CHAPTER 6: States of matter
Worksheet 6.1
Changing the boiling
point of water
Science Quest 8: pages 222–3
Answers
You will need:
water
Bunsen burner
safety glasses
2  250 mL beakers
heatproof mat
thermometer
salt
matches
Temperatur
e (C)
Time (min)
●
●
●
●
●
●
retort stand
sugar
tripod
bosshead and clamp
0
1
2
3
vinegar
gauze mat
teaspoon
100 mL measuring cylinder
4
5
6
7
8
9
10
Tap water
Salt water
Sugar water
Vinegar water
Set up the equipment as shown in worksheet 1.6. Put on your safety glasses.
Measure 100 mL of water with the measuring cylinder and pour it into the beaker.
Measure the starting temperature of the water (time  0 min).
Light the Bunsen burner and place it under the beaker. Measure the temperature of the water
every minute for 10 minutes. Record your observations in the table above.
After 10 minutes, turn off the Bunsen burner and allow the equipment to cool.
Repeat the above steps with 100 mL of water with two teaspoons of salt stirred in, then 100 mL of
water with two teaspoons of sugar stirred in, and lastly with 80 mL of water with 20 mL of vinegar
stirred in.
1. Draw a line graph of your results. Use a
different coloured line for each water
mixture. Plot time on the horizontal axis
The temperature of the water remains
constant at 100°C even though it is still
being heated. The graph now has a
horizontal line with temperature = 100°C
4. What effect does adding substances to the
water have on its boiling point?
The boiling point of the solution increases
when salt is added.
5. What would happen to the temperature of
each water sample if you continued to heat
it past the 10-minute mark?
The temperature of each water sample
would remain constant at the boiling point
of each sample.
Conclusion
and temperature on the vertical axis.
Answers will vary. An example graph is
shown.
2. How can you tell when the water has
reached its boiling point?
The liquid begins to bubble strongly.
3. Is there any part of the graph that shows the
liquid has reached its boiling point?
© John Wiley & Sons Australia, Ltd
When a sample of water is heated constantly,
the temperature increases at a steady reate.
When the temperature reaches the boiling
point of 100°C, the temperature stays constant
and the water boils.
Adding substances to water increases the
boiling point.
Science Quest 8 Student Workbook