d) -hy did the temperature not chan*e between these times//////////////////////////////////+1

(e) -as ice pure or did it contain impurities 0plain your answer.////////////////////////////////////

//////////////////////////////////...

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(f) -ould you epect the temperature of the water to continue risin*

above 2!" 0plain your answer.////////////////////////////////////

//////////////////////////////////...

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(g) A sample of benzene that had been cooled was put into a tube and

heated in a water bath. Its temperature was taken every 5 minutes for

an hour. The results are shown below.

Time

(min) 5 1 15 2 25 # #5 $ $5 5 55 %

Temp

. (C)5 5 5 1# 2( $5 % # ( ( ( ( (

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i. 3lot these results as a line *raph. +5

ii. -hat are the meltin* and boilin* points of benzene.

/////////////////////////////////

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2 The followin* shows the procedure of determinin* the meltin* point of a

solild.

4ou found

that in the rst

minute,

the temperature was 2(!" and the temperature increased steadily 1!" every

# seconds and then as it melted an hour later, it maintained a constant

temperature. The observed readin*s are recorded in the table on the net

pa*e6

1. 7et up the apparatus as shown in the *ure below.2. 8raw a results chart, so that you can ll in your

readin*s from instruction $.

3. 9eat the water until the solid melts.4. Take the tube, containin* the melted substance,out of the beaker of hot water. 3ut it into a clampon a retort stand. :ecord its temperature every#s. 8o this until the substance has completelysolidied.

5. 3lot a coolin* curve for the substance. 3ut time onthe horizontal ais, and temperature on thevertical ais.

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$

Time

;min< 5 1 15 # #5 $ $5 5 55 %

Temp

;!"