Confidence in Chemistry Calculations
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This course takes you through the essentials of mole calculations, formulae and amounts for all A Level chemistry syllabuses. Each module includes detailed examples and explanations, practice problems with video walkthroughs and self-assessment quizzes as well as the chance to ask questions on anything you’re stuck on!
Essential equations and formulae
This module gives an overview of most important types of reaction covered at GCSE (including combustion, precipitation, neutralisation and redox) and how they link to the three main types of equation: – full symbol equations, ionic equations and half equations. There are tips on how to balance different types of equation and how to construct the main examples for ionic and half equations.
Lessons
Video: chemical formulae Video: reaction types Video: ionic equations Video: redox and half equations Practice questions: reactions and equations Formulae and EquationsRelative atomic mass and formula mass
This module takes you through relative atomic mass calculations – from the easy to the more challenging examples including mass spectra of diatomic elements. It also goes through calculations of formula and molecular mass.
Lessons
Video: relative atomic mass calculations Practice questions: relative atomic mass Video: finding abundance from relative atomic mass Video: mass spectra of diatomic elements Practice questions: harder relative atomic mass calculations Video walkthrough: answers to harder practice questions Video: relative formula mass (Mr) calculations Practice questions: relative formula mass Self assessment quizMoles, Mr, empirical and molecular formulae
This module focuses on empirical formula, moles and molar mass including how we calculate empirical formula from experimental data.
Lessons
Video: moles and molar mass Practice questions: moles and molar mass Video: empirical and molecular formulae Practice questions: empirical and molecular formulae Video: calculations from experiments Practice questions: calculations from experiments Self assessment quizReacting mass, percentage yield and atom economy
Reacting mass questions are those that calculate the mass of a reactant or product using the mass of another substance in the equation. We will also look at limiting and excess reagents, percentage yield and atom economy.
Lessons
Video: using balanced equations Video: excess and limiting reagents Practice questions: balanced equations and reacting mass Video: percentage yield Video: atom economy Practice questions: percentage yield and atom economy Practice questions: harder examples for reacting mass VIdeo walkthrough: answers to harder examples Self assessment quizMolar volume and ideal gas calculations
Molar volume is the volume of one mole of gas under standard conditions – this module will look at how gas volume calculations differ from reacting mass calculations, as well as working through calculations using the ideal gas equation.
Lessons
Video: molar gas volume Practice questions: molar gas volume Video: ideal gas equation basics Video: applying the ideal gas equation Practice questions: ideal gas equation Self assessment quizSolutions and titration calculations
Avogadro, standard form and unit conversions
In this module we look at some important areas of calculations that can get missed out – working with Avogadro’s constant, converting between common units and also working with standard form, decimal places and significant figures.
Lessons
Video: moles and the Avogadro constant Video: common units and standard form Video: decimal places and significant figures Practice questions: units, Avogadro and standard form Self assessment quizLong answer problems and walkthroughs
In this module you get a change to practice more challenging calculations, which draw on skills from all the previous modules. All these examples have video walkthroughs so you can see where the marks are obtained. Remember to try the calculations first though without any help, as this is where you will get the most benefit.