7th - Counting Atoms, Classifying and Balancing Equations

Front

What is the formula to calculate the number of oxygen atoms in a compound like Al₂(SO₄)₃?

Back

Multiply the number of sulfate groups (SO₄) by the number of oxygen atoms in each sulfate (4). In Al₂(SO₄)₃, there are 3 sulfate groups, so 3 x 4 = 12 oxygen atoms.

Front

How many hydrogen atoms are present in 4H₂O?

Back

There are 4 water molecules (H₂O), and each has 2 hydrogen atoms. Therefore, 4 x 2 = 8 hydrogen atoms.

Front

What does it mean for a chemical equation to be balanced?

Back

A balanced chemical equation has the same number of each type of atom on both sides of the equation, indicating that mass is conserved.

Front

Identify the reactants in the equation: 2H₂ + O₂ → 2H₂O.

Back

The reactants are the substances that undergo a chemical change, which are 2H₂ (hydrogen gas) and O₂ (oxygen gas).

Front

What are products in a chemical reaction?

Back

Products are the substances formed as a result of a chemical reaction, found on the right side of the equation.

Front

How do you balance the equation: Mg + HCl → MgCl₂ + H₂?

Back

You need 2 HCl to balance the equation: Mg + 2HCl → MgCl₂ + H₂.

Front

What is the significance of coefficients in a chemical equation?

Back

Coefficients indicate the number of molecules or moles of a substance involved in the reaction, helping to balance the equation.

Front

What is the law of conservation of mass?

Back

The law 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 number of atoms in a compound like C₆H₁₂O₆?

Back

Count the subscripts: 6 carbon (C), 12 hydrogen (H), and 6 oxygen (O) atoms, totaling 24 atoms.

Front

What is a chemical equation?

Back

A chemical equation is a symbolic representation of a chemical reaction, showing the reactants and products along with their quantities.