C, im pretty sure if im wrong my bad
Answer : The correct option is, (B) 
Solution :
According to the Graham's law, the rate of effusion of gas is inversely proportional to the square root of the molar mass of gas.

or,
..........(1)
where,
= rate of effusion of unknown gas = 
= rate of effusion of oxygen gas = 
= molar mass of unknown gas = ?
= molar mass of oxygen gas = 32 g/mole
Now put all the given values in the above formula 1, we get:


The unknown gas could be carbon dioxide
that has approximately 44 g/mole of molar mass.
Thus, the unknown gas could be carbon dioxide 
Answer:
6.25 X10^{-9} = Ka

Explanation:
The ionic equation for the hydrolysis of the cation of the given salt will be:

The expression for Ka will be:
Ka = ![\frac{[H^{+}][MOH]}{[M^{+}]}](https://tex.z-dn.net/?f=%5Cfrac%7B%5BH%5E%7B%2B%7D%5D%5BMOH%5D%7D%7B%5BM%5E%7B%2B%7D%5D%7D)
As given that the concentration of the salt is 0.1 M and pH of solution = 4.7, we can determine the concentration of Hydrogen ions from the pH
pH = -log [H⁺]
[H⁺] = antilog(-pH) = antilog (-4.7) = 2 X 10⁻⁵ M = [MOH]
Let us calculate Ka from this,
Ka = 
The relation between Ka an Kb is
KaXKb =10⁻¹⁴

Find the average of these 2 temperatures, since they have the same volume.
(80 + 10) ÷ 2 = 90 ÷ 2 = 45°C
You can only use this method of averaging them out because they have the same volumes :)
Answer:
The temperature of the gas after it is filled is 596 K
Explanation:
According to Gay-Lussac law, the pressure of a gas mass is directly proportional to temperature to a constant volume. That means than if pressure rise, the temperature too. We can assume then the volume is constant because the tank is isolated. The tank will be full when pressure will be in equilibrium, that means when pressure will be 1 atm because it is environment pressure. Using the following equation:
P1 /T1 = P2 /T2 and replacing, T2 = P2 *T1 / P1 = 1 atm * 298K / 0.5 atm = 596 K.
I hope my answer helps you