1. Yes, we want to transfer as much heat from the co2 enriched air as possible, using cooled air would be better because it would mean that co2 enriched air would be slightly less hot, slowing the rate of rising and increase the time for the co2 to transfer the heat to the water (i'm not sure about this)
2. We want to keep it as simple as possible to try and lower margin of error, we were originally going to do this, but we scratched it due to it's complexity
3. We want to keep the tubes as narrow as possible, but still wide enough for the co2 to leave, so we'll probably experiment with different sizes
4. it is connected (the clear portion is where the flame is and blue is the water), along with the heat transferred from the flame directly, we are trying to absorb as much heat and absorb some heat from the co2
5. Higher temperature means more vaporization meaning more heat loss, lower the calculated heat transferred (we're going to try and remove this issue as much as possible by using an air sealed container, or as close to this as possible)