Concentration

• Concentration tells us the mass of a solute in a given volume of solution
• A solute is a chemical that is dissolved in a solvent
• In chemistry , water is often used as a solvent
• dm³ is what used to be called a litre but scientists don't use that word anymore
• Concentration is measured in g/dm³ or mol/dm³
• To convert cm³ into dm³ , divide by 1000
• To convert from dm³ to cm³ , multiply by 1000
• Remember that 1000 cm³ = 1 dm³
• Equation for concentration using mass

  Concentration (g/dm³) = mass of substance (g) / volume (dm³)
• Equation for concentration using amount?

  Concentration (mol/dm³) = amount of substance (mol) / volume (dm³)
• 200g of a chemical is dissolved in water , to a final volume of 1dm³. Calculate the concentration of the solution?

  Concentration = 200 g/dm³
• 150g of a chemical is dissolved in water to a final volume of 0.5 dm³. Calculate the concentration of the solution?

  Concentration = 300 g/dm³
• Calculate the mass of a chemical needed to dissolve in a final volume of 0.4 dm³ to give a final concentration of 600 g/dm³

  Mass = 240g
• Calculate the final volume of a solution containing 200g of a chemical with a concentration of 800g

  Volume = 0.25 dm³
• • If we increase the mass of solute and keep the volume the same , then we increase the concentration 
  • If we keep the mass the same and increase the volume of solution , then we decrease the concentration