How many of the following are true concerning balanced chemical equations?
I. The number of molecules is conserved.
II. The coefficients for the reactants tell you how much of each reactant you are given.
III. Atoms are neither created nor destroyed.
IV. The coefficients indicate the mass ratios of the substances used.
V. The sum of the coefficients on the reactant side equals the sum of the coefficients on
the product side.
a) 1
b) 2
c) 3
d) 4
e) 5
Look at III and IV as true. What do you think?
Three of the statements are true concerning balanced chemical equations:
III. Atoms are neither created nor destroyed. This principle is known as the law of conservation of mass.
IV. The coefficients indicate the mass ratios of the substances used. The coefficients in a balanced chemical equation represent the relative amounts of substances involved in the reaction, and they can be used to determine the mass ratios.
V. The sum of the coefficients on the reactant side equals the sum of the coefficients on the product side. This principle is known as the law of conservation of atoms.
Therefore, the correct answer is c) 3.
To determine how many of the statements are true concerning balanced chemical equations, let's analyze each statement one by one:
I. The number of molecules is conserved.
This statement is true. In a balanced chemical equation, the number of atoms on the reactant side is equal to the number of atoms on the product side. This means that the number of molecules is conserved during a chemical reaction.
II. The coefficients for the reactants tell you how much of each reactant you are given.
This statement is false. The coefficients in a balanced chemical equation do not indicate the quantities of reactants given. Instead, they represent the relative ratios of the reactants and products involved in the reaction.
III. Atoms are neither created nor destroyed.
This statement is true. According to the Law of Conservation of Mass, the total number of atoms before a chemical reaction must be the same as the total number of atoms after the reaction. Atoms cannot be created or destroyed during the reaction; they only rearrange to form different molecules.
IV. The coefficients indicate the mass ratios of the substances used.
This statement is true. The coefficients in a balanced chemical equation represent the relative amounts of substances used in the reaction. These coefficients can be used to calculate the mass ratios of the reactants and products involved.
V. The sum of the coefficients on the reactant side equals the sum of the coefficients on the product side.
This statement is true. In a balanced chemical equation, the total number of atoms on the reactant side must equal the total number of atoms on the product side. This conservation of atoms is achieved by adjusting the coefficients of the reactants and products.
Based on our analysis:
Statement I is true.
Statement II is false.
Statement III is true.
Statement IV is true.
Statement V is true.
Therefore, there are 4 statements that are true concerning balanced chemical equations. Hence, the correct answer is option d) 4.