Unit 7 Review - Chemical Equations

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What is a physical change?

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A physical change involves a change in state, such as melting, freezing, or boiling, without altering the chemical composition of the substance.

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What is a chemical change?

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A chemical change involves a transformation that alters the chemical composition of a substance, resulting in the formation of new substances.

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How can you identify a physical change versus a chemical change?

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A physical change can often be reversed and does not produce new substances, while a chemical change results in new substances and is usually irreversible.

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What does it mean to balance a chemical equation?

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Balancing a chemical equation means ensuring that the number of atoms for each element is the same on both sides of the equation, adhering to the law of conservation of mass.

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What is the significance of ΔH in a chemical reaction?

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ΔH represents the change in enthalpy (heat content) during a reaction; a negative ΔH indicates an exothermic reaction, while a positive ΔH indicates an endothermic reaction.

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What is an exothermic reaction?

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An exothermic reaction is a chemical reaction that releases energy, usually in the form of heat, to its surroundings.

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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, resulting in a decrease in temperature.

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What is the general form of a chemical equation?

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A chemical equation typically has reactants on the left side, products on the right side, and an arrow indicating the direction of the reaction.

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What does it mean if energy is a product in a chemical equation?

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If energy is a product in a chemical equation, it indicates that energy is released during the reaction, characterizing it as exothermic.

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What does it mean if energy is a reactant in a chemical equation?

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If energy is a reactant in a chemical equation, it indicates that energy is absorbed during the reaction, characterizing it as endothermic.