AQA A-Level Chemistry 7405
Atomic Structure
Amount of Substance
Bonding
Energetics and Thermodynamics
Kinetics
Chemical Equilibria
Redox and Electrochemistry
Acids and Bases
Periodicity and Group Chemistry
Period 3 Elements and Their Oxides
Transition Metals
Introduction to Organic Chemistry
Hydrocarbons
Halogenoalkanes, Alcohols and Organic Analysis
Carbonyls, Carboxylic Acids and Derivatives
Aromatic Chemistry and Amines
Polymers, Amino Acids, Proteins and DNA
Organic Synthesis, NMR and Chromatography
Amount of Substance
Balanced Equations and Reaction Calculations
- 3 things to know
- Papers 1, 2 and 3
Overview
Balancing equations and using the ratios in them to work out reacting masses.
What you need to know
Answer each one before you reveal it.
What must be conserved in a balanced chemical equation?
In terms of atoms, what does balancing a chemical equation ensure?
Questions from this subtopic
Each one with the model answer underneath.
- 1
What must be conserved in a balanced chemical equation?
Model answer
Mass and the number of atoms of each element on both sides of the equation
- 2
In terms of atoms, what does balancing a chemical equation ensure?
Model answer
The same number of atoms of each element appears on both sides
- 3
What is the relationship between the coefficients in a balanced equation and the molar ratios of reactants and products?
Model answer
The coefficients represent the ratio of moles in which substances react and are produced
- 4
How can the mass of a product be calculated from a balanced equation and the mass of a reactant?
Model answer
Convert mass of reactant to moles, use the molar ratio to find moles of product, then convert moles of product to mass
- 5
What is the first step when calculating the mass of product formed from a given mass of reactant?
Model answer
Convert the mass of reactant to moles using moles = mass ÷ molar mass
- 6
After finding the moles of reactant, how do you determine the moles of product formed?
Model answer
Use the molar ratio from the balanced equation to convert moles of reactant to moles of product
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