Chemistry (4/25)

1
Chemistry (4/25)

• Objectives
• Complete Chemical Quantities Exam
• Perform Hydrate Lab
• Homework
• Answer post lab questions.

2
Chemistry (4/26)

• Objectives
• Complete Hydrate Lab and post-lab questions.
• Homework
• Complete post lab questions. Due Monday

3
Chemistry (4/29)

• Objectives
• Complete post-lab questions for Hydrate Lab.
• Identify and apply stoichiometry with substances
  in a chemical equation.
• Homework
• Stoichiometry Problems

4
Hydrate Lab

• Cu(SO4) . H2O ----gt Cu(SO4) H2O
• Post-Lab questions
• Use the equation above to help answer the
  following questions
• What was the hydrate salt in this experiment?
• What was the anhydrous salt in this experiment?
• What was the difference between the hydrated salt
  and the anhydrous salt in this experiment?
• Was this a physical or chemical reaction?
  Validate your answer with data from your lab.

5
Hydrate Lab

• Cu(SO4) . H2O ----gt Cu(SO4) H2O

6
Copper Sulfate Hydrate
7
What is Stoichiometry?
access.aasd.k12.wi.us
8
Stoichiometry

• N2 3H2
  ----------gt 2NH3

(NH3 ) (N2)
www.larapedia.com
9
Chemistry (5/1)

• Infinite Campus Update
• Chemical Quantities Exam (37pts)
• Hydrate Lab (10pts.)
• Objectives
• Identify and apply stoichiometry with substances
  in a balanced chemical equation.
• Homework
• Stoichiometry Problems

10
Bell Ringer

• Calculate the percent composition of water in
  this hydrate Mg(SO4) . 7H2O (Epsom Salt)
• What is stoichiometry?
• 3. N2H4 O2 -----gt N2
  H2O
• a. Balance the chemical equation.
• b. How many moles of rocket fuel (N2H4) are
  needed to produce 8 moles of N2?

11
Bell Ringer

• Calculate the percent composition of water in
  this hydrate Mg(SO4) . 7H2O (Epsom Salt)
• 2.What is stoichiometry?
• 3. N2H4 O2 -----gt N2
  H2O
• a. Balance the chemical equation.
• b. How many moles of rocket fuel (N2H4) are
  needed to produce 8 moles of N2?

12
Bell Ringer

• Calculate the percent composition of water in
  this hydrate Mg(SO4) . 7H2O (Epsom Salt)
• What is stoichiometry?
• 3. N2H4 O2 -----gt N2
  H2O
• a. Balance the chemical equation.
• b. How many moles of rocket fuel (N2H4) are
  needed to produce 8 moles of N2?

13
Stoichiometry

• N2 3H2
  ----------gt 2NH3
• Stoichiometry
• Converting between substances in a balanced
  chemical equation using mole conversions.

(NH3)
(N2)
www.larapedia.com
14
Stoichiometry

• H2O ----------gt H2
  O2
• What type of reaction is this?
• Balance the chemical equation if needed.
• If you start with 100 moles of H2O how many moles
  of H2 would be produced?
• If you want to produce 3.8moles of O2, how much
  H2O will you need to start with?

15
Chemistry (5/2)

• Objectives
• Identify and apply stoichiometry with substances
  in a balanced chemical equation.
• Homework
• Stoichiometry Problems

16
Stoichiometry Mole to Mole
17
Stoichiometry

• N2 3H2
  ----------gt 2NH3
• Stoichiometry
• Converting between substances in a balanced
  chemical equation using mole conversions.

www.larapedia.com
18
Stoichiometry Problems

• N2H4 O2 -----gt N2 2
  H2O
• If 13.8 grams of water were produced how much
  rocket fuel (N2H4) in grams would have been used
  up?

19
Chemistry (5/6)

• Objectives
• Identify and apply stoichiometry with substances
  in a balanced chemical equation.
• Homework
• Stoichiometry Problems (due Wed.)
• Gas Laws Graphing Assignment (due Wed.)
• Quiz Wednesday (Stoichiometry conversions
  mole to mole or grams to grams.)

20
Stoichiometry

• N2 3H2
  ----------gt 2NH3
• Stoichiometry
• Converting between substances in a balanced
  chemical equation using mole conversions.

www.larapedia.com
21
Stoichiometery Problems
22
Pre-AP Chemistry (4/25)

• Objectives
• Apply stoichiometry conversions with substances
  in chemical equations.
• Identify and apply limiting reactants in chemical
  reactions.
• Calculate Stoichiometry
• Homework
• Stoichiometry and Limiting Reactants

23
Stoichiometry

• N2 3H2
  ----------gt 2NH3
• Stoichiometry
• Converting between substances in a balanced
  chemical equation using mole conversions.

www.larapedia.com
24
Stoichiometry Limiting Reactants

• Limiting Reactant
• Excess Reactant

en.wikipedia.org
25
Stoichiometry Limiting Reactants

• Limiting Reactant completely consumed
• Excess Reactant partially consumed

en.wikipedia.org
26
Stoichiometry Limiting Reactant

• HCl Mg -------gt MgCl2
  H2
• What type of reactions is this?
• Balance equation if needed.
• If 6.8 moles of Mg react with 7.5 moles of HCl
  which is considered the limiting reactant? excess
  reactant?

Reactants Have (moles) Need (moles)


27
Stoichiometry Limiting Reactant

• 2HCl Mg -------gt MgCl2
  H2
• If 6.8 moles of Mg react with 7.5 moles of HCl
  how many moles of MgCl2 can be produced?

Reactants Have (moles) Need (moles)
HCl (limited) 7.5 mol 13.6
Mg (excess) 6.8 mol 3.75
28
Pre-AP Chemistry 4/26

• Objectives
• Identify and apply limiting reactants in
  stoichiometric calculations.
• Distinguish between theoretical and actual yield.
• Calculate yield.
• Homework
• Limiting and Yield worksheets.

29
Theoretical vs. Actual Yield of Products

• Theoretical yield maximum amount that can be
  produced according to the limiting reactant.
  (calculated yield)
• Actual yield actual amount produced in the
  lab.

30
Stoichiometry Limiting Reactant

• Limiting Reactant Al
• Theoretical Yield of AlCl3 3.0 moles
• Limiting Reactant C2H4
• Theoretical yield of H2O 5.4 moles
• Limiting Reactant N2
• Theoretical yield of NH3 34 g

31
Limiting Reactant
32
Stoichiometry Percent Yield

• 4. Theoretical Yield of AlCl3 3.0 moles
• Actual yield from lab of AlCl3 2.8 mole
• Yield of AlCl3
• 5. Theoretical yield of H2O 5.4 moles
• Actual yield from lab of H2O 4.9 moles
• Yield of H2O
• Theoretical yield of NH3 34 g
• Actual yield from lab of NH3 31.5 g
• yield of NH3

33
Stoichiometry Percent Yield

• Yield of Product
• Accuracy of product formation in the lab.
• Yield of product actual yield x 100
• theoretical
  yield
• Actual yield actual amount formed in lab
• Theoretical yield maximum amount that can be
  produced according to the limiting reactant.
  (calculated yield)

34
Pre-AP Chemistry (4/29)

• Objectives
• Identify and apply limiting reactants in a
  chemical equation.
• Calculate percent yield of products in a chemical
  equation.
• Identify what molarity is.
• Homework
• Complete Limiting and Yield worksheet.
• Read over lab and complete hypothesis section.
• Quiz Wednesday over stoichiometry, limiting
  reactants, and percent yield of products.

35
Bell Ringer Limiting Reactants and Yield

• C2H2 O2 ---? CO2
  H2O
• 1. Balance the equation if needed.
• If 2.40 moles of C2H2 reacts with 7.40 moles of
  O2 how many grams of water can be produced?
• What is the limiting reactant?
• Use limiting reactant to calculate theoretical
  yield of H2O in grams.
• If the actual yield of H2O in the lab was 40.1
  grams, calculate what the yield of H2O would
  be.

36
Stoichiometry

• Objectives
• Identify what stoichiometry is in chemistry.
• Apply stoichiometry calculations in chemical
  reactions.
• Identify and apply limiting reagents in chemical
  reactions.
• Calculate yield of products in a chemical
  reaction.