Using concentration of solutions

• Concentration


  The mass of a solute in a given volume of solution
• Concentration in moles per decimeter cubed

  The number of moles of solute divided by the volume in decimeters cubed
• Calculating concentration in moles per decimeter cubed

  Number of moles / Volume in decimeters cubed
• Typical question


  • Solution has a concentration of 0.5 moles per decimeter cubed, calculate the number of moles in 0.2 decimeters cubed
• Calculating number of moles

  Concentration x Volume
• Typical question


  • Solution has a concentration of 0.2 moles per decimeter cubed, calculate the number of moles in 1.5 decimeters cubed
• Calculating mass of solute

  Number of moles x Relative formula mass
• Typical question


  • Solution of calcium chloride has a concentration of 0.4 moles per decimeter cubed, calculate the mass in 2 decimeters cubed (relative formula mass of calcium chloride is 111)
• Typical question


  • Solution of sodium nitrate has a concentration of 0.8 moles per decimeter cubed, calculate the mass in 0.5 decimeters cubed (relative formula mass of sodium nitrate is 85)
• Calculating concentration of a solution


  1. Write C=N/V equations

  2. Substitute given values

  3. Calculate number of moles

  4. Use mole ratio to find other moles

  5. Divide moles by volume to get concentration
• Concentration


  Moles per unit volume
• Moles


  Amount of substance
• 1 mol of reactant A reacts with 1 mol of reactant B
• Moles of A = Moles of B in a reaction
• Concentration = Moles / Volume