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Chemistry 11. Stoichiometry Mass Gets Involved. Why Does Mass Get Involved?. When determining quantities that react and form in a chemical reaction, it is important to remember this:
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Chemistry 11 Stoichiometry Mass Gets Involved
Why Does Mass Get Involved? When determining quantities that react and form in a chemical reaction, it is important to remember this: • In a practical setting, like a laboratory a chemist measures mass, volume or some other quantity, never moles. • There is no scale that measures moles. • Chemists can measure mass, solution volume, gas volume…and convert them to moles using unitary rates (mole conversions).
A Sample Stoichiometry Question: • 15.00 grams of Aluminum reacts with excess Copper (II) chloride, determine the theoretical yield (in grams) of Copper solid that forms. • Each stoichiometry question is answered using a simple 4 step strategy. The 4 steps never change, only the numbers and the equations will change.
Stoichiometry Solution Strategies • Step 1: BRE Write the balanced chemical reaction equation.
Stoichiometry Solution Strategies • Step 1: BRE Write the balanced chemical reaction equation. 2 Al(s) + 3 CuCl2(aq)3 Cu(s) + 2 AlCl3(aq)
Stoichiometry Solution Strategies • Step 2: MC1 Determine the moles of the given substance, using the mole conversions.
Stoichiometry Solution Strategies • Step 2: MC1 Determine the moles of the given substance, using the mole conversions.
Stoichiometry Solution Strategies • Step 3: MR Use a mole ratio to determine the moles of the unknown substance.
Stoichiometry Solution Strategies • Step 3: MR Use a mole ratio to determine the moles of the unknown substance.
Stoichiometry Solution Strategies • Step 4: MC2 Use the mole conversions to translate moles of unknown to the desired quantities.
Stoichiometry Solution Strategies • Step 4: MC2 Use the mole conversions to translate moles of unknown to the desired quantities.