Balancing Chemical Equations Flashcard

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 balance the equation H2 + Cl2 -> HCl?

Back

The balanced equation is H2 + Cl2 -> 2HCl, meaning one molecule of hydrogen reacts with one molecule of chlorine to produce two molecules of hydrochloric acid.

Front

What is the Law of Conservation of Matter/Mass?

Back

The Law of Conservation of Matter/Mass states that matter cannot be created or destroyed in a chemical reaction; the total mass of reactants equals the total mass of products.

Front

What are coefficients in a chemical equation?

Back

Coefficients are the numbers placed before compounds in a chemical equation to indicate how many molecules or moles of each reactant and product are involved.

Front

What are subscripts in a chemical formula?

Back

Subscripts are the small numbers written after an element symbol in a chemical formula that indicate the number of atoms of that element in a molecule.

Front

Why can't subscripts be changed when balancing equations?

Back

Changing subscripts alters the identity of the substance, which is not allowed when balancing equations; only coefficients can be adjusted.

Front

What is an unbalanced chemical equation?

Back

An unbalanced chemical equation does not have the same number of each type of atom on both sides, meaning it does not obey the Law of Conservation of Matter.

Front

What is the mass of products if 8 grams of iron and 5 grams of sulfur react?

Back

The mass of products is equal to 13 grams, as mass is conserved in a chemical reaction.

Front

Identify an unbalanced equation: CaCO3 -> CaO + CO2, PbO2 + 2H2 -> 2Pb + H2O, 2Na + 2H2O -> 2NaOH + H2, CS2 + 2O2 -> CO2 + 2SO2.

Back

PbO2 + 2H2 -> 2Pb + H2O is unbalanced because the number of hydrogen and oxygen atoms is not the same on both sides.

Front

What is the role of reactants in a chemical reaction?

Back

Reactants are the starting substances that undergo a chemical change to form products.