# 1.3 Reacting masses and volumes

### Stoichiometry

• Stoichiometry is the quantitative method of examining the relative amounts of reactants and products

### The limiting reagent

• Limiting reagent is completely consumed during a reaction, the remaining reactants are in excess
• The limiting reagent is what is used to determine the amount of products formed

### Percentage Yield

• Percentage yield is used to determine the efficiency of a reaction
• Some factors for where yield is lost include:
• Loss of products from reaction vessels
• Impurity of reactants
• Changes in reaction conditions, such as temperature and pressure
• Reverse reactions consuming products in equilibrium systems
• Existence of side reactions due to impurities

### Molar volume of a gas

• Ideal gas is a gas which follows the kinetic theory of gases. They are found in systems with high temperature and low pressure.
• Standard Temperature and Pressure (STP): The conditions where temperature is 273K and pressure is 100 kPa.
• At STP, the Molar Volume of an ideal gas is 22.7 dm3 mol-1
• Avogadro’s Law: Equal volumes of any gas measured at the same temperature and pressure contain the same number of molecules
• This can be applies to stoichiometric relationships in which the coefficients correspond to the ratio of volumes of gases

### The Gas Laws

1. Boyle’s Law
2. Charles’s Law
3. Gay-Lussac’s Law
4. Combined Gas Law
5. Ideal gas equation

### Titrations

• Titration involves a standard solution of known concentration which is added to a solution of unknown concentration until the chemical reaction is complete
• Watch this video