Atoms, Molecules, and Chemical Reactions

Front

What is an atom?

Back

An atom is the smallest unit of matter that retains the properties of an element. It consists of a nucleus made of protons and neutrons, surrounded by electrons.

Front

What is a molecule?

Back

A molecule is a group of two or more atoms bonded together. Molecules can consist of the same or different types of atoms.

Front

What is a chemical reaction?

Back

A chemical reaction is a process that involves the rearrangement of the molecular or ionic structure of a substance, resulting in the formation of new substances.

Front

What does it mean to balance a chemical equation?

Back

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

Front

What is the law of conservation of mass?

Back

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.

Front

How do you determine the mass of products in a chemical reaction?

Back

To determine the mass of products, add the masses of all reactants. The total mass before the reaction equals the total mass after the reaction.

Front

What is a reactant?

Back

A reactant is a substance that undergoes a chemical change in a reaction. Reactants are found on the left side of a chemical equation.

Front

What is a product?

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A product is a substance that is formed as a result of a chemical reaction. Products are found on the right side of a chemical equation.

Front

How many atoms are in the molecule HCl?

Back

HCl contains 2 atoms: 1 hydrogen atom and 1 chlorine atom.

Front

What is the difference between an element and a compound?

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An element is a pure substance made of only one type of atom, while a compound is a substance formed when two or more different types of atoms bond together.