Download Stoichiometry Notes

Stoichiometry.notebook
August 12, 2015
How to find moles!!!
moles
E­AMA
Mass =
Molar Mass
PV =
RT
M x V =
Aug 19­8:54 AM
Aug 19­8:54 AM
Find Moles (Don't use a calculator, approximate)
A) 80 grams of NaOH (FW = 40)
B) 500 mL of a 4.0 M solution of CuSO4
Find Grams
A) 0.5 moles of H2O
C) 2.0 L of CO2 at 2.0 atm and 100K
B) 250 mL of a 2.0 M solution of NaCl (MW=58)
C) 2.00 moles of NH3
Aug 19­9:11 AM
Draw a particle representation of this
experiment
(may have to draw more than one scenario)
Aug 19­9:20 AM
Start with these problems...
1) 24 grams of carbon ­ find moles
2) 0.5 moles of sulfur ­ find grams
3) 22 grams of CO 2 ­ find grams of just C
4) 500mL of 0.6 M of a solution ­ find moles
Aug 20­7:51 AM
Aug 23­8:14 AM
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Stoichiometry.notebook
Solve these problems
August 12, 2015
C6H12 O6 (aq) ⇒2 C2H5OH (aq) + 2 CO2 (g)
A) Find the number of moles of carbon in one propane, C3H8.
B) Find the number of moles of carbon in 3.0 moles of propane.
C) Find the number of grams of carbon in 2.0 moles of propane.
D) The US Debt...
A) How many moles of CO2 are produced when 0.400 moles of C6H12 O6 reacts?
B) How many grams of C6H12 O6 (MW = 180) are needed to form 45 g of C2H5OH (MW = 45)?
C) How many grams of CO2 (FW = 44) form when 92 g of C2H5OH (FW = 45) are produced?
Aug 19­9:30 AM
Aug 19­9:53 AM
When class starts (without any notes)
Write the balanced chemical reaction for:
1. Equimolar solutions of sodium chloride and silver nitrate are mixed.
2. A solution of lead nitrate is added to a solution of sodium iodide.
Aug 22­8:19 AM
Al(OH)3 (s) + 3 HCl (aq) ⇒ AlCl3 (aq) + 3 H2O(l)
Aug 21­3:32 PM
2 H2 (g) + O2 (g) ⇒ 2 H2O (g)
Initial
Draw what happens
when the reaction comes
to completion
A) Starting with 156 grams of Al(OH)3 (48 g mol­1 ), how many moles of water are formed?
B) If 500 mL of 2.00 M HCl is used, how many moles of water is produced? How many total moles of products are produced?
Aug 19­10:00 AM
Aug 24­7:58 AM
2
Stoichiometry.notebook
August 12, 2015
Goal: Determine the number of moles of
N2 (g) + 3 H2 (g) ⇒ 2 NH3 (g)
water in CuSO4 x H2O
Data:
Calculations:
Aug 22­8:21 AM
3 mol
3 mol
Aug 24­7:58 AM
2 NaOH (s) + CO2 (g) ⇒ Na2CO3 (s) + H2O (l)
Dilutions
M1V1 = M2V2
when the moles A) Find the volume of 6.0 M HCl solution
are needed to make 500 mL
of a 3.0 M solution.
equal
A) Which reagent is the limiting reactant when 1.00 moles of NaOH is allowed to react with 1.00 moles of CO2?
B) If you take 100 mL of 2.0 M NaOH and
add 400 mL of water to it, what is the new
concentration of your solution?
C) How many moles of excess reactant remains after completion?
Aug 19­9:46 AM
B) How many moles of Na2CO3 can be produced?
Aug 19­10:07 AM
A) How many grams of carbon are found in 33 grams of CO2?
B) How many grams of hydrogen are found in 36 grams of H2O?
C) If a sample that contains only C, H, & O is originally 30 grams and is found to have 12 grams of carbon and 2 grams of hydrogen. How many grams are oxygen and what is the empirical formula?
Aug 26­7:45 AM
Aug 26­10:52 AM
3
Stoichiometry.notebook
CH4 (g) + 2 O2 (g) ⇒ CO2 (g) + 2 H2O (g)
A) If 32.0 g of CH4 (FW = 16) reacts with 32.0 g of O2 (FW = 32), what is the limiting reactant?
B) How many moles of CO2 is formed?
C) How many grams of water is formed?
D) How many grams of excess remain?
Aug 19­10:10 AM
Multiple Choice
2 Na (s) + 2 H2 O (l) ⇒ 2 NaOH (aq) + H2 (g)
If a sample of sodium reacts completly to form 0.5 grams of hydrogen gas, what is the mass of the sodium that has reacted?
a) 5.0 g
b) 11.5 g
c) 23 g
d) 46 g
e) 69 g
Aug 19­10:15 AM
August 12, 2015
Multiple Choice
Fe2 O3 + CO ⇒ Fe + CO2
(unbalanced)
How many moles of CO are required to form one mole of Fe?
(a) 0.5
(b) 1
(c) 1.5
(d) 2
(e) 3
Aug 19­10:14 AM
Multiple Choice
CaCO3 (s) + 2H+(aq)⇒Ca2+ (aq) + H2 O(l) + CO2 (g)
If the above reaction took place at standard temperature and pressure and 150 grams of CaCO3 were consumed, what is the volume of CO2 produced?
a) 11 L
b) 22 L
c) 34 L
d) 45 L
e) 56 L
Aug 19­10:33 AM
Multiple Choice
2 HBr (aq) + Zn (s) ⇒ ZnBr2 (aq) + H2 (g)
If 130 grams of zinc was added to a solution of 162 grams of HBr, how many grams of hydrogen gas will be produced?
a) 1 g
b) 2 g
c) 4 g
d) 8 g
e) 16 g
Aug 19­10:41 AM
find M of Zn +2
M = mol
L
Aug 22­4:23 PM
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Stoichiometry.notebook
August 12, 2015
Rank in Order of
Mass %
Lowest
Mass Percent
of Nitrogen
% Composition = Highest
Mass Percent
of Nitrogen
Choice B
Choice A
Molar Mass x 100%
Total Molar Mass
Mass x 100%
Total Mass
NO
NO2
Aug 19­10:36 AM
N2O
N2O4
Aug 23­7:50 AM
Multiple Choice
If there are 11 grams of CO2, how many grams are just carbon?
What is the mass of oxygen in 148 grams of Ca(OH)2?
a) 16 g
b) 24 g
c) 32 g
d) 48 g
e) 64 g
Aug 23­8:03 AM
Multiple Choice
If 250 grams of CuSO4 xH2O is heated until all the water is removed. If 160 grams remains, how many moles of water were there initially? a) 1
b) 2
c) 5
d) 8
e) 10
Aug 19­10:40 AM
Aug 19­10:40 AM
Multiple Choice
If 61 grams of BaCl2 xH2O is heated until all the water is removed. If 52 grams remains, how many moles of water were there initially? a) 1
b) 2
c) 3
d) 4
e) 5
Aug 19­10:40 AM
5
Stoichiometry.notebook
August 12, 2015
Chemical Formula
Empirical Formula
(ii) the mass of H2O lost
Aug 22­4:27 PM
What is a Chemical Formula?
A Ratio of Moles
C4H12 O6
H2O
C3H8
H2 O2
P2O5
N2H4
Aug 22­4:19 PM
Determine the Empirical Formula
71.5 grams Cl
24.4 grams C
6.2 grams H
Aug 23­8:08 AM
How do you determine the molecular formula?
What do you need?
Multiplier = True Molar Mass
Empirical Formula Molar Mass
Aug 23­8:22 AM
Aug 23­8:12 AM
Multiple Choice
Analysis of a sample of an oxide of chromium is reported as 26 g of chromium and 12 g of oxygen. From these data determine the empirical formula of this compound
(A) CrO
(B) Cr2O3
(C) CrO3
(D) CrO2
(E) Cr4O6
Aug 23­8:26 AM
6
Stoichiometry.notebook
August 12, 2015
Multiple Choice
Multiple Choice
A hydrocarbon contains 75% carbon by mass. What is the empirical formula for the compound?
When chlorine gas is combined with fluorine gas, a compound is formed that is 38% chlorine and 62% fluorine. What is the empirical formula of the compound?
(A) ClF
(B) ClF2
(C) ClF3
(D) ClF5
(E) ClF7
(A) CH2
(B) CH3
(C) CH4
(D) C2H5
(E) Cr3H8
Aug 23­8:36 AM
Aug 23­8:36 AM
Decomposition of a Hydrate Test
• 3 Pieces of Equipment
• 3 Measurements
• Clearly show 4 Calculations
(Do not have to show numbers, but show what you would add/subtract/multiply/divide)
Aug 29­8:39 AM
Aug 29­8:02 AM
An organic compound of 5.000g containing
carbon, hydrogen, and oxygen is combusted
producing 7.333g of carbon dioxide and
3.000g of water.
(i) Calculate the individual masses of C, H, and O.
(ii) Determine the empirical formula.
Aug 29­7:42 AM
Aug 22­4:20 PM
7
Stoichiometry.notebook
August 12, 2015
A 4.000g sample of an unknown organic
compound containing C, H, and O is
combusted in excess oxygen gas. It
produces 7.652g of CO2 and 4.696g of H2 O
at 25oC. The sample is found to have a
formula weight of approximately 90 g mol-1.
6.602 g
(c) Determine the empirical formula of acetylsalicylic acid.
Do not round!
Aug 22­4:22 PM
Multiple Choice
How many grams of sodium hydroxide, NaOH, is necessary to make a 250mL of 0.5 M NaOH?
(A) 2.5 g
(B) 5.0 g
(C) 10.0 g
(D) 20.0 g
(E) 40.0 g
Aug 30­8:57 AM
Multiple Choice
What is the formula for a compound formed by combining 50. g of element X (atomic weight = 100.) and 32 grams of oxygen?
(A) XO2
(B) XO4
(C) X4O
(D) X2O
(E) XO
Aug 30­8:18 AM
(i) Calculate the individual mass of C, H, and O.
(ii) Determine the empirical formula.
(iii) Determine the molecular formula.
Aug 31­8:01 AM
Multiple Choice
Unknown element X combines with oxygen to form the compound XO2. If 44.0 g of element X combines with 8.00 g of oxygen, what is the atomic mass of element X?
(A) 16 amu
(B) 44 amu
(C) 88 amu
(D) 176 amu
(E) 352 amu
Aug 24­8:04 AM
Multiple Choice
BaCl2 (aq)+K3 AsO4 (aq)⇒Ba3 (AsO4 )2 (s)+KCl(aq)
(unbalanced)
When 0.600 mol of BaCl2 (aq) is mixed with 0.250 mol of K3AsO4 (aq), what is the maximum number of moles of solid Ba 3
(AsO4)2 that could be formed?
(A) 0.125 mol
(B) 0.200 mol
(C) 0.250 mol
(D) 0.375 mol
(E) 0.500 mol
Aug 30­8:36 AM
8
Stoichiometry.notebook
Multiple Choice
A hydrocarbon was found to be 20%
hydrogen by weight. If 1 mole of the
hydrocarbon has a mass of 30 grams,
what is the molecular formula?
(A) CH
(B) CH2
(C) CH3
(D) C2H4
(E) C2H6
Aug 30­8:40 AM
2 Cu (s) + 1/2 O2 (g) ⇒ Cu2 O (s)
Copper reacts with oxygen gas to produce copper (I) oxide, as represented by the equation above. A 100.0 g sample of Cu (s) is mixed with 40.00 g of O2.
(a) Calculate the number of moles of each reactant before the reaction begins.
(b) Identify the limiting reactant when the mixture is heated to produce Cu2O. Support your answer with calculations.
(c) Calculate the maximum number of moles of Cu2O produced when the reaction proceeds to completion.
Aug 30­8:30 AM
Multiple Choice
A compound is found to be composed of carbon, hydrogen, and oxygen. It is found to have 38.71% carbon and 9.68% hydrogen. Which of the following is a possible empirical formula for this compound?
(A) CHO
(B) CH2O
(C) CH3
(D) C2H5O
(E) CH3O
Sep 6­9:11 AM
August 12, 2015
Multiple Choice
CaCO3 (s) ⇒ CaO (s) + CO2 (g)
A sample of pure CaCO3 (MW=100) was heated and decomposed according to the reaction given above. If 28 grams of CaO were produced by the reaction, what was the initial mass of CaCO­3?
(A) 14 g
(B) 25 g
(C) 42 g
(D) 50 g
(E) 84 g
Aug 31­8:14 AM
Multiple Choice
Estimate the mass of CaCl2 (FW=111) required to prepare 75mL of a 2M solution of this salt. (A) 150 g
(B) 16.65 g
(C) 8.325 g
(D) 1.65 x 104 g
(E) 222g
Aug 31­12:22 PM
Multiple Choice
Commercial nitric acid is approximately 16M. What volume of this must be used to prepare 80mL of 4M nitric acid?
(A) 10 mL
(B) 20 mL
(C) 30 mL
(D) 40 mL
(E) 50 mL
Sep 6­9:13 AM
9
Stoichiometry.notebook
Multiple Choice
Hydrogen reacts with oxygen to produce water.
If 16 grams of hydrogen gas is mixed with 16 grams of oxygen gas, how much water can be formed?
(A) 5.0 g
(B) 8.0 g
(C) 18 g
(D) 32 g
(E) 144 g
Sep 6­9:20 AM
August 12, 2015
Multiple Choice
CH4 + 2O2 ⇒ CO2 + 2H2O
According to the reaction above, how much methane must be reacted to form 72 g of water?
(A) 16 g
(B) 32 g
(C) 36 g
(D) 84 g
(E) 72 g
Sep 6­9:21 AM
Combustion of 0.105 g of an unknown compound containing C, H, and O yielded 0.257 g CO2 and 0.0350 g H2 O. • Find the empirical formula for this compound.
• If the molar mass is 108 g/mol, what is the molecular formula?
Aug 31­7:51 AM
Free Response
A 10.0 g sample of an Cu xOy is heated in a stream of pure hydrogen gas, forming 1.26 g of water.
(a) Determine the percentage of copper in the compound.
(b) Determine the empirical formula of the copper oxide.
Sep 6­9:23 AM
Aug 31­7:30 AM
Free Response
An organic compound contains 46.7% of nitrogen, 6.67% of hydrogen, 26.7% of oxygen, and the remainder is carbon.
(a) Determine the empirical formula for this compound.
(b) If the molar mass is approximately 60 g/mol, what is the molecular formula?
Sep 6­9:25 AM
10
Stoichiometry.notebook
August 12, 2015
Princeton Review Guide
Pg. 70-72 #7, 8, 10, 13, 15, 16, 20, 21
Sep 6­1:43 PM
Aug 31­8:42 AM
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