5 pounds of diced onions would take 5 pounds of whole onions chopped up.
1 cup = 8 ounces regardless of what you are measuring.
Onions come in many sizes - this is one where you actually have to use your own judgement,
meow
128 ounces in a gallon.
One gallon = 128 ounces.
128 US ounces = 1 US gallon
1 US gallon = 128 fluid ounces
That is 1,536 ounces.
1 gallon = 128 fluid ounces 1/2 gallon = 64 fluid ounces
32
A US gallon is 128 ounces