Freezing and melting points

Freezing and melting points

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This task is about freezing and melting points of some liquids.

Question

Not everything will freeze when left in a freezer! The temperature inside a freezer is ¯4°C. 
Below is a table of the melting points for three substances which are all liquids at room temperature.
 
Substance Melting point (°C)
methylated spirits (meths)
(mostly ethanol)
 ¯114
petrol (mostly octane)
 ¯56.8
ethanoic acid

(used to make vinegar)

  16.7
 
Three 500 mL bottles are each half-filled with the liquids and were placed in a freezer overnight.
 
a)   Which liquid(s) would be frozen the next day? 

    • Methylated spirits

    • Petrol

    • Ethanoic acid

Question 1Change answer

b) Explain, in terms of particles, what has happened when a liquid has frozen.

Question 1Change answer

c)   Will the level in the frozen bottle(s) be higher or lower than before?
HigherLower
Explain your answer in terms of the particles.
Level:
5
Curriculum info: 
Science, Knowledge, Material World
Keywords: 
changes, particle nature of matter, solid, liquid, changes of state, table interpretation
Description of task: 
Using provided data students decide which of three liquids would freeze if placed in a freezer. Students explain what happens to particles when they freeze and how the level changes due to freezing.
Answers/responses: 
  

Y9 (08/1997)

Y10 (08/1997)
a)   Ethanoic acid. easy easy
b)   The particles get closer together/
slow down.		 very difficult difficult
c) i)
ii)		 Lower.
The particles in a solid are closer together than those in a liquid so the solid takes up less space (water is the exception, not the rule).		 very difficult difficult