Science: Middle School: Grades 6, 7 and 8 Quiz - Compounds (Questions)

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In Science terms, a chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions. There are literally billions of compounds!

1. A compound is a substance which contains .......
[ ] only one type of atom
[ ] only two types of atom
[ ] two or more chemicals which can be easily separated
[ ] two or more elements chemically joined together
2. The number of different elements in calcium carbonate (CaCO3) is .......
[ ] 2
[ ] 3
[ ] 4
[ ] 5
3. Which of the following could have been formed by reacting iron with sulfur?
[ ] Iron oxide
[ ] Sulfuric iron
[ ] Iron sulfide
[ ] Sulphuric acid
4. The formula of methane is CH4. Which of these is true?
[ ] A molecule of methane contains five atoms
[ ] A molecule of methane contains five different elements
[ ] An atom of methane contains two different elements
[ ] Methane contains five molecules
5. Which of these is NOT a compound?
[ ] Carbon monoxide
[ ] Chlorine
[ ] Hydrochloric acid
[ ] Propane
6. How many atoms in the formula CuSO4?
[ ] 3
[ ] 4
[ ] 6
[ ] 7
7. The correct formula for carbon tetrachloride is .......
[ ] C3Cl
[ ] C4Cl
[ ] CCl3
[ ] CCl4
8. The smallest particle of carbon dioxide (CO2) that still has the properties of carbon dioxide is called .......
[ ] a molecule
[ ] a proton
[ ] an atom
[ ] an ion
9. Which of these word equations is INCORRECT?
[ ] Copper + oxygen → copper oxide
[ ] Hydrogen + chlorine → hydrogen chlorine
[ ] Iron + chlorine → iron chloride
[ ] Magnesium + oxygen → magnesium oxide
10. Which is the correct formula equation?
[ ] Mg + O → MgO
[ ] Mg + O2 → MgO2
[ ] 2 Mg + O2 → Mg2O2
[ ] 2 Mg + O2 → 2 MgO
Science: Middle School: Grades 6, 7 and 8 Quiz - Compounds (Answers)
1. A compound is a substance which contains .......
[ ] only one type of atom
[ ] only two types of atom
[ ] two or more chemicals which can be easily separated
[x] two or more elements chemically joined together
2. The number of different elements in calcium carbonate (CaCO3) is .......
[ ] 2
[x] 3
[ ] 4
[ ] 5
Ca, C and O
3. Which of the following could have been formed by reacting iron with sulfur?
[ ] Iron oxide
[ ] Sulfuric iron
[x] Iron sulfide
[ ] Sulphuric acid
There are two elements joining together so the name ends in -ide
4. The formula of methane is CH4. Which of these is true?
[x] A molecule of methane contains five atoms
[ ] A molecule of methane contains five different elements
[ ] An atom of methane contains two different elements
[ ] Methane contains five molecules
Methane exists as molecules and has two different elements
5. Which of these is NOT a compound?
[ ] Carbon monoxide
[x] Chlorine
[ ] Hydrochloric acid
[ ] Propane
Chlorine is an element
6. How many atoms in the formula CuSO4?
[ ] 3
[ ] 4
[x] 6
[ ] 7
One Cu, one S, four O
7. The correct formula for carbon tetrachloride is .......
[ ] C3Cl
[ ] C4Cl
[ ] CCl3
[x] CCl4
8. The smallest particle of carbon dioxide (CO2) that still has the properties of carbon dioxide is called .......
[x] a molecule
[ ] a proton
[ ] an atom
[ ] an ion
9. Which of these word equations is INCORRECT?
[ ] Copper + oxygen → copper oxide
[x] Hydrogen + chlorine → hydrogen chlorine
[ ] Iron + chlorine → iron chloride
[ ] Magnesium + oxygen → magnesium oxide
10. Which is the correct formula equation?
[ ] Mg + O → MgO
[ ] Mg + O2 → MgO2
[ ] 2 Mg + O2 → Mg2O2
[x] 2 Mg + O2 → 2 MgO