"How long" measures distance, length and units of time. "How much" is the question we ask when we want to measure uncountable things like air, water, money, time, information, etc. We answer the question in units, which we can count, and then we switch from "much" to "many" (e.g., "Question: How much water is in the ocean? Answer: There are many liters of water in the ocean.").

are you learning english or french?? i look to your profile and i confuse want you want to learn about. how long is for asking time, while how much is for counting money how big or tall is asking for object/shape how far is asking for place how many is asking for quantity.