Chemistry Quiz
Questions: 16 · 10 minutes
1. In the change Fe²⁺ → Fe³⁺ + e⁻, what happens to the iron ion?
It is oxidized because it loses an electron
It is reduced because it gains an electron
It is reduced because it gains a proton
It is oxidized because it gains an electron
2. Why do elements in the same vertical group of the periodic table often have similar chemical behavior?
They have identical atomic masses
They have similar valence-electron arrangements
They contain the same number of occupied electron shells
They have equal numbers of protons and neutrons
3. How does a catalyst usually increase the rate of a chemical reaction?
It permanently shifts the equilibrium toward the products
It provides an alternative pathway with lower activation energy
It is consumed to provide energy to the reactants
It raises the temperature of the reacting mixture
4. Which coefficient should be placed before O₂ to balance CH₄ + O₂ → CO₂ + 2H₂O?
2
1
3
One-half
5. Which substance is composed primarily of ions in its solid state?
Carbon dioxide, CO₂
Methane, CH₄
Magnesium oxide, MgO
Hydrogen chloride, HCl
6. Two atoms are isotopes of the same element. How do they differ?
They have the same number of protons but different numbers of neutrons
They have different numbers of protons but the same number of neutrons
They have different numbers of electrons but identical nuclei
They have the same mass number but different atomic numbers
7. A solution contains 5.0 g of solute in a total volume of 100 mL. What is its concentration in grams per liter?
500 g/L
5 g/L
0.50 g/L
50 g/L
8. A student adds zinc metal to hydrochloric acid and observes bubbles. Which gas is produced?
Oxygen
Carbon dioxide
Chlorine
Hydrogen
9. Water has a much higher boiling point than methane, even though both are small molecules. What best explains this difference?
Water is ionic, while methane is covalent
Methane atoms are held together by metallic bonds
Water molecules form strong hydrogen bonds with one another
Water molecules contain more electrons than methane molecules
10. A reusable hand warmer releases heat as a dissolved substance crystallizes. Which description best fits the energy transfer?
The process is exothermic because the system releases heat to the surroundings
The process is endothermic because the system becomes warmer
The process is endothermic because the surroundings release heat
The process is exothermic because heat flows from the surroundings into the system
11. When preparing a dilute aqueous acid solution from a concentrated acid, which procedure is appropriate?
Add water quickly to the concentrated acid
Add the acid slowly to the water while stirring and using suitable protective equipment
Use either order because stirring prevents hazardous heating
Pour the acid and water together simultaneously
12. The molar mass of water is approximately 18.0 g/mol. How many moles are in 18.0 g of water?
18.0 mol
0.50 mol
1.00 mol
324 mol
13. A strong acid solution has a pH of 2. It is diluted tenfold with water under ideal conditions. What is its approximate new pH?
12
1
2
3
14. For the reaction 2H₂ + O₂ → 2H₂O, a container starts with 3 mol of H₂ and 2 mol of O₂. Which reactant is limiting?
O₂
H₂
Both reactants are present in exact stoichiometric amounts
The limiting reactant cannot be found from the amounts given
15. What does the atomic number of an element represent?
The average mass of the element's naturally occurring atoms
The total number of protons and neutrons in each atom
The number of electron shells in a neutral atom
The number of protons in each atom of the element
16. For the equilibrium N₂(g) + 3H₂(g) ⇌ 2NH₃(g), how does increasing pressure by decreasing the container volume affect the equilibrium at constant temperature?
It shifts left, toward N₂ and H₂
It causes no shift because all substances are gases
It shifts right, toward NH₃
It stops both the forward and reverse reactions