physical or chemical change

1. a water molecule gains enough energy to enter the vapor phase?

2. anti freeze is added to a car radiator to lower the freezing point.

3. a glowing splint placed in a test tube causes it to make a loud "pop"

1)physical

2)not sure but would say chemical
3)most likely a physical

1. This is a physical change. When a water molecule gains enough energy to enter the vapor phase (evaporate), it undergoes a physical change. Physical changes are reversible and do not involve a change in the chemical composition of the substance.

2. This is a physical change. When antifreeze is added to a car radiator to lower the freezing point, it changes the physical properties of the mixture. Antifreeze typically contains chemicals that prevent the water in the radiator from freezing at lower temperatures. This is a physical change because it alters the freezing point without changing the chemical composition of the antifreeze or the water.

3. This is a chemical change. When a glowing splint is placed in a test tube and it causes a loud "pop," it indicates a chemical reaction has taken place. The "pop" sound is often associated with the combustion of hydrogen gas produced from the reaction. The chemical composition of the substances involved in the reaction has changed, leading to the production of a new substance(s). In this case, hydrogen gas is being produced by the reaction.