Grab binders, handouts, returned work & calculators, begin the Do Now5/16 DO NOW

1. Determine how many moles of H2O you would have if you were given 16g of H2O.

2. Determine how many grams of NaBr you would have if you were given 3 moles of NaBr.

3. Balance the following reaction:___Cu + ___H2SO4 ___Cu2SO4 + ___H2

Mandatory Office Hours by MON 5/20P1

Josh ADavid ANicholasRubenJuanKishaAntwanDajonLeeCiera

P3DarrionMariaWilliamDelanteKarinaBradleyJacquesLeandreaMonica

G4DoneikaKhariPerlaLa’NeshaArturoMilton

G5AdalynnArkitaTianaAngelJoeyRavenBobDeyja

Stoichiometry Part I RecapMolar Mass = sum of mass #’s of all elements in a compound (g/mol)

Moles Mass = moles x Molar Mass

Mass Moles = grams ÷ Molar Mass

Stoichiometry Part II NotesKey Point #1:To convert between moles X & moles Y =

MULTIPLY Moles reactant by MOLAR RATIO

Molar Ratio = coefficients of balanced reaction

Moles MolesExample 1:

2H2O2(aq) 2H2O(l) + O2(g)

1. What is the molar ratio between H2O2 and O2?

2. If you start with 4 moles of H2O2, how many moles of O2 will you produce?

3. If you start with 8 moles of H2O2, how many moles of H2O will you produce?

Moles MolesExample 2:

2H2 + O2 2H2O

1. What is the H2 / H2O mole ratio?

2. If you had 30 moles of H2, how many moles of H2O could you make?

3. If you had 3 moles of H2O, how many moles of O2 reacted?

Moles MolesExample 3:

N2(g) + 2CO2(g) 2CN(g) + 2O2(g)

1. What is the mole ratio between CO2 and O2?

2. If you start with 3 moles of CO2, how many moles of O2 will you produce?

3. If you start with 5 moles of N2, how many moles of CN will you produce?

Stoichiometry Part II NotesKey Point #2:Steps to Climb the Mole Hill1. Calculate the Molar Masses for the given and

unknown 2. Convert given mass to moles3. Convert moles of given to moles of unknown4. Convert moles of unknown to mass of

unknown

Climbing the Mole HillExample 1:

2H2O2(aq) 2H2O(l) + O2(g)

1. If you start with 6 grams of H2O2, how many grams of O2 will you produce?

Climbing the Mole HillExample 2:

2H2O2(aq) 2H2O(l) + O2(g)

2. If you produce 36 grams of H2O, how many grams of H2O2 did you start with?

Climbing the Mole HillExample 3:

2NaCl(aq) + Pb(NO3)2(aq) 2NaNO3(aq) + PbCl2(s)

3. If you produce 30g of PbCl2, how many grams of NaCl did you use?

Stoichiometry Debrief

Conversion Factors:Molar MassMolar Ratio

Keep track of your UNITS & COMPOUNDS!

Lab 2: Biodegradable SoapQuestion: determining this using pH

Are natural, homemade soaps better or worse for our skin compared to generically mass-produced

soaps?

Lab 2: Biodegradable Soap Data

pH Scale:

Soap Brand pH

Lever 9

Irish Spring 9.5

Dove 7

Homemade

Lab 2, Part 2 Directions:

1. Collect your lab group’s soap samples

2. Weigh the mass of ALL of your soap samples on an electronic balance. Record the total mass in your lab 2 data section!

3. Tear a small piece of soap from one of your samples and place into a clean test tube.

4. Fill the test tube ¾ of the way with water

5. Place your thumb over the open end of the test tube and shake vigorously to dissolve the soap

6. Dip one end of the pH strip into the soap solution. Allow the pH strip to dry completely (blow on it to help dry)

7. Use the pH scale located in the hood to assess your soap’s pH level. Record the pH of your soap in you lab 2 data section!

Lab 2: Biodegradable SoapClean Up:- Empty soap solution down the sink- Throw out used pH strips- Collect your lab group’s soaps in a Zip Lock Bag

from Ms. Herndon at the front desk. - Begin Post-lab Questions & Conclusion

Exit Ticket 6Directions:

You have 10 minutes to complete the Exit Ticket to the best of your ability. You MAY NOT use notes, but you may use a Periodic Table. When finished submit to the class bucket.