AP Chem, balance Redox equation

AI Thread Summary
To balance redox equations, first assign oxidation numbers to all elements involved. Identify which element is oxidized and which is reduced, then write separate half-reactions for each process. Balance the number of atoms and charges by adding electrons where necessary, and include H+ or OH- ions to balance hydrogen and oxygen if needed. For the example provided, the reaction Fe2O3 + 2Al → 2Fe + Al2O3 illustrates this process, showing how to achieve balance in both atoms and charges. Understanding these steps is crucial for successfully balancing redox equations in AP Chemistry.
gigi9
Messages
40
Reaction score
0
Please help me w/ the 2 redox equations. Show me how to assign the oxidation # and how to do it please, especially the 1st problem. The problems are attached. Thank you very much for ur time.
 

Attachments

Last edited:
Physics news on Phys.org
Below attachment is my redox equation
 


Sure, I'd be happy to help with balancing redox equations. First, let's review the steps for balancing a redox equation:

1. Assign oxidation numbers to all elements in the equation.
2. Identify the element that is undergoing oxidation and the element that is undergoing reduction.
3. Write separate half-reactions for the oxidation and reduction processes.
4. Balance the number of atoms on each side of the equation.
5. Balance the charges by adding electrons to one side of the equation.
6. Make sure the total charge and number of atoms are balanced on both sides.
7. If necessary, add H+ or OH- ions to balance the hydrogen and oxygen atoms.
8. Combine the half-reactions and simplify if possible.
9. Check that the charges and atoms are balanced on both sides.

Now, let's apply these steps to the two equations you provided:

Problem 1:
Fe2O3 + Al → Fe + Al2O3

Step 1: Assign oxidation numbers to all elements.
Fe2O3: Fe has an oxidation number of +3 and O has an oxidation number of -2.
Al: Al has an oxidation number of 0.
Fe: Fe has an oxidation number of 0.
Al2O3: Al has an oxidation number of +3 and O has an oxidation number of -2.

Step 2: Identify the element undergoing oxidation and reduction.
In this case, Fe is being reduced from +3 to 0 and Al is being oxidized from 0 to +3.

Step 3: Write separate half-reactions.
Reduction: Fe2O3 → Fe
Oxidation: Al → Al2O3

Step 4: Balance the number of atoms.
Reduction: Fe2O3 → 2Fe
Oxidation: 2Al → Al2O3

Step 5: Balance the charges.
Reduction: Fe2O3 + 3e- → 2Fe
Oxidation: 2Al → 2Al3+ + 6e-

Step 6: Make sure the total charge and number of atoms are balanced.
Reduction: Fe2O3 + 3e- → 2Fe
Oxidation: 2Al → 2Al3+ + 6e-
Overall: Fe2O3 + 2Al → 2Fe + 2Al3+

Step
 
Kindly see the attached pdf. My attempt to solve it, is in it. I'm wondering if my solution is right. My idea is this: At any point of time, the ball may be assumed to be at an incline which is at an angle of θ(kindly see both the pics in the pdf file). The value of θ will continuously change and so will the value of friction. I'm not able to figure out, why my solution is wrong, if it is wrong .
TL;DR Summary: I came across this question from a Sri Lankan A-level textbook. Question - An ice cube with a length of 10 cm is immersed in water at 0 °C. An observer observes the ice cube from the water, and it seems to be 7.75 cm long. If the refractive index of water is 4/3, find the height of the ice cube immersed in the water. I could not understand how the apparent height of the ice cube in the water depends on the height of the ice cube immersed in the water. Does anyone have an...
Back
Top