Waec Model Questions Vol1 2017 Biology Question 3

Practice practical question 3 from the 2017 Waec Model Questions Vol1 Biology examination. This question covers Nutrition .

Waec Model Questions Vol1 2017 Biology Practical
Topic: Nutrition
Question 3 WAEC_MODEL_QUESTIONS_VOL1 • 2017 • BIOLOGY • practical

A group of students carried out an experiment to determine the carbohydrate content of a commercial fruit‑juice sample using the dinitrosalicylic acid (DNS) method.

Question Parts

( a )
Describe the procedure for preparing a series of glucose standard solutions (0, 2, 4, 6 and 8 mg mL⁻¹) and for measuring their absorbance at 540 nm.
( b )
The absorbance readings obtained were: 0 mg mL⁻¹ – 0.012, 2 mg mL⁻¹ – 0.158, 4 mg mL⁻¹ – 0.301, 6 mg mL⁻¹ – 0.452, 8 mg mL⁻¹ – 0.603. State the equation of the best‑fit straight line and calculate the carbohydrate concentration in the diluted juice sample that gave an absorbance of 0.375.
( c )
The diluted juice sample was prepared by mixing 2.00 mL of the juice with 8.00 mL of distilled water. Using the concentration obtained in (b), calculate the percentage (w/v) of carbohydrate in the original undiluted juice. Show all steps, including the dilution factor.

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About This Question

This is Waec Model Questions Vol1 2017 Biology Question 3. It is one of the practical questions from the 2017 Waec Model Questions Vol1 Biology examination.

The question covers Nutrition .

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