Chapter 3: Stoichometry/Mass Balence

what is equation for Percent Yield?

(Actual yield off product)/(theoretical yield of product) x 100%

How do you convert Mass to Moles?

(mass of compound) x (1 mole/(molar mass of compound)) = mole of compound

Calculate molecular weight of C2H4?

28.0 Work: 2C = (2)(12) = 24 4H = (4)(1) = 4 24+4 = 28

Example: 2NaOH + Cl2 = NaOCl + NaCl +H2O How many grams of NaOH is needed to react with 25 grams of Cl2?

28.2 grams NaOH Work: 1. Convert grams Cl2 to moles Cl2. Find Cl2 Molar Mass! Cl2 molar mass: 70.9 (25 g Cl2) x (1 mole Cl2/70.9 g Cl2) = 0.353 mol Cl2 2. Convert moles Cl2 to moles NaOH (0.353 mol Cl2) x (2 mol NaOH/1 mol Cl2) = .706 mol NaOH 3. convert moles of NaOH to grams. Find molar mass of NaOH. NaOH molar mass: 40 grams/mol (.707 mol NaOH) x (40 grams NaOH/1 mol NaOH) = 28.2

Balance Following Equation: NH3 + O2 = NO + H2O

4NH3 + 5O2 = 4NO + 6H2O

What is avagadros number?

6.02 x 10^23

What is law of mass conservation?

Atoms cannot be created nor destroyed in a chemical reaction.

Balance Following Equation: C3H8 + O2 = CO2 + H2O

C3H8 + 5O2 = 3CO2 + 4H2O

What is molecular weight?

Sum of atomic weight of all atoms in molecule