A) Potassium reacts with water to form potassium hydroxide.
B) Sugar dissolves in water.
C) Sugar is a solid at room temperature.
D) Gasoline and water do not mix.
45) Which of these is a chemical change?
A) The hair stylist cuts your hair.
B) Bleaching powder dissolves in water.
C) Silkworms convert mulberry leaves into silk.
D) Wool is spun into yarn.
46) Which of these does NOT involve a chemical change?
A) Cocaine causes the release of norepinephrine from nerve cells.
B) Red delicious apples taste sweet.
C) Antacids often help an upset stomach.
D) Mercury is used in barometers because it has a high density.
47) A mixture of iron, salt and sand can be separated using a magnet, water, a filter and a hot plate.
Think about this separation. The separation of this mixture
A) uses only physical changes or processes.
B) uses only chemical changes or processes.
C) uses both chemical and physical changes or processes.
D) cannot be done with the materials listed.