Classifying and Balancing Equations

Front

What is a balanced chemical equation?

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 during the reaction.

Front

How do you determine the number of oxygen atoms in a compound like Al₂(SO₄)₃?

Back

Count the oxygen atoms in the sulfate ion (SO₄) which has 4 oxygen atoms, and since there are 3 sulfate ions in Al₂(SO₄)₃, multiply 4 by 3 to get 12 oxygen atoms.

Front

What does it mean if an equation is not balanced?

Back

It means that the number of atoms of at least one element is different on the reactant side compared to the product side, violating the law of conservation of mass.

Front

How do you balance the equation HgO → 2Hg + O₂?

Back

You need to add a coefficient of 2 in front of HgO to balance the equation: 2HgO → 2Hg + O₂.

Front

What is the coefficient needed to balance the equation Mg + __HCl → MgCl₂ + H₂?

Back

You need a coefficient of 2 in front of HCl to balance the equation: Mg + 2HCl → MgCl₂ + H₂.

Front

What is the purpose 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

How do you identify the reactants and products in a chemical equation?

Back

Reactants are the substances that undergo a chemical change, found on the left side of the equation, while products are the substances formed, found on the right side.

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 balance the equation PCl₅ + __H₂O → __HCl + H₃PO₄?

Back

You need coefficients of 4 for H₂O and 5 for HCl to balance the equation: PCl₅ + 4H₂O → 5HCl + H₃PO₄.

Front

What is a skeleton equation?

Back

A skeleton equation is a chemical equation that shows the reactants and products but not the coefficients needed to balance it.