0.04350179862
Explanation:
Make sure to check for sig figs though. Basically, you have 2.54 mL and you multiply that by the 0.789 g/mL and mL cancels out and you are left with 2.00406g. There are 46.06844 grams per mol of ethanol, so to cancel out grams we multiply by 1/46.06844. And then we are left with 0.04350179862 mol
It doesn't because pepper does not dissolve
That would be 222.0 mm to 4 sig figs
I believe you can simply add more cells in series to get a higher voltage. Not 100% sure on that.