8 Holt Chemical Reactions Overview

A change that results in the formation of new substances with different properties.

A change that doesn't lead to the formation of new substances. The original substances remain, but their physical state or appearance might change.

Evidence that suggests a chemical change might have occurred. Examples include heat, light, sound, and changes in color, odor, or temperature.

A substance that is formed during a chemical reaction.

A substance that is used up in a chemical reaction.

A chemical change that includes the release of energy.

A chemical change that requires energy to occur.

A chemical analysis that confirms the formation of a new substance.

A symbol indicating the physical state of a substance in a chemical reaction, such as solid (s), liquid (l), gas (g), or aqueous solution (aq).

A symbol that indicates a chemical reaction can occur in both the forward and reverse directions, leading to a mixture of reactants and products.

The temperature at which a chemical reaction takes place.

The pressure at which a chemical reaction takes place.

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

A substance that is dissolved in a liquid, forming a homogeneous mixture.

The process of adjusting coefficients in a chemical equation to ensure the same number of atoms of each element appears on both the reactant and product sides.

A whole number placed in front of a chemical formula in a balanced chemical equation, indicating the number of molecules or formula units involved in the reaction.

A chemical representation of a reaction, showing the formulas of reactants, products, and their stoichiometric coefficients.

The process of combining chemical elements or compounds to form new substances with different properties.

When a chemical equation has the same number of atoms of each element on both sides, ensuring that the law of conservation of mass is upheld.

The ratio of reactants and products in a balanced chemical equation; it reflects the proportions in which substances react and are formed.

A chemical reaction where two or more reactants combine to form a single product.

A chemical reaction where a single reactant breaks down into two or more products.

A chemical reaction where a substance reacts with oxygen, releasing energy in the form of heat and light.

The process of determining the products of a chemical reaction based on the reactants and the types of reactions involved.

Molecules and atoms of reactants must come into contact with each other for a chemical reaction to occur. This is like bumping into someone for them to notice you.

An example of a chemical reaction where energy is absorbed from the surroundings, represented by dinitrogen tetroxide decomposing into nitrogen dioxide.

It indicates how many atoms of a certain element are present in a molecule or compound. It is a small number written as a subscript next to an element's symbol in a chemical formula.

A chemical equation is balanced when the number of atoms of each element on the reactants' side (left side) equals the number of atoms of that element on the products' side (right side).

Coefficients are numbers placed in front of chemical formulas in a balanced chemical equation. They indicate the relative number of molecules or formula units involved in the reaction. Subscripts are numbers written below and to the right of an element's symbol in a chemical formula. They indicate the number of atoms of that element in a molecule or formula unit.

A word equation describes a chemical reaction using the names of the reactants and products. For example, the reaction of hydrogen and oxygen to form water can be written as 'hydrogen + oxygen → water'.

An unbalanced formula equation represents a chemical reaction using chemical formulas but without balancing the number of atoms on both sides. For example, the reaction of hydrogen and oxygen to form water can be written as 'H2 + O2 → H2O'.

A balanced formula equation is a chemical equation where the number of each type of atom is the same on both the reactant and product sides. This ensures that the law of conservation of mass is obeyed.

The law of conservation of mass states that in a closed system, the total mass of the reactants before a chemical reaction must equal the total mass of the products after the reaction. In other words, matter cannot be created or destroyed in chemical reactions.

In a chemical equation, the reactants are the substances that are consumed in a chemical reaction. They are typically written on the left side of the equation.

In a chemical equation, the products are the substances that are formed as a result of a chemical reaction. They are typically written on the right side of the equation.