Identify each of the following as a physical change or a chemical change, and give reasons for your answer. (a) water droplets forming on the bathroom mirror (b) grinding wheat into flour (c) toasting marshmallows (d) making a peanut butter and jelly sandwich (e) lighting a Bunsen burner (f) dissolving sugar in tea (g) beating a raw egg until it is creamy

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a. Physical change: The water vapor that comes in contact with the cool mirror condenses, they undergo a physical change when they turn into the liquid form.

b. Physical change: Grinding is a physical change. The process may change the size and texture of the substance but it does not change its chemical properties.

c. Chemical change: When heat is applied in the marshmallow, the sugar molecules are turned into a new substance; hence, its chemical properties changed. This process is impossible to undo. The marshmallow cannot change back in its original form.

d. Physical change: Making a peanut butter jelly sandwich does not involve cooking. The chemical identities of the bread, peanut butter, and jelly are still the same.

e. Chemical change: Lighting a Bunsen burner involves burning a gas. This results in the formation of new substances such as water vapor and carbon dioxide.

f. Physical change: Dissolving is a physical change because the sugar did not undergo changes in its chemical composition; hence, it is still sugar and it can be returned into its original state by evaporating the liquid.

g. Physical change: Beating the egg would change its physical properties and force air into the liquid, but it does not produce a new substance.

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