Answer : The molecular weight of a gas is, 128.9 g/mole
Explanation : Given,
Density of a gas = 5.75 g/L
First we have to calculate the moles of gas.
At STP,
As, 22.4 liter volume of gas present in 1 mole of gas
So, 1 liter volume of gas present in
mole of gas
Now we have to calculate the molecular weight of a gas.
Formula used :

Now put all the given values in this formula, we get the molecular weight of a gas.


Therefore, the molecular weight of a gas is, 128.9 g/mole
The properties of a compound are different than the properties of the element that forms it
Answer:
The entropy of the final solution decreases, as the reaction disorder is less.
Explanation:
The higher the temperature, the greater the heat of the reaction and the greater the disorder it has, so the entropy will increase ... But this is not the case, since the solution cools, decreasing the entropy proportionally.