Heating meths

Heating meths

Pencil and paper
Overview
Using this Resource
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Marking Student Responses
Further Resources
This task is about what happens with particles when heating methylated spirits.

Methylated spirits (meths) is almost pure ethanol. Lana wanted to find its boiling point.

  1. She weighed 20 mL of meths into a small boiling tube and heated this in a waterbath.
  2. She recorded the temperature and observed the meths every minute. The temperature inside the laboratory that day was 18°C.
  3. After 4 minutes the meths started to boil. The temperature of the meths was then 78°C.
  4. After 7 minutes all the meths had evaporated from the boiling tube.
 
a)    Draw and label a graph of temperature versus time for Lisa's investigation.
 
 
 
 
b)
Explain, in terms of particles, what is happening during the sloping section of the graph.
 
 
 
 
 
c)
Explain what happens to the particles in the flat section of the graph.
 
 
 
 
Task administration: 
This task can be completed with pencil and paper.
Level:
5
Curriculum info: 
Science, Communicating in science, Material World
Keywords: 
changes, particle nature of matter, boiling point, heating curve, liquid, gas, graph construction, graph interpretation
Description of task: 
Students draw a graph from some information they are given about the heating of meths in a water bath. Students then explain in terms of particles what is happening for the sloping section and the flat section of the graph.
Curriculum Links: 
Science capabilities
The capabilities focus is brought about by the conversations you have and the questions you ask.
 
Capability: Interpret representations
This resource provides opportunities to discuss:
  1. the importance of labelling the axes of graphs to enable the graph to be interpreted
  2. interpreting a graph using their developing science understanding of the particle theory.
Science capabilities: 
Interpret representations
Answers/responses: 
  

Y9 (11/1996)

a)		   (See graph below)
Title, even spacing on axes.
Labelled axes (with units)
Points plotted correctly (± 2°C)
difficult
difficult
difficult
b) i)

ii)

 Liquid is heating up, that is, particles are moving
faster or further apart.
Liquid is changing into a gas, that is, particles are now moving fast enough to move into the gas phase or the forces between particles break down.		 difficult

very difficult

Heating Curve for Meths