Practical Questions

Question 1

Required practical 2 - Enthalpy change (CuSO4)

Answer 1

1.) weigh between 3.9-4.10 g of anhydrous copper(II)sulfate in a dry weighing boat. Record precise mass.
2.) construct a suitable table to record results for intervals of 1 minute up to 15 minutes
3.)using a measuring cylinder add 25cm cubed of distilled water to a polystyrene cup and record initial temp. Start the timer and read temperature for every minute for 3 minutes.
4.)at the 4th minute add powdered anhydrous copper sulfate to the polystyrene cup. DO NOT RECORD TEMP AT T=4. At the 5th minute continue measuring the temperature in minute intervals until the 15th minute.
5.) Plot a graph of temp (y-axis) against time( x-axis) draw two separate lines of best fit. One line of best fit joins the points before addition of copper sulfate and another joins the points after the addition of copper sulfate.
Use the graph to determine temperature change at the time of 4 minutes which = 🔼t
Q=MC🔼t

Question 2

How do you test for purity of a sample ?

Answer 2

• determine the range of temperature it melts over
• if the sample is pure it will melt at a sharp(small) range of values

In depth answers :