Classify each of the following changes as physical or chemical. Give reasons for your answers.
a) When molasses is warmed, it becomes less viscous
b) When a chair is painted, it has a new color.
c) When sugar is stirred into hot water, it dissolves.
d) When egg whites are cooked, they become opaque.
e) When wood is sawed, some of it changes to sawdust.
f) When wood is burned, ashes remain.
g) When vinegar is added to baking soda, bubbles are seen.