Chemical Formulas, Equations & Reactions

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What is a chemical formula?

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A chemical formula is a way of expressing the composition of a substance using symbols for its constituent elements and numbers to indicate the ratio of atoms.

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What does the subscript in a chemical formula indicate?

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The subscript indicates the number of atoms of the element in the molecule. For example, in H₂O, the '2' indicates there are 2 hydrogen atoms.

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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, following the law of conservation of mass.

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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 is neither created nor destroyed in a chemical reaction; the total mass of reactants equals the total mass of products.

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What is a reactant in a chemical reaction?

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A reactant is a substance that undergoes change during a chemical reaction, found on the left side of the equation.

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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, found on the right side of the equation.

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What is a decomposition reaction?

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A decomposition reaction is a type of chemical reaction where one compound breaks down into two or more simpler substances.

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What is a synthesis reaction?

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A synthesis reaction is a type of chemical reaction where two or more simple substances combine to form a more complex substance.

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What is the difference between an endothermic and exothermic reaction?

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An endothermic reaction absorbs energy (heat) from its surroundings, while an exothermic reaction releases energy (heat) to its surroundings.

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How do you determine if a chemical equation is balanced?

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To determine if a chemical equation is balanced, count the number of atoms of each element on both sides of the equation and ensure they are equal.