BMST Chemical Reactions and Stoichiometry 5

Question 1

In a single replacement reaction, what determines whether the reaction will occur?

Accepted Answer

Whether the replacing element is more reactive than the one it displaces

Answer

A single replacement reaction occurs only if the replacing element is higher on the activity series than the element it displaces.

Question 2

What is theoretical yield?

Accepted Answer

The maximum amount of product calculated from stoichiometry assuming complete reaction

Answer

Theoretical yield is the calculated maximum product possible based on the limiting reagent and stoichiometry.

Question 3

Which equation is correctly balanced?

Accepted Answer

2H₂ + O₂ → 2H₂O

Answer

2H₂ + O₂ → 2H₂O has 4 hydrogen atoms and 2 oxygen atoms on each side, satisfying conservation of mass.

Question 4

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 ÷ liters = 2 mol ÷ 0.5 L = 4 M.

Question 5

In the reaction 2Al + 3Cl₂ → 2AlCl₃, if 3 moles of Cl₂ are available and 4 moles of Al are available, which is the limiting reagent?

Accepted Answer

Cl₂, because it requires a 3:2 ratio with Al and runs out first

Answer

3 moles Cl₂ can react with only 2 moles Al (ratio 3:2), leaving 2 moles Al unused; Cl₂ is the limiting reagent.

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