BMST - Basic Math and Science Chemical Reactions and Stoichiometry Questions and Answers 5

Question 1

Which of the following describes an exothermic reaction?

Accepted Answer

Energy is released to the surroundings

Answer

Exothermic reactions release energy to the surroundings, making the products lower in energy than the reactants.

Question 2

When balancing the equation __Fe + __O₂ → __Fe₂O₃, what are the correct coefficients?

Accepted Answer

4, 3, 2

Answer

The balanced equation is 4Fe + 3O₂ → 2Fe₂O₃, conserving iron (4 atoms each side) and oxygen (6 atoms each side).

Question 3

What is the molarity of a solution containing 2 moles of NaCl dissolved in 0.5 liters of solution?

Accepted Answer

4 M

Answer

Molarity = moles of solute / liters of solution = 2 mol / 0.5 L = 4 M.

Question 4

In a single replacement reaction, Zn + CuSO₄ → ZnSO₄ + Cu, what is the driving force?

Accepted Answer

Zinc is more reactive than copper and displaces it

Answer

Zinc is higher on the activity series than copper, so it displaces copper from the solution.

Question 5

If 2 moles of H₂ react with 1 mole of O₂ to form water, and you start with 3 moles of H₂ and 1 mole of O₂, which is the limiting reagent?

Accepted Answer

O₂

Answer

O₂ is the limiting reagent because 1 mol O₂ can only react with 2 mol H₂, leaving 1 mol H₂ unused.

BMST - Basic Math and Science Test Practice Test