Question 2A
You are provided with a beaker, a thermometer, a stirrer, a measuring cylinder, a bunsen burner, a wire gauze, a 50 g mass, a pair of tongs, water, tripod stand and other necessary materials.
i. Using the measuring cylinder, measure 150 cm3 of water into the beaker.
ii. Record the volume v of the water in the beaker.
iii. Calculate the mass m of the water, given that m = ρv and; ρ = 1 g cm3.
iv. Measure and record the initial temperature Ө0 of the water in the beaker.
v. Hold the 50 g mass with the pair of tongs in the flame of the bunsen burner for 2 minutes
vi. Quickly transfer the 50 g mass to the water in the beaker.
vii. Stir gently and record the highest temperature Ө1 attained.
viii. Evaluate Ө = (Ө1 - Ө0).
ix. Empty the content of the beaker and repeat the procedure above for other values of v = 200 cm3, 250 cm3, 300 cm3 and 350 cm3.
x. Tabulate your reading
xi. Plot a graph with m on the vertical axis and Ө on the horizontal axis.
xii. Evaluate k = 50/s
xiii. State two precautions taken to obtain accurate results.
Observation
Part (a) Majority of the candidates avoided this question. The few candidates that attempted the question performed on an average. Many candidates failed to state the unit of the volume of water obtained from the measuring cylinder and the unit of temperature. Also, many schools did not set up the experiment for the candidates.