2 bottles
If the scoops are the same size, 50 with 2 scoops and 100 with 4 scoops have the same concentration. 2/50 = 0.04 4/100 = 0.04 but 150 with 5 scoops has less concentration 5/150 = 0.0333
To effectively disinfect water, you should add 8 drops of bleach per gallon of water.
No, salt is more dense than sugar, so three scoops of salt will weigh more than three scoops of sugar in the same volume of water.
To effectively sanitize, you should add 1/4 cup of bleach per gallon of water.
A gallon of water per person per day
1 gallon. Sugar is soluble in water and should not significantly change the volume
Should the gas in question be water vapour then there is one gallon of water. (In gaseous form) Should the gas be anything else then it is possible that there may be some contamination. How much of that is water depends on the amount of contamination.
three seconds
A gallon of water per person per day
Change 10% of your water (so 1 gallon of water if you have a 10 gallon tank) per week. Change at least 25% of your water monthly.
75 gallon
A gallon of water per person per day