2.6 Balanced equations, atom economies & percentage yields
Cards (19)
- Percentage atom economy is:Economic, ethical and environmental advantages for society and for industry of developing chemical processes with a high atom economy.
- A compound will be ionic if
- it contains a metal
- it's an acid in solution (will contain H+ ions)
- it's an ammonium salt (containing NH4+ ions)
- How do you know if an ion is positive or negative?
- All metals form positive ions
- Simple non-metals ions are negative
- What happens when an ionic compound dissolvesIons separate from eachother and become surrounded by solvent particles.
- Group 1 ions are soluble.
- Ammonium ion, NH4+ is soluble
- Nitrate ions NO3- are soluble
- All halide ions are soluble, except silver halides, AgX and lead (II) halides PbX2
- All sulfate ions are soluble, except barium sulfate, calcium sulfate and lead (II) sulfate
- All carbonates are insoluble, except sodium carbonate, potassium carbonate and ammonium carbonate
- All hydroxides are insoluble except sodium hydroxide and potassium hydroxide
- Remember than S.P.A.N. (sodium, potassium, ammonium or nitrate-containing) compounds are always soluble.
- Writing ionic equations
- Wrtie down the chemical equation including state symbols
- Rewrite by separating the soluble ionic compounds into their dissociated ions.
- Cancel out the spectator ions
- Write the net ionic equation
- A precipitate is a solid formed by the reaction of two aqueous solutions.
- Atom economy tells us how efficient a reaction is.% atom economy = (molecular mass of desired product / sum of Mr of all reactants) x 100
- Higher atom economies are used in industries
- Better for the environment
- Less waste to be disposed of
- Efficient use of raw materials so the process is sustainable
- Less expensive
- DO USE BALANCING NUMBERS WHEN CALCULATING % ATOM ECONOMY
- Percentage yield = (actual yield / theoretical yield) x 100
- Percentage yield = no. of moles of product obtained / theoretical max no. of moles