Concentration of solutions

• Moles = concentration ( mol/dm3 ) x volume ( dm3 )
• 0.2 moles of acid was dissolved in 100cm3 of water. Calculate the concentration

  Volume = 100cm3 ÷ 1000 = 0.1dm3

  Concentration = moles ÷ volume = 0.2 ÷0.1 = 2.0mol/dm3
• At room temperature ( 20°C ) and pressure ( 1 atmosphere ), the volume occupied by 1 mole of any gas is 24dm3.
• Number of moles of gas = volume of gas (dm3)/24dm3
• Find the volume that 2.5mol of nitrogen gas will occupy

  Volume = moles x 24 = 2.5 x 24 = 60.0dm3