Unit#3: Stoichiometry

1

Mole is a unit related to:

A Mass B Volume C Number of particles D Density

2

Which formula is used for dilution?

A M = m/V B M₁V₁ = M₂V₂ C n = m/M D PV = nRT

3

Molarity decreases when:

A Solute is added B Solvent is removed C Solution is diluted D Temperature is lowered

4

One mole of any substance contains how many particles?

A 6.02 × 10^22 B 6.02 × 10^21 C 6.02 × 10^23 D 6.02 × 10^24

5

Which factor does NOT affect percentage yield?

A Side reactions B Purity of reactants C Balanced equation D Experimental loss

6

Which law is the basis of mole concept?

A Law of definite proportions B Law of conservation of mass C Avogadro’s law D Boyle’s law

7

Which quantity relates mass to moles?

A Atomic number B Molar mass C Density D Volume

8

If percentage yield is 100%, it means:

A No reaction occurred B Actual yield is zero C Actual yield equals theoretical yield D Loss of product occurred

9

Which of the following is used to prepare a dilute solution from a concentrated one?

A Evaporation B Distillation C Dilution D Filtration

10

What is the mass of one mole of carbon-12?

A 6 g B 12 g C 24 g D 1 g

11

The unit of molarity is:

A mol/kg B g/L C mol/L D g/mol

12

The amount of product formed depends on:

A Excess reactant B Limiting reactant C Temperature only D Pressure only

13

The mole ratio is valid only for:

A Unbalanced equations B Balanced equations C Word equations D Ionic equations

14

Dilution decreases:

A Moles of solute B Volume of solution C Concentration of solution D Mass of solute

15

The amount of substance is directly proportional to:

A Volume B Mass C Number of particles D Density

16

Mole ratio is obtained from which part of a chemical equation?

A Products only B Reactants only C Balanced coefficients D Chemical symbols

17

Which term refers to unused reactant left after reaction?

A Limiting reactant B Excess reactant C Product D Catalyst

18

Which concentration unit is affected by temperature?

A Strength B Molarity C Mass percent D Mole fraction

19

Which concentration unit depends on volume?

A Strength B Molarity C Mass percent D Mole fraction

20

Strength of solution changes with:

A Mass only B Volume only C Both mass and volume D Temperature only

21

Percentage yield can be greater than 100% if:

A Reaction is incomplete B Product is impure C Limiting reactant is less D No side reactions occur

22

Which term refers to the calculated amount of product?

A Actual yield B Percentage yield C Theoretical yield D Limiting yield

23

Which quantity is used to compare reactants in a balanced equation?

A Mass ratio B Volume ratio C Mole ratio D Density ratio

24

Dilution of a solution involves:

A Adding solute B Removing solute C Adding solvent D Heating solution

25

In the equation 2H₂ + O₂ → 2H₂O, the mole ratio of H₂ to O₂ is:

A 1:1 B 2:1 C 1:2 D 2:2