Gases and Solutions

One mole of any gas occupies 24dm3 at 20c

• At the same temperature and pressure, equal number of moles of any gas will occupy the same volume
  • At room temperature and pressure one mole of any gas will occupy 24dm3
  • You can use this formula to find the volume of a known mass of any gas
  • Volume of gas = mass of gas / Mr of gas x 24

You can calculate volumes of gases in reactions

• For reactions between gases,you can use the volume of one gas to find the volume of another

Concentration is a measure of how crowded things are

• Lots of reactions in chemistry take place between substances that are dissolved in a a solution
• The amount of a substance in a certain volume of a solution is called its concentration
• The more solute there is in a given volume, the more concentrated the solution
• One way to measure the concentration of a solution is by calculating the mass of a substance in a given volume of solution
• The units will be units of mass/units of volume
  • Concentration = mass of solute / volume of solvent
  • Concentration = number of moles of solute / volume of solvent