Physical Science Chemical/Physical Changes

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What is a chemical change?

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A chemical change is a process where substances combine or break apart to form new substances with different properties. Examples include rusting, burning, and tarnishing.

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What is a physical change?

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A physical change is a change that affects one or more physical properties of a substance without altering its chemical composition. Examples include melting, freezing, and dissolving.

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What are the signs of a chemical change?

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Signs of a chemical change include color change, temperature change, gas production, and the formation of a precipitate.

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What is reactivity in chemistry?

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Reactivity refers to how readily a substance undergoes a chemical reaction with other substances. Highly reactive substances can easily form new compounds.

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What is pH?

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pH is a scale used to measure the acidity or basicity of a solution, ranging from 0 (very acidic) to 14 (very basic), with 7 being neutral.

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What are acids?

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Acids are substances that donate protons (H+) in a solution and have a pH less than 7. Examples include hydrochloric acid and citric acid.

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What are bases?

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Bases are substances that accept protons (H+) or donate hydroxide ions (OH-) in a solution and have a pH greater than 7. Examples include sodium hydroxide and ammonia.

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What is a salt in chemistry?

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A salt is a compound formed from the reaction of an acid and a base, consisting of metal and non-metal ions.

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What is tarnishing?

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Tarnishing is a chemical change that occurs when metals react with sulfur compounds in the air, forming a dull coating.

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What is rusting?

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Rusting is a specific type of corrosion that occurs when iron reacts with oxygen and moisture, forming iron oxide (rust).