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Concentrations - % w/w, %v/v, % w/v , ppm, M, g/L

• Concentrations indicate the amount of any substance disolved in a liquid.
  
  
• Square brackets, [ ], are often used as an abreviation for the term concentration.
  
  e.g. a 0.1 molar sodium hydroxide concentration can be refered to by [NaOH]=0.1M
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
• % w/w is an abbreviation for percentage weight of a substance of the total weight at a specified temperature-
  
  e.g. 10 % w/w H₂O₂ = 10 g hydrogen peroxide in 90 gm (90 ml) water.
  
  or 15 parts by weight of salt (NaCl) in 85 parts by weight of water (15% w/w) @ 12.5^oC was the original definition of 15^oBuame.
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
• %v/v is an abbreviation for percentage volume of a substance of the total volume -
  
  e.g. 12.5 % v/v ethanol. = 12.5 ml ethanol in approx. 87.5 ml water -
  
  Alcohol concentration is stated as ethanol as it is the predominant alcohol in wine (see ethanol equivalents)
  
  often seen on wine labels as 12.5 % Alc.or 12.5 ALC/VOL or ALCOHOL 12.5% BY VOLUME (note the predominate alcohol in wine is ethanol)
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
• % w/v is an abbreviation for percentage weight of a substance of the total volume -
  
  e.g. 18% w/v orthophosporic acid (H₂PO₄) = 18 g H₂PO₄ in a total volume of 100 ml of solution -
  
  i.e. 18 g H₂PO₄ dissolved in water and topped up with water to the 100ml mark in a 100 ml volumetric flask.
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  ( ppm, mg/L )
  
  
  • ppm is an abbreviation for parts per million and is the equivelent to mg/L (more)
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
  • g/L is an abbreviation for grams per litre, and are the units used to record wine acidity concentrations.