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St Luke’s High School
Homework 4
Q1. Copy and complete the table below which shows a number of
possible chemical reactions.
Change
Observed
Is a new
substance
made?
Is there an
Is this a
energy change? chemical
reaction?
a. Bouncing a
ball
b. Grilling meat
c. Melting ice
cream
d. Chopping
wood
e. Burning wood
(5)
Q2.
Some orange ammonium dichromate crystals were placed on a heat
resistant mat and touched with a hot spatula. Immediately, a green
powder was thrown up into the air as if from a volcano. The centre of the
substance glowed red hot for about 20 seconds, after which all that was
left was the green powder.
Give three pieces of evidence which suggests that a chemical reaction has
taken place.
(3)