Chemical Changes and Balanced or Unbalanced Chemical Equations

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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 breaking glass.

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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. Examples include rusting, burning, and digestion.

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What are reactants in a chemical equation?

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Reactants are the starting substances in a chemical reaction, found on the left side of a chemical equation.

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What are products in a chemical equation?

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Products are the substances formed as a result of a chemical reaction, found on the right side of a chemical equation.

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What is an exothermic reaction?

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An exothermic reaction is a chemical reaction that releases energy in the form of heat, causing the surroundings to feel warm.

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What is an endothermic reaction?

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An endothermic reaction is a chemical reaction that absorbs energy from its surroundings, causing the surroundings to feel cold.

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What is a balanced chemical equation?

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A balanced chemical equation has the same number of each type of atom on both sides of the equation, indicating that mass is conserved.

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What is an unbalanced chemical equation?

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An unbalanced chemical equation does not have the same number of each type of atom on both sides, meaning mass is not conserved.

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What is the law of conservation of mass?

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The law of conservation of mass states that mass cannot be created or destroyed in a chemical reaction; it can only change forms.

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What is a catalyst?

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A catalyst is a substance that speeds up a chemical reaction without being consumed in the process.