Chemistry CIA #3 Review

Which of the following equations represents a synthesis reaction?

• CaCO3 (s) → CaO (s) + CO2 (g)

• H2 (g) + Cl2 (g) → 2HCl (g)

• CaI2 (s) + Cl2 (g)→ CaCl2 (s) + I2 (g)

• AgNO3 (aq) + NaOH (aq) → AgOH (s) + NaNO3 (aq)

All of the following factors contribute to increasing the rate of chemical reactions except for:

• Increasing the surface area of a reactant

• Increasing the temperature

• Increasing the concentration of a reactant

• Increasing the concentration of an inhibitor

A container has 1.79 moles of H2 gas molecules. Which of the following correctly shows the denominator for the equation that will cancel out 1.79 moles of H2?

• 1 mol H2

• 2 g H2

• 1.79 mol H2

A student heats solid Iron (II) Oxide, Fe2O3 so that it decomposes according to the reaction below.

2 Fe2O3 (s) → 4 Fe (s) + 3 O2 (g)

The student measures the mass of the reactants before the reaction and the products after the reaction. Which of the following best explains why the total mass of Iron Oxide decreased?

• Oxygen is a gas, and particles of a gas have no mass.

• Oxygen is a gas, and the molecules of oxygen escaped into the air.

• Oxygen molecules were destroyed

• Iron particles were consumed and evaporated

The equation below shows the reaction between lead (II) nitrate (Pb(NO3)2) and potassium iodide (KI) to produce potassium nitrate (KNO3) and lead (II) iodide (PbI2).

Pb(NO3)2 (aq) + 2 KI (aq) → 2 KNO3 (aq) + PbI2 (s)

7 moles of KI are reacted with Pb(NO3)2. How many moles of PbI2 will be produced?

• 7 moles of PbI2

• 3.5 moles of PbI2

• 1.75 moles of PbI2

• 1 mole of PbI2

Predict the products that would be formed from this single replacement reaction. Cl2 (g) + MgBr2 (s) →

• MgCl2 and Br

• MgBr2 and Cl

• MgBr and ClBr

• MgCl2 and Br2

Which of the following correctly explains what happens to the rate of a chemical reaction when the surface area is increased?

• The rate of a chemical reaction increases because the additional exposed area allows for more reactant molecules to collide with each other.

• The rate of a chemical reaction decreases because the additional exposed area allows for fewer reactant molecules to collide with each other.

• The rate of a chemical reaction increases because there is an increase in the average kinetic energy

• The rate of a chemical reaction decreases because there is a decrease in the average kinetic energy

Which of the following sets of coefficients balances the equation below?

___Al (s) + ___HCl (aq) → ___ AlCl3 (aq) + ___ H2 (g)

• 1, 1, 1, 1

• 1, 3, 1, 3

• 2, 3, 2, 1

• 2, 6, 2, 3

Two containers contain equal masses of magnesium (Mg) and calcium (Ca), as shown below. Which container has the greater number of moles of the element and why?

• Container A, because magnesium (Mg) has a lower molar mass

• Container B, because calcium (Ca) has a greater molar mass.

• Container A, because the magnesium (Mg) sample has a fewer number of atoms.

• Container B, because the calcium (Ca) sample has a greater number of atoms

Identify the type of chemical reaction that is represented in the chemical equation below.

2BaO2 (s) → 2BaO (s) + O2 (g)

• Synthesis reaction

• Decomposition reaction

• Single replacement reaction

• Double replacement reaction