Unit 3 Part 2 Practice

A chemical reaction has the equation: 2A + B → C. Which of the following figures best illustrates a stoichiometric ratio of A to B?

• I only

• II only

• both I and IV

• both II and IV

Tags

NGSS.HS-PS1-7

The limiting reactant in a reaction:

• has the lowest coefficient in a balanced equation

• is the reactant for which you have the fewest number of moles

• has the lowest ratio of moles available/coefficient in the balanced equation

• has the lowest ratio of coefficient in the balanced equation/moles available

Phosphoric acid can be prepared by the reaction of sulfuric acid with phosphate rock according to the equation: Ca₃(PO₄)₂ + 3H₂SO₄ → 3CaSO₄ + 2H₃PO₄. Suppose the reaction is carried out starting with 3 moles of Ca₃(PO₄)₂ and 8 moles of H₂SO₄. Which substance is the limiting reactant?

• Ca₃(PO₄)₂

• H₂SO₄

• CaSO₄

• There is no limiting reactant. There are perfect amounts of both reactants to not have either one left over.

Tags

NGSS.HS-PS1-7

SO₂ reacts with H₂S as follows: 2H₂S + SO₂ → 3S + 2H₂O. When 7 moles of H₂S reacts with 4 moles of SO₂, which statement applies?

• 2 moles of H₂O is produced

• 3 moles of S is produced

• 10.5 moles of H₂O is produced

• 10.5 moles of S is produced

Tags

NGSS.HS-PS1-7

Given the equation 3A + B → C + D, you react 2 moles of A with 1 mole of B. Which of the following is true?

• A is the limiting reactant because of its higher molar mass

• A is the limiting reactant because you need 3 moles of A and have 2

• B is the limiting reactant because you have fewer moles of B than A

• B is the limiting reactant because 3 A molecules react with 1 B molecule

Tags

NGSS.HS-PS1-7

The limiting reactant in a reaction:

• is the reactant for which there is the least amount in grams

• is the reactant which has the lowest coefficient in a balanced equation

• is the reactant for which there is the most amount in grams

• is the reactant for which there is the fewest number of moles

• none of these

A chemical reaction has the equation 2A + B → C. In which case is B the limiting reactant?

• I

• II

• III

• IV

Tags

NGSS.HS-PS1-7

A chemical reaction has the equation 2A + B → C. In which case is there NO limiting reactant?

• I

• II

• III

• IV

Tags

NGSS.HS-PS1-7

You mixed two aqueous solutions together, expecting to see a precipitate form. Instead, after several minutes, you do not detect other visible changes. Which of the following is an observation for which you should have looked?

• gas bubbling

• heat evolving

• color change

• There are no other changes to look for because no reaction has occurred.

Aqueous solutions of sodium sulfate and barium chloride are combined. Which of the following setups would be appropriate to collect the product(s) of this reaction?

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