Some students observe four different lab investigations. The students record their observations in a table. Investigation
Observations
1
A beaker of water is
heated on a hot plate. Bubbles form in
the water, and steam is given off.
2
Oil is added to a beaker of water. Oil forms a layer on top
of the water
3
Sand and iron filings are mixed in a beaker. A magnet is
then used to separate the iron filings from the sand.
4
A piece of chalk is placed in a beaker of vinegar Bubbles
form as a gas is given off.
Which investigation most likely involved a chemical reaction?