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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 changes in state (like melting or freezing) and changes in appearance (like dissolving).

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What is a chemical change?

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A chemical change is a change that results in the formation of new chemical substances. It involves the breaking and forming of bonds between atoms. Examples include rusting, burning, and digestion.

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What happens to the particles in a solid?

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In a solid, particles are closely packed together and vibrate in place, but they do not move freely.

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What is an exothermic reaction?

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An exothermic reaction is a chemical reaction that releases heat to its surroundings, resulting in an increase in temperature. Examples include combustion and respiration.

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What is an endothermic reaction?

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An endothermic reaction is a chemical reaction that absorbs heat from its surroundings, resulting in a decrease in temperature. Examples include photosynthesis and melting ice.

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What is the difference between a physical change and a chemical change?

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A physical change alters the form or appearance of a substance without changing its chemical composition, while a chemical change results in the formation of new substances with different properties.

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What is a phase change?

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A phase change is a transition of matter from one state (solid, liquid, gas) to another, such as melting, freezing, condensation, and evaporation.

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What is melting?

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Melting is the process of a solid turning into a liquid when heat is applied.

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What is freezing?

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Freezing is the process of a liquid turning into a solid when heat is removed.

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What is evaporation?

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Evaporation is the process by which molecules in a liquid gain enough energy to enter the gaseous state.