quantitive chemcical reactions gcse aqa Flashcards
What is a quantitative chemical reaction?
A reaction that involves measuring the amounts of reactants and products.
True or False: The law of conservation of mass states that mass is created in a chemical reaction.
False
What is the formula for calculating moles?
Moles = Mass (g) / Molar Mass (g/mol)
Fill in the blank: The molar mass of water (H2O) is ____ g/mol.
18
How do you calculate the mass of a reactant needed for a reaction?
Mass = Moles × Molar Mass
What is the role of a balanced chemical equation in quantitative reactions?
It shows the ratio of moles of reactants to products.
What does the term ‘yield’ refer to in a chemical reaction?
The amount of product obtained from a reaction.
What is the ideal yield in a chemical reaction?
Theoretical yield calculated from the balanced equation.
True or False: Actual yield is always equal to theoretical yield.
False
What is percentage yield?
Percentage yield = (Actual yield / Theoretical yield) × 100%
What is the molar volume of a gas at room temperature and pressure (RTP)?
24 dm³/mol
Fill in the blank: One mole of any gas occupies ____ dm³ at RTP.
24
What is the term for the smallest whole number ratio of moles in a reaction?
Stoichiometry
How do you find the limiting reactant in a reaction?
By calculating the moles of each reactant and determining which one runs out first.
What is the balanced equation for the reaction between hydrogen and oxygen to produce water?
2H₂ + O₂ → 2H₂O
What is the significance of the coefficients in a balanced equation?
They represent the number of moles of each substance involved.
True or False: Increasing temperature generally increases the rate of a chemical reaction.
True
What is the effect of concentration on the rate of reaction?
Higher concentration increases the rate of reaction.
What is meant by ‘excess reagent’?
A reactant that remains after the reaction has gone to completion.
Fill in the blank: The molar mass of carbon dioxide (CO2) is ____ g/mol.
44
What is the formula to calculate the number of moles of a gas?
Moles = Volume (dm³) / Molar Volume (24 dm³/mol)
What does a reaction yield of 50% indicate?
The actual yield is half of the theoretical yield.
How do you convert grams of a substance to moles?
Divide the mass in grams by the molar mass.
What is the formula for calculating the mass of product formed in a reaction?
Mass of product = (Moles of reactant used) × (Molar mass of product)
True or False: Stoichiometric calculations are based on the balanced equation.
True
What is the term for a reaction that goes to completion?
Irreversible reaction
Fill in the blank: The limiting reactant determines the ____ of the reaction.
amount of product formed
What is the significance of the term ‘molarity’?
It measures the concentration of a solution in moles per liter.
What is the unit of molarity?
moles per liter (mol/L)
How do you calculate the concentration of a solution?
Concentration = Moles of solute / Volume of solution (L)
What does it mean if a reaction has a high percentage yield?
It indicates that most of the reactants were converted into products.
What is the purpose of titration in quantitative chemistry?
To determine the concentration of a solution.
What is the relationship between moles and volume for gases at RTP?
1 mole of gas occupies 24 dm³ at RTP.
Fill in the blank: The molar mass of sodium chloride (NaCl) is ____ g/mol.
58.5
What is the first step in performing a stoichiometric calculation?
Write and balance the chemical equation.
True or False: The coefficients in a balanced equation can be fractional.
False
What is the term for a reaction that can proceed in both directions?
Reversible reaction
