To be useful, a chemical equation must be balanced. What does this mean? The volume of the reactants and products must be equal.

The number of each type of atom on both sides of the arrow must be equal.

The masses of the products and reactants must be equal.

The amount of gas/solid/liquid on both sides of the arrow must be equal.

The diagram shows the structures of horse and cat forelimbs. what does the diagram suggest about the evolutionary relationship between these two mammals? a. they have homologous structures, indicating a common ancestor. b. they have analogous structures, indicating a common ancestor. c. they have homologous structures, indicating that they do not have a common ancestor. d. they have analogous structures, indicating that they do not have a common ancestor.

Which statement describes covalent bases? they have hydroxide ions. they produce hydrogen ions. they are often amines. they are named the same as ionic compounds.

What is avogadro’s number, and why is it useful