Chemical Changes

Four substances were mixed with a clear liquid. The observations are recorded in the table shown below. Based on the observations, which mixture produced the best evidence that a new substance was formed?

• Substance 1

• Substance 2

• Substance 3

• Substance 4

Two items are combined inside a balloon. The balloon is tied shut. What observation would indicate that mixing the chemical produced a gas?

• The balloon can hold a liquid.

• The balloon increases in volume.

• The balloon becomes cold.

• The balloon was tied shut.

Students heat a white solid in a test tube over a flame. What observation would tell the students that the solid has become a new substance?

• The temperature of the solid increases.

• The color of the solid changes to amber.

• The solid begins to melt within the test tube.

• The solid is in the form of crystals.

A liquid and a solid are combined to form a mixture. Which procedure would most likely produce evidence that a chemical change occurs?

• Observe the color both of the liquid and the solid before mixing.

• Measure the volume of the mixture after the components were combined.

• Determine the time it took for the liquids to combine completely.

• Record the temperature of the substances before and after mixing.

Two clear substances are combined inside a plastic bag. The plastic bag is tightly sealed. What observation would indicate that mixing the chemical produced a new substance?

• The substance in the bag becomes warm.

• The bag is transparent.

• The substances are clear.

• The bag can hold a liquid.

Which four signs indicate a chemical change has taken place.

• Production fo gas

• Precipitate

• Color Chance

• Temperature Change

• Change in shape