Intro to Chemical Equations

The Law of Conservation of Matter states that

• matter is neither created or destroyed during a chemical reaction; only transformed.

• for every action, there is an equal and opposite reaction.

• matter can be created or destroyed during a chemical reaction.

• matter and energy are the same thing.

Tags

NGSS.MS-PS1-5

Which of the following best describes the purpose of a chemical equation?

• To represent the physical properties of a substance or substances.

• To describe a chemical reaction in terms of symbols and formulas.

• To illustrate the melting points of different compounds.

• To show the boiling points of various elements.

Tags

NGSS.MS-PS1-5

What does the arrow in a chemical equation represent?

• the direction of the chemical reaction

• the separation of substances that react with one another from the substances formed after a reaction

• the point that separates the reactants from the products

• All of these answers are correct.

The substances that go into a chemical reaction are found on the ___ side of the arrow in a chemical equation. They are called the ___.

• left, reactants

• left, products

• right, reactants

• right, products

Tags

NGSS.MS-PS1-5

The substances that come out of a chemical reaction are found on the ___ side of the arrow in a chemical equation. They are called the ___.

• left, reactants

• left, products

• right, reactants

• right, products

Tags

NGSS.MS-PS1-5

The number in front of a chemical formula is called the ___, which represents the number of molecules or moles of that substance.

• coefficient

• subscript

• superscript

• product

The small number after a chemical symbol is called the ___, which represents the number of atoms of that element.

• coefficient

• subscript

• superscript

• product

What type of reaction is this? 2H₂ + O₂ → 2H₂O

• synthesis

• decomposition

• combustion

• double replacement

• single replacement

What type of reaction is this? Zn + CuCl₂ → Cu + ZnCl₂

• synthesis

• decomposition

• combustion

• double replacement

• single replacement

What type of reaction is this? CH₄ + 2O₂ → CO₂ + 2H₂O

• synthesis

• decomposition

• combustion

• double replacement

• single replacement