Which of the following statement is false?
(1) Internal energy of an ideal gas depends only on the temperature.
(2) The relation between $\Delta U$ and $\Delta / /$ is $\Delta / l=\Delta U+$ $P \Delta K$
(3) Heat of a reaction at constant pressure is equal to $I f_{\mathrm{k}}-\|_{\mathrm{p}}$
(4) Heats of reaction at constunt pressure $(\triangle / f)$ and at constant volume $(\Delta U)$ are related as $\Delta / /-\Delta U=$ $\Delta n R T$