CHAPTER 6 : NUTRITION

1 An experiment was carried out to determine and compare the energy content in white bread and peanuts.The mass of each food sample used was 5g.The volume of distilled water used was 20 ml.The density of water is 1 gm/-1.

Figure 1 shows the set-up of the apparatus used in the experiment

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Figure 2 shows the initial water temperature for each food sample.

Table 1 shows the highest water temperature after each food sample is completely burnt.

(a) (i) Record the initial water temperature in the space provided in Figure 2.

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(ii) Record the final water temperature in the boxes provided in Table 1. [3 marks]

(b) (i) State two different observations made from Table 1.1 ………………………………………………………………………………………………………

2 ……………………………………………………………………………………………………… [3 marks]

(ii) State two inferences from the observations in (b)(i).1 ………………………………………………………………………………………………………

2 ……………………………………………………………………………………………………… [3 marks]

(c) Complete Table 2 based on the experiment that was carried out.

Variables Particulars to be implemented

Manipulated variable…………………………………………………….…………………………………………………….

How to alter the manipulated variable…………………………………………………….…………………………………………………….

Responding variable…………………………………………………………………………………………………………

How to determine the responding variable…………………………………………………….…………………………………………………….

Controlled variable…………………………………………………………………………………………………………

How to maintain the controlled variable…………………………………………………….…………………………………………………….

TABLE 2[6 marks]

(d) State the hypothesis for this experiment. …………………………………………………………………………………………………………..

[3 marks]

(e) (i) Construct a table to record the results of this experiment. Your table should contain the following titles: ∙ Food sample ∙ Increase in water temperature ∙ Energy value

Specific heat capacity of water is 4.2 Jg-1C˚ -1

Use the formula:Energy value = Mass of water x specific heat capacity of water x temperature increase Mass of food

[3 marks](ii) Based on the table in (e)(i), state the relationship between the food class and the energy value of each food sample. ……………………………………………………………………………………………………. …………………………………………………………………………………………………….. [3 marks]

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(f) Based on the result of the experiment, what can you deduce about the energy value? …………………………………………………………………………………………………… …………………………………………………………………………………………………… …………………………………………………………………………………………………… …………………………………………………………………………………………………… [3 marks]

(g) This experiment was repeated using a cashew nut. Predict the observation and the energy value that will be obtained. …………………………………………………………………………………………………. ………………………………………………………………………………………………….. ………………………………………………………………………………………………….. [3 marks]

(h) The picture shows various types of food samples: Margarine, rice, palm oil, boiled potato, cashew nut and maize. Classify the food samples into two food classes in Table 3, based on the energy value that is equivalent to that of white bread or peanut.

Food samples with equivalent energy value as

white bread peanut

TABLE 3[3 marks]

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2007

1. An experiment was carried out to investigate the effect of light intensity on the rate of photosynthesis of a Hydrilla sp. sprig

The following steps were carried out..

Step 1 : 50 ml of 2% sodium hydrogen carbonate solution was placed in a boiling tube.

Step 2 : A Hydrilla sp. sprig was immersed in the sodium hydrogen carbonate solution.

Step 3 : A light source from a 60W bulb was placed at a distance of 60cm from the boiling tube.

Diagram I shows the apparatus set-up used in this experiment.

(a) In Table 1, list all the materials and apparatus labelled in Diagram 1.Materials Apparatus

Table 1 (3 marks)Table 2 shows the results of this experiment.

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(b) Record the total number of bubbles released in 5 minutes in the boxes providedin Table 2.

[3 marks](c) (i) State two different observations made from Table 2.

Observation 1 :

………………………………………………………………………………………………………………

Observation 2 :

……………………………………………………………………………………………………………..

(ii) State the inference which corresponds to the observations in 1(c)(i). Inference from observation 1 :

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………………………………………………………………………………………………………….Inference from observation 2 :

…………………………………………………………………………………………………………..[3 marks]

(d) Complete Table 3 based on this experiment.

VariableMethod to handle the variable

Manipulated variable

Responding variable

Constant variable

Table 3 (3 marks)(e) State the hypothesis for this experiment.

………………………………………………………………………………………………………………..

……………………………………………………………………………………………………………….

(f) (i) Construct a table and record all the data collected in this experiment.

Your table should have the following titles:

- Distance between light source and Hydrilla sp.

- Total number of bubbles released in 5 minutes

- Light intensity

Use the formula:

1Distance between light source and Hydrilla sp.

(f) (ii) Use the graph paper provided to answer this part of the question.

Using the data in 1(f)(i), draw the graph of the total number of bubblesagainst the light intensity. [3

marks]

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Light intensity =

(g) Based on the graph in 1(f)(ii), explain the relationship between the total number of bubbles and the light intensity.

…………………………………………………………………………………………………………….

…………………………………………………………………………………………………………….

[3 marks]

(h) This experiment is repeated using two sprigs of Hydrilla sp.Predict the total number of bubbles released in 5 minutes by these two sprigs of Hydrilla sp.Explain your prediction

…………………………………………………………………………………………………………

…………………………………………………………………………………………………………[3 marks]

(i) Based on the result from this experiment, what can be deduced about photosynthesis?

……………………………………………………………………………………………………………

…………………………………………………………………………………………………………… [3 marks]

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