Page 1: Amount of Substance Calculations

This page covers fundamental A Level Chemistry Amount of Substance equations and calculations essential for understanding stoichiometry and chemical reactions.

The page begins by introducing key equations for calculating moles, including the relationship between moles, mass, and relative molecular mass (Mr). It also presents the equation for calculating moles using volume and concentration.

Definition: Moles represent the amount of substance and can be calculated using mass, volume, or concentration.

The page then delves into more complex calculations, including determining empirical formulas, which represent the simplest whole number ratio of atoms in a compound.

Example: For potassium carbonate (K₂CO₃), the empirical formula is determined by finding the ratio of moles of each element.

The concept of water of crystallization is introduced, using magnesium sulfate (MgSO₄·xH₂O) as an example. Students learn how to calculate the number of water molecules (x) in hydrated compounds.

Highlight: Understanding water of crystallization is crucial for accurately representing hydrated compounds in chemical formulas.

The page also covers calculations involving gases at room temperature and pressure (RTP), introducing the ideal gas law (PV = nRT) and its applications.

Vocabulary: RTP refers to standard conditions where temperature is 25°C (298K) and pressure is 101 kPa.

Finally, the page explains percentage yield and atom economy calculations, which are important for assessing the efficiency of chemical reactions.

Example: Percentage yield is calculated by dividing the actual amount of product by the theoretical amount and multiplying by 100.