Chemistry I Chapter 9 Review Actual yield = amount of product that is recovered Excess reactant = reactant that remains when reaction ends Limiting reactant = reactant that runs out first Percent yield = comparison of predicted and actual amounts of product Chemistry I Chapter 9 Review Stoichiometry = calculation of quantities in chemical reactions Theoretical yield = predicted amount of product * Mass and atoms are conserved in a chemical reaction. (why we have to balance equations!) Chemistry I Chapter 9 Review Actual yield = amount from experiment Theoretical = CALCULATED AMOUNT!!!! Mole ratio (mol over mol) – use the coefficients Always convert the first component from grams to moles. Balance - Al + CuSO4 Al2(SO4)3 + Cu Interpret the equation for atoms and moles. Chemistry I Chapter 9 Review If 0.5moles of Al(NO3)3 are used up in the following reaction, how many moles of HNO3 will be produced? Al(NO3)3 + H2SO4 Al2(SO4)3 + HNO3 Balance first then solve for 0.5mol. Chemistry I Chapter 9 Review If 50g of iron react with oxygen gas to produce iron(III)oxide, how many moles of oxygen gas will be needed? 1-write equation 2-balance equation 3-change 50 to moles 4-use mole ratio Chemistry I Chapter 9 Review Zinc sulfide reacts with oxygen gas to form zinc oxide and sulfur dioxide. If 2moles of ZnS are combined with 3 moles of O2, how many moles of ZnO can be produced? How many moles of the excess reactant will be left over? 1- write and balance equation 2- do each reactant separately 3- the lesser mole amount “wins” (is the answer) 4-to find how much excess, calc and sub from original starting moles. Chemistry I Chapter 9 Review Solid iron reacts with hydrochloric acid to form iron(II)chloride and hydrogen gas. What mass of FeCl2 could be produced from 70g of Fe and excess of HCl? 1-write and balance equation 2-change 70g to moles 3-use mole/mole ratio (and coefficients) 4-change moles back to grams Chemistry I Chapter 9 Review Magnesium carbonate decomposes into magnesium oxide and carbon dioxide. If 23.4g of MgO is produced from 59.6g of MgCO3, what is the percent yield? 1-write and balance equation 2-change g to mole 3-use mole / mole ratio 4-change moles back to grams 5-%yield = actual divided by theoretical times 100