Neco Model Questions Vol1 2019 Biology Question 3

Practice practical question 3 from the 2019 Neco Model Questions Vol1 Biology examination. This question covers Nutrition .

Neco Model Questions Vol1 2019 Biology Practical

Topic: Nutrition

Question 3 NECO_MODEL_QUESTIONS_VOL1 • 2019 • BIOLOGY • practical

A group of students carried out an experiment to determine the carbohydrate content of an unknown food sample using the Benedict’s test. They prepared a series of glucose standards and recorded the absorbance at 620 nm as follows: Standard (g/100 mL) : 0.2 0.4 0.6 0.8 1.0 Absorbance (A) : 0.12 0.24 0.36 0.48 0.60 The unknown solution (prepared by dissolving the extracted food in water) gave an absorbance of 0.42. The students extracted 2.5 g of the food in 25 mL of distilled water before the test. Answer the following questions:

Question Parts

( a )

Construct the calibration curve by determining the linear relationship between absorbance (A) and carbohydrate concentration (C) in g/100 mL.

( b )

Using the equation obtained in (a), calculate the carbohydrate concentration of the unknown solution (in g/100 mL).

( c )

Determine the percentage of carbohydrate in the original food sample.

( d )

Identify two possible sources of error in this experiment and suggest a way to minimise each.

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About This Question

This is Neco Model Questions Vol1 2019 Biology Question 3. It is one of the practical questions from the 2019 Neco Model Questions Vol1 Biology examination.

The question covers Nutrition .

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