quantitive chemcical reactions gcse aqa

Question 1

What is a quantitative chemical reaction?

Answer 1

A reaction that involves measuring the amounts of reactants and products.

Question 2

True or False: The law of conservation of mass states that mass is created in a chemical reaction.

Answer 2

False

Question 3

What is the formula for calculating moles?

Answer 3

Moles = Mass (g) / Molar Mass (g/mol)

Question 4

Fill in the blank: The molar mass of water (H2O) is ____ g/mol.

Answer 4

18

Question 5

How do you calculate the mass of a reactant needed for a reaction?

Answer 5

Mass = Moles × Molar Mass

Question 6

What is the role of a balanced chemical equation in quantitative reactions?

Answer 6

It shows the ratio of moles of reactants to products.

Question 7

What does the term ‘yield’ refer to in a chemical reaction?

Answer 7

The amount of product obtained from a reaction.

Question 8

What is the ideal yield in a chemical reaction?

Answer 8

Theoretical yield calculated from the balanced equation.

Question 9

True or False: Actual yield is always equal to theoretical yield.

Answer 9

False

Question 10

What is percentage yield?

Answer 10

Percentage yield = (Actual yield / Theoretical yield) × 100%

Question 11

What is the molar volume of a gas at room temperature and pressure (RTP)?

Answer 11

24 dm³/mol

Question 12

Fill in the blank: One mole of any gas occupies ____ dm³ at RTP.

Answer 12

24

Question 13

What is the term for the smallest whole number ratio of moles in a reaction?

Answer 13

Stoichiometry

Question 14

How do you find the limiting reactant in a reaction?

Answer 14

By calculating the moles of each reactant and determining which one runs out first.

Question 15

What is the balanced equation for the reaction between hydrogen and oxygen to produce water?

Answer 15

2H₂ + O₂ → 2H₂O

Question 16

What is the significance of the coefficients in a balanced equation?

Answer 16

They represent the number of moles of each substance involved.

Question 17

True or False: Increasing temperature generally increases the rate of a chemical reaction.

Answer 17

True

Question 18

What is the effect of concentration on the rate of reaction?

Answer 18

Higher concentration increases the rate of reaction.

Question 19

What is meant by ‘excess reagent’?

Answer 19

A reactant that remains after the reaction has gone to completion.

Question 20

Fill in the blank: The molar mass of carbon dioxide (CO2) is ____ g/mol.

Answer 20

44

Question 21

What is the formula to calculate the number of moles of a gas?

Answer 21

Moles = Volume (dm³) / Molar Volume (24 dm³/mol)

Question 22

What does a reaction yield of 50% indicate?

Answer 22

The actual yield is half of the theoretical yield.

Question 23

How do you convert grams of a substance to moles?

Answer 23

Divide the mass in grams by the molar mass.

Question 24

What is the formula for calculating the mass of product formed in a reaction?

Answer 24

Mass of product = (Moles of reactant used) × (Molar mass of product)

Question 25

True or False: Stoichiometric calculations are based on the balanced equation.

Answer 25

True

Question 26

What is the term for a reaction that goes to completion?

Answer 26

Irreversible reaction

Question 27

Fill in the blank: The limiting reactant determines the ____ of the reaction.

Answer 27

amount of product formed

Question 28

What is the significance of the term 'molarity'?

Answer 28

It measures the concentration of a solution in moles per liter.

Question 29

What is the unit of molarity?

Answer 29

moles per liter (mol/L)

Question 30

How do you calculate the concentration of a solution?

Answer 30

Concentration = Moles of solute / Volume of solution (L)

Question 31

What does it mean if a reaction has a high percentage yield?

Answer 31

It indicates that most of the reactants were converted into products.

Question 32

What is the purpose of titration in quantitative chemistry?

Answer 32

To determine the concentration of a solution.

Question 33

What is the relationship between moles and volume for gases at RTP?

Answer 33

1 mole of gas occupies 24 dm³ at RTP.

Question 34

Fill in the blank: The molar mass of sodium chloride (NaCl) is ____ g/mol.

Answer 34

58.5

Question 35

What is the first step in performing a stoichiometric calculation?

Answer 35

Write and balance the chemical equation.

Question 36

True or False: The coefficients in a balanced equation can be fractional.

Answer 36

False

Question 37

What is the term for a reaction that can proceed in both directions?

Answer 37

Reversible reaction