Homework 1
Signs of a Chemical Reaction
1. For each of the following, say whether a chemical reaction or a physical change is taking place.
a. Cutting your hair.
b. Mixing baking soda with vinegar to produce a gas.
c. Bending a piece of metal.
d. Crushing a painkiller into smaller pieces.
e. Copper turning green when it’s exposed to rain.
f. Mixing two clear liquids to form a yellow liquid.
g. Baking biscuits.
h. Burning wood.
i. Crumpling up a piece of paper.
j. Freezing water to make ice.
k. Food going off.
l. A candle burning.
m. A candle melting.
n. Your hair growing.
o. Breaking a windowpane.
(/15)
2. When magnesium (a chemical) reacts with acid, it fizzes and eventually disappears. The test tube
becomes hotter. Identify 3 signs that a chemical reaction has taken place
(/3)
3. On Zainab’s first day in S2 Science, her teacher demonstrated an experiment to the class. Here is
the report that Zainab wrote in her jotter:
From Zainab’s report, identify 2 signs that a chemical reaction has taken place.
(/2)
(Total /20)