MCQs on Compounds and Formulae

What is a compound?

• A mixture of substances

• A pure substance made of only one kind of atom

• A substance made of different atoms chemically bonded

• A substance that can be separated physically

Which of the following is a compound?

• Oxygen

• Iron

• Water

• Hydrogen

What is the correct name for the compound NaCl?

• Sodium chlorine

• Chloride sodium

• Sodium chloride

• Sodium chlorate

Which suffix is commonly used for compounds with two elements?

• -ide

• -ate

• -ium

• -ene

Which of the following is an element?

• H₂O

• CO₂

• O₂

• NaCl

What does the small number in a chemical formula tell us?

• Number of molecules

• Number of atoms of that element

• Number of bonds

• Mass

Which compound contains three elements?

• H₂

• NaCl

• CaCO₃

• O₂

What is the correct formula for carbon dioxide?

• CO

• CO₂

• C₂O

• O₂C

What is wrong with the name "sulfur calcium" for a compound?

• Metals should come second

• Non-metals are written first

• The order of elements is incorrect

• There’s no such compound

Which element is common in all hydroxides?

• Hydrogen

• Sodium

• Oxygen

• Both A and C