Final Review 2nd Semester - Physical Science

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What is Decomposition in chemistry?

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Decomposition is a type of chemical reaction where one compound breaks down into two or more simpler substances. Example: NO2 → N2 + O2.

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What is a Chemical Change?

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A chemical change is a process that results in the formation of one or more new substances with different chemical properties. Example: Rusting of iron.

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What is the Atomic Number?

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The atomic number is the number of protons in the nucleus of an atom, which determines the element's identity. Example: The atomic number of Lithium (Li) is 3.

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What is a Mixture?

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A mixture is a combination of two or more substances that are not chemically bonded. Example: Salt water is a mixture of salt (NaCl) and water.

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What is a Compound?

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A compound is a substance formed when two or more elements are chemically bonded together. Example: Sodium chloride (NaCl) is a compound.

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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. Example: Melting ice.

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What is the difference between an Element and a Compound?

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An element is a pure substance that cannot be broken down into simpler substances, while a compound is made up of two or more elements chemically combined.

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What is the Law of Conservation of Mass?

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The law states that mass is neither created nor destroyed in a chemical reaction; it is conserved.

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What is a Reactant?

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A reactant is a substance that undergoes a chemical change in a reaction. Example: In the reaction 2H2 + O2 → 2H2O, H2 and O2 are reactants.

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What is a Product in a chemical reaction?

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A product is a substance that is formed as a result of a chemical reaction. Example: In the reaction 2H2 + O2 → 2H2O, H2O is the product.