Answer: The molar concentration of oxygen gas in water is
.
Explanation:
Partial pressure of the
gas = 685 torr = 0.8905 bar
1 torr = 0.0013 bar
According Henry's law:

Value of Henry's constant of oxygen gas at 20 °C in water = 34860 bar


Let the number of moles of
gas in 1 liter water be n.
1 Liter water = 1000 g of water
Moles of water in 1 L 




Molar concentration of oxygen gas in 1 L of water:

The molar concentration of oxygen gas in water is
.
Answer:
The answer to your question is 0.005
Explanation:
Data
Volume of NaOH = 25 ml
[NaOH] = 0.2 M
moles of NaOH = ?
To solve this problem is not necessary to have the chemical reaction. Just use the formula of Molarity and solve it for moles.
Formula
Molarity = moles / volume
-Solve for moles
moles = Molarity x volume
-Convert volume to liters
1000 ml ---------------- 1 l
25 ml ---------------- x
x = (25 x 1) / 1000
x = 0.025 l
-Substitution
moles = 0.2 x 0.025
-Result
moles = 0.005
Hot air balloons have hot air inside them, which is less dense as the air around it. Thus it rises. A cold air balloon would sink because the air would be more dense than the air around it. Also, the balloon’s volume would vary in size depending on the weight of the balloon.