Step 1: Recall the expression for kinetic energy of an ideal gas.
For an ideal gas, the average kinetic energy of one mole is
\[
KE=\frac{3}{2}RT
\]
where
\[
R
\]
is the gas constant and
\[
T
\]
is the absolute temperature.
Thus, kinetic energy depends only on temperature and not on the nature or mass of the gas molecules.
Step 2: Analyze each statement.
Statement (1):
It says that kinetic energy depends on the mass of gas molecules.
This is incorrect because
\[
KE=\frac{3}{2}RT
\]
contains only temperature.
Hence, statement (1) is false.
Statement (2):
Since kinetic energy is directly proportional to temperature,
\[
KE\propto T
\]
Therefore, kinetic energy increases with increase in temperature. This statement is true.
Statement (3):
\[
1\,g
\]
of
\[
H_2
\]
corresponds to
\[
\frac{1}{2}\text{ mole}
\]
and
\[
8\,g
\]
of
\[
O_2
\]
also corresponds to
\[
\frac{8}{32}=\frac{1}{4}\text{ mole}
\]
Since total kinetic energy depends on number of moles,
\[
\frac{1}{2}\text{ mole of }H_2
\]
has greater kinetic energy than
\[
\frac{1}{4}\text{ mole of }O_2
\]
Thus, statement (3) is true.
Statement (4):
At a fixed temperature, kinetic energy depends only on temperature and not on pressure. Hence, this statement is also true.
Step 3: Final conclusion.
Therefore, the false statement is
\[
\boxed{\text{Kinetic energy of }1\text{ mol of gas depends on mass of the gas molecule}}
\]