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Stoichiometry Problems for Distance Learning Students, Summaries of Stoichiometry

Pennsylvania State University - ShenangoStoichiometry

A packet of stoichiometry problems for students who do not have access to technology for distance learning. It includes calculations for determining the amount of a substance needed based on given amounts of another substance, as well as explanations for each step of the calculation. The packet covers the reactions of lead iodide and ammonia, and includes questions related to molar mass, mole ratios, and Avogadro's number.

Typology: Summaries

2021/2022

Uploaded on 09/12/2022

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!
1!
If you are a student that HAS access to technology, this is not the packet for you. This packet is
for students who pick up and drop off their work at the front office every week. If you have
access to technology, please go back to your teacher’s website and complete the correct
assignment.
!
Name:!_____________________________________________!Period:!____________!Teacher:!____________________________!
Distance)Learning)Week)8)Paper)Packet)
5/2555/31)
8.1$Stoichiometry:,Calculating,Chemical,Amounts!
(notes,(3(examples,(and(3(practice(problems)!
!
If#you#have#internet#access,#there#is#a#video#on#my#website#explaining#these#notes!##
When!potassium!iodide!(KI)!is!mixed!with!lead!nitrate!
(Pb(NO3)2),!a!yellow!solid!is!formed.!This!yellow!solid!is!lead!
iodide,!PbI2.!Lead!iodide!used!to!be!used!as!a!pigment!in!
yellow!paint,!but!is!now!used!to!detect!gamma!and!xFrays.!!
2#KI###+###Pb(NO3)2###à###PbI2###+###2#KNO3#
Molar&Mass&KI:&&166.0&grams&=&1&mol&
Molar&Mass&Pb(NO3)2:&&331.22&grams&=&1&mol&
Molar&Mass&PbI2:&&&461.0&grams&=&1&mole&
Molar&Mass&KNO3:&&&101.11&grams&=&1&mole&
1. I!need!15.5!grams!of!PbI2.!How!many!moles!of!KI!do!I!
need!to!use!to!make!it?!!
Given!(with!units!):!15.5!grams!of!PbI2!
Desired!units:!moles!of!KI!
Calculation:!!
15.5!grams!PbI2!
1!mol!PbI2!
2!mol!KI!
=!0.0672!mol!KI!
(remember:&nothing&goes&
here!)&
461.0!g!PbI2!
1!mol!PbI2!
(remember:&nothing&goes&
here!)!
!
Explanation!for!each!step:!
Use!molar!mass!to!convert!
grams!of!PbI2!to!moles!of!
PbI2!
Use!mole!ratio!to!convert!
moles!of!PbI2!to!moles!of!KI!
Calculate!by!multiplying!by!
the!top/dividing!by!the!
bottom!(15.5!÷!461.0!x!2)!
pf3
pf4
pf5

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Download Stoichiometry Problems for Distance Learning Students and more Summaries Stoichiometry in PDF only on Docsity!

If you are a student that HAS access to technology, this is not the packet for you. This packet is for students who pick up and drop off their work at the front office every week. If you have access to technology, please go back to your teacher’s website and complete the correct assignment. Name: _____________________________________________ Period: ____________ Teacher: ____________________________

Distance Learning Week 8 Paper Packet

8.1 Stoichiometry: Calculating Chemical Amounts

(notes, 3 examples, and 3 practice problems)

If you have internet access, there is a video on my website explaining these notes! When potassium iodide (KI) is mixed with lead nitrate (Pb(NO 3 ) 2 ), a yellow solid is formed. This yellow solid is lead iodide, PbI 2. Lead iodide used to be used as a pigment in yellow paint, but is now used to detect gamma and x-­‐rays. 2 KI + Pb(NO 3 ) 2 à PbI 2 + 2 KNO 3 Molar Mass KI: 166.0 grams = 1 mol Molar Mass Pb(NO 3 ) 2 : 331.22 grams = 1 mol Molar Mass PbI 2 : 461.0 grams = 1 mole Molar Mass KNO 3 : 101.11 grams = 1 mole

  1. I need 15.5 grams of PbI 2. How many moles of KI do I need to use to make it? Given (with units!): 15.5 grams of PbI 2 Desired units: moles of KI Calculation: 15.5 grams PbI 2 1 mol PbI 2 2 mol KI = 0.0672 mol KI (remember: nothing goes here!) 461.0 g PbI 2 1 mol PbI 2 (remember: nothing goes here!) Explanation for each step: Use molar mass to convert grams of PbI 2 to moles of PbI 2 Use mole ratio to convert moles of PbI 2 to moles of KI Calculate by multiplying by the top/dividing by the bottom (15.5 ÷ 461.0 x 2)
  1. If I want to make 15.5 grams of PbI 2 , how many grams of Pb(NO 3 ) 2 will I need to use? Given (with units!): 15.5 grams of PbI 2 Desired units: grams Pb(NO 3 ) 2 Calculation: 15.5 grams PbI 2 1 mol PbI 2 1 mol Pb(NO 3 ) 2 331.22 g Pb(NO 3 ) 2 = 11.1 g Pb(NO 3 ) 2 (remember: nothing goes here!) 461.0 g PbI 2 1 mol PbI 2 1 mol Pb(NO 3 ) 2 (remember: nothing goes here!) Explanation for each step: Use molar mass to convert grams of PbI 2 to moles of PbI 2 Use mole ratio to convert moles of PbI 2 to moles of Pb(NO 3 ) 2 Use molar mass to convert moles of Pb(NO 3 ) 2 to grams of Pb(NO 3 ) 2 Calculate by multiplying by the top/dividing by the bottom (15.5 ÷ 461.0 x 331.22)
  2. If I use 4.8 x 10^23 particles of KI, how many grams of PbI 2 can be made? Given (with units!): 4.8 x 10^23 particles of KI Desired units: grams of PbI 2 Calculation: 4.8 x 10^23 particles KI 1 mol KI 1 mol PbI 2 461.0 g PbI 2 = 180 g PbI 2 (remember: nothing goes here!) 6.02 x 10^23 particles KI 2 mol KI 1 mol PbI 2 (remember: nothing goes here!) Explanation for each step: Use Avogadro’s number to convert particles of KI to moles of KI Use mole ratio to convert moles of KI to moles of PbI 2 Use molar mass to convert moles of PbI 2 to grams of PbI 2 Calculate by multiplying by the top/dividing by the bottom (remember to put Avogadro’s number in parentheses!) Try these problems on your own, then check your answers. The answers are at the bottom of the page. If you have internet access, there is also a video showing how to do the problems on my website. The reaction below is called the Haber process. It was developed by Fritz Haber in the early 1900s. Ammonia, NH 3 , is the main component in fertilizer; this is the main use of the Haber process today. However, ammonia is also used in many cleaning products such as Windex. Balance: ______ H 2 + ______ N 2 à ______ NH 3 MM H 2 : 2.016 grams = 1 mol MM N 2 : 28.02 grams = 1 mol MM NH 3 : 17.034 grams = 1 mol
  3. If I start with 6.8 x 10^23 particles of H 2 , how many particles of N 2 will I need to use? Given (with units!): _________________________ Desired units: __________________________ Calculation:

Assignment 8.2 Stoichiometry Practice

Before you begin, make sure you have completed assignment 8.1. Please show your work. You must show your work in order to receive full credit. Use the mole Island Graphic Organizer (Page ) to guide you. A partial answer key is also included for you. YOU MUST SHOW YOUR WORK TO RECEIVE FULL CREDIT!!!

Use the following balanced chemical equation to answer questions 1-4:

C 3 H 8 + 5O 2 → 4H 2 O + 3CO 2

1. If I want to make 3.00 moles of H 2 O, how many grams of C 3 H 8 do I need?

Given/ start with units (X): 3 moles of H 2 O

Desired/ end with units (Y) : grams of C 3 H 8

Step 1. Write what you start with in the top left, what you end with goes in the top right.

Step 2. Make plan from start → end using mole island island

moles of (X) → moles of (Y) → grams of (Y)

Step 3. Using dimensional analysis and mole island, convert from X → Y

Each mole island arrow will be one column of dimensional analysis

You will have to calculate molar mass in some problems

The molar ratio of C 3 H 8 : H 2 O is 1 mol of C 3 H 8 : 4 mol of H 2 O

3 moles of H 2 O

(start)

1 mol of C 3 H 8 44.097 grams of

C 3 H 8

grams of C 3 H 8

(end)

(This area

remaines blank)

4 mol of H 2 O 1 mol of C 3 H 8 (This area

remaines blank)

2. If I use 50.0 grams of O 2 , how many grams of C 3 H 8 will I use?

Given/ start with units (X): 50.0 grams of O 2

Desired/ end with units (Y): grams of C 3 H 8

Mole island pathway: grams of (X) → moles of (X) → moles of (Y) → grams of (Y)

50.0 grams of

O 2

grams of C 3 H 8

(This area

remaines

blank)

(This area

remaines

blank)

3. If I want to make 12 moles of CO 2 , how many particles of C 3 H 8 will I use?

a. Given/ start with units (X): ___________

b. Desired/ end with units (Y): _____________

c. Mole island map: Moles of (X) → moles of (Y) → particles of (Y)

(start) (end)

4. If I use 8.65 x 10^23 particles of C 3 H8, how many grams of CO 2 will I use?

Use the following balanced chemical equation to answer questions 5- 8 :

2 Al + Fe 2 O 3 → Al 2 O 3 + 2 Fe

5. Mr. Lim is going to perform a thermite reaction. How many moles of Al should he use if he wants to

make 123 grams Fe?

6. If Mrs. Macedo produces 1.01 x 10^23 particles of Al 2 O 3 , how many particles of Fe 2 O 3 were used?

7. How many grams of Al will Mrs. Meemari needs to make 4.80 moles of Al 2 O 3?

8. If Mrs. Richardson produce 92 grams of Al 2 O 3 , how many grams of Fe 2 O 3 did she use?

9. (Super) Challenge (Optional): 2 Al + Fe 2 O 3 → Al 2 O 3 + 2 Fe

I have 2.000 pounds of Al and 5.000 pounds of Fe 2 O 3 , how many moles of Fe can I make? How many grams?

(hint: 453.6 grams = 1 lb, there is a limiting reactant as well)