Mole and Avogadro Number
Question:

Take a look into the attached video and answer the following question below! 

Propane (C3H8) burns in this reaction:

C3H8+5O2→4H2O+3CO2

If 12 g of propane is burned, how many grams and molecules of CO2 is produced?

2 People tried to answer this question

35.64 gram CO2, 4.877e23 molecules

2.64 gram CO2, 1.2132e23 molecules

26.4 gram CO2, 3.6132e23 molecules

33.64 gram CO2, 3.877e23 molecules

Excellent :)

Carbon (C) has 12.00 grams per mole.

Hydrogen (H) has 1.00 grams per mole.

Oxygen (O) has 16.00 grams per mole.

One molecule of Propane contains 3 carbon atoms and 8 hydrogen atoms.

Step 1: Mw (C3H8)= (3x12.00+8x1.00) gr/mole= 44 gr/mole

n=m/mw : Step 2:  12 gr C3H8 is equal to 0.27 mole C3H8.

Step 3:  Since there is a ratio of 3:1 CO2 to C3H8, for every 0.2 mole C3H8 there are 0.81 mole CO2 .

Step 3: Convert 0.81 mole CO2 to gram CO2.

n=m/mw :

Mw (CO2)=(12.00+2x16.00)=44 gr/mole.

0.81 mole CO2 is equal to 35.64 gram CO2.

Molecules of CO2: (0.81 mole)x(6.022e23 molecules/mole)=4.877e23 molecules

Try again ! 

Try again !

Try again !



Comments:
1.  Auinat Mahmud (28.06.2017 pm 12.30.25)
Peer Assessment

Hello Helana,

I really enjoyed reading your question. The explanation was clear and almost scientifically accurate but  you add a long  presentation instead of a short explanation and short animation  that made it more interesting and could wake up pupil curiosity.

About the multi choice question:

It's a calculation question that need understanding the relations between variables and parameters.  its a good question wrote in a correct way.

The answers: I think that the answers should built the way that if students use wrong parameters or variables will got one of the answers that you add. so i think that the answers built in a way the student can try until he got the correct answer.

Why do you think that the student will chose the wrong answer? you should add a note  after the wrong answer that explain why you think that the student got and chose this answer and try again using your note.

Correct answer: you add the correct method the student should answer the question and it's good to see that we answer it in a correct method.

There is no link to the BLOSSOMS lessons.

There is add point to the digital map

 

Best,

Mahmud



History of edits
Edited BY: Helana Sarboukh Edit Date: 2017-05-29 01:39:19
Edited BY: Helana Sarboukh Edit Date: 2017-05-29 01:39:18
Edited BY: Helana Sarboukh Edit Date: 2017-05-29 01:37:01
Edited BY: Helana Sarboukh Edit Date: 2017-05-29 01:34:48
Edited BY: Helana Sarboukh Edit Date: 2017-05-29 01:32:25
Edited BY: Helana Sarboukh Edit Date: 2017-05-29 01:31:14