S1 Final Review Flashcard

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What is an element?

Back

An element is a pure substance that cannot be broken down into simpler substances by chemical means. Examples include hydrogen (H), oxygen (O), and gold (Au).

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What is a compound?

Back

A compound is a substance formed when two or more elements are chemically bonded together. Examples include water (H2O) and carbon dioxide (CO2).

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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. Examples include air and salad.

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How do you convert scientific notation to standard notation?

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To convert from scientific notation to standard notation, multiply the number by 10 raised to the power indicated. For example, 4.53 x 10^10 = 45300000000.

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What is a chemical change?

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A chemical change occurs when substances combine or break apart to form new substances, often accompanied by energy changes. An example is the formation of bubbles when vinegar and baking soda react.

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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 ice or dissolving sugar in water.

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How do you convert grams to moles?

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To convert grams to moles, divide the mass of the substance by its molar mass. For example, for CH4, the molar mass is 16 g/mol, so 50 g of CH4 = 50 g / 16 g/mol = 3.13 moles.

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What is the molar mass of CH4?

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The molar mass of CH4 (methane) is 16 g/mol, calculated as follows: C (12 g/mol) + 4H (4 g/mol) = 16 g/mol.

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What is an ionic compound?

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An ionic compound is formed when electrons are transferred from one atom to another, resulting in the formation of charged ions. Example: sodium chloride (NaCl).

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What is a covalent compound?

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A covalent compound is formed when two or more atoms share electrons. Example: carbon dioxide (CO2).