during a molar volume of oxygen experiment indicate how each of the following errors would affect (increase, decrease, or no change) your calculated value for the molar volume of O2 at STP.

Question

1.) Your sample was not completely decomposed.
2.) After you finish heating sample & the system cooled to room temperature, you closed the clamp on tube D without re-equalizing the pressures inside and outside of the flask, The water in beaker E was 4 inches deep & the water in flask C was 2 inches deep.

Answer 1

I don't know every step you followed; therefore, I'm hesitant to get into detail but here is what you should do.
Make list on a page of each step you followed. Beside each step, place the calculation formula used for that step. Then analyze each step, take the results and go to the next step until you get to the end.
Here is an example.
Suppose we standardize a NaOH solution with KHP (potassium hydrogen phthalate).
1. Weigh KHP primary standard.
2. moles KHP = grams KHP/molar mass.
3. Titrate KHP with NaOH.
4. Record mL NaOH.
5. Calculate M NaOH from mL NaOH x M NaOH = moles KHP

Now the problem might say, "We weigh the KHP but a small amount of KHP did not get transferred to the titration flask and we didn't notice it. What is the effect on M NaOH?"
Ans: grams KHP is too high which makes moles too high from step 2. Larger KHP moles in step 5 gives M NaOH too high.
I hope this helps.