Chemists use symbols and formulae to represent elements and compounds. Word equations and balanced chemical equations represent the changes that happen in chemical reactions.
What is the chemical symbol for the element mercury?
What is the chemical formula for chlorine?
What is the name of the compound with the formula MgBr2?
How many different types of atom are in one molecule of a substance that has the formula N2O4?
What is the formula of water?
What is the best definition of a compound?
A substance made up of two or more elements that are chemically combined
A substance made up of two or more elements that are chemically combined in fixed proportions
A substance made up of two elements that are chemically combined in fixed proportions
What is the formula of a substance made up of Al3+ ions and O2- ions?
What are the reactants in this word equation?
sodium hydroxide + hydrochloric acid → sodium chloride + water
Sodium hydroxide and sodium chloride
Sodium hydroxide and hydrochloric acid
Sodium chloride and water
Which numbers correctly fill the gaps to balance this equation?
__Na + Cl2 → __NaCl
C3H8 + __O2 → __CO2 + __H2O
3, 3, 2
10, 3, 8
5, 3, 4