Question

physical and chemical changes
instructions: a physical change can be described as a change that doesnt affect the chemical composition of the substance; while a chemical change does alter the chemical composition of the substance. place the following examples under the correct heading that describes the change that occurs.
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a gas explodes in the air, a raw egg is fried, a salt dissolves in water, copper metal conducts an electrical current, nitrogen gas and hydrogen gas combine and form ammonia, water is separated into hydrogen and oxygen gas by electrolysis, ice melting, milk sours, rusting of a nail, sublimation of dry ice
physical change
chemical change
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Explanation:

A physical change only affects physical properties like state, without altering chemical composition. A chemical change results in new substances with different chemical properties. For a gas exploding in air, a chemical reaction occurs, so it's a chemical change. Frying a raw - egg changes its chemical structure, so it's chemical. Salt dissolving in water is a physical change as salt can be recovered by evaporation. Copper conducting electricity is a physical property, so it's a physical change. Nitrogen and hydrogen combining to form ammonia is a chemical reaction. Water electrolysis to form hydrogen and oxygen is a chemical change. Ice melting is a physical change of state. Milk souring is a chemical change due to bacterial action. Rusting of a nail is a chemical change as iron forms iron oxide. Sublimation of dry - ice is a physical change of state.

Answer:

Physical Change: a salt dissolves in water, copper metal conducts an electrical current, ice melting, sublimation of dry ice
Chemical Change: a gas explodes in the air, a raw egg is fried, nitrogen gas and hydrogen gas combine and form ammonia, water is separated into hydrogen and oxygen gas by electrolysis, milk sours, rusting of a nail