2 A. Proportional Relationships 2 1/4 c. flour1 tsp. baking soda1 tsp. salt1 c. butter3/4 c. sugar3/4 c. brown sugar1 tsp vanilla extract2 eggs2 c. chocolate chipsMakes 5 dozen cookies.I have 5 eggs. How many cookies can I make?Ratio of eggs to cookies5 eggs5 doz.2 eggs= 12.5 dozen cookies
3 A. Proportional Relationships Stoichiometrymass relationships between substances in a chemical reactionbased on the mole ratioMole Ratioindicated by coefficients in a balanced equation2 Mg + O2 2 MgO
4 B. Stoichiometry Steps 1. Write a balanced equation. 2. Identify known & unknown.3. Line up conversion factors.Mole ratio - moles molesMolar mass - moles gramsMolarity - moles liters solnMolar volume - moles liters gasMole ratio - moles molesCore step in all stoichiometry problems!!4. Check answer.
5 Standard Temperature & Pressure C. Molar Volume at STP1 mol of a gas=22.4 Lat STPStandard Temperature & Pressure0°C and 1 atm
6 C. Molar Volume at STP LITERS OF GAS AT STP Molar Volume MASS IN GRAMS (22.4 L/mol)MASSINGRAMSMOLESNUMBEROFPARTICLESMolar Mass(g/mol)6.02 1023particles/molMolarity (mol/L)LITERSOFSOLUTION
7 D. Stoichiometry Problems How many moles of KClO3 must decompose in order to produce 9 moles of oxygen gas?2KClO3 2KCl + 3O2? mol9 mol9 mol O22 mol KClO33 mol O2= 6 molKClO3
8 D. Stoichiometry Problems How many grams of KClO3 are req’d to produce 9.00 L of O2 at STP?2KClO3 2KCl + 3O2? g9.00 L9.00 LO21 molO222.4 L2 molKClO33 molO2122.55g KClO31 molKClO3= 32.8 gKClO3
9 D. Stoichiometry Problems How many grams of silver will be formed from 12.0 g copper reacting with silver nitrate?Cu + 2AgNO3 2Ag + Cu(NO3)212.0 g? g12.0g Cu1 molCu63.55g Cu2 molAg1 molCu107.87g Ag1 molAg= 40.7 gAg
10 D. Stoichiometry Problems How many grams of Cu are required to react with 1.5 L of 0.10M AgNO3?Cu + 2AgNO3 2Ag + Cu(NO3)2? g1.5L0.10M1.5L.10 molAgNO31 L1 molCu2 molAgNO363.55g Cu1 molCu= 4.8 gCu
12 D. Stoichiometry Problems Work on Handout – “Mole-Mole Problems”
13 D. Stoichiometry Problems – Mole/Mass In photosynthesis, carbon dioxide and water react to form glucose, C6H12O6 and oxygen gas.___CO2 + ___H2O ___C6H12O6 + ___O2If 15.6 grams of carbon dioxide react, how many moles of glucose will be produced?How many grams of carbon dioxide must react to produce 0.25 moles of glucose?66615.6 g CO21 mol CO21 mol C2 H12O6= mol C2H12O644.01 g CO26 mol CO20.25 mol C2 H12O66 mol CO244.01 g CO2= 66 g CO21 mol C2 H12O61 mol CO2
14 D. Stoichiometry Problems Work on Handout – “Mole-Mass Problems”
15 D. Stoichiometry Problems – Mass/Mass Sodium metal reacts with oxygen gas to produce solid sodium oxide. How many grams of sodium must react to produce 42.0 grams of sodium oxide?4Na + O2 2Na2O? g42.0 g42.0g Na2O1 molNa2O22.99g Na4 mol Na= 22.99g Na16.98g Na2O1 mol Na2 molNa2O
16 D. Stoichiometry Problems Work on Handout – “Mass-Mass Problems”
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