Which one of the following is an extensive property?

For the isothermal expansion of an ideal gas:

For $1 \, \text{mole}$ of an ideal gas,isothermal expansion occurs from a volume of $2 \, L$ to $6 \, L$ at a temperature of $300 \, K$. The value of $\Delta U$ for this process is .............

What is meant by standard state?

One mole of an ideal gas at $300 \ K$ and $20 \ atm$ expands to $2 \ atm$ under isothermal and reversible conditions. The work done by the gas is $-x \ kJ \ mol^{-1}$. The value of $x$ is $(R = 8.3 \ J \ K^{-1} \ mol^{-1})$

Consider the following reaction:
$CO_{(g)} + 1/2 O_{2_{(g)}} \to CO_{2_{(g)}}$
How are $\Delta E$ and $\Delta H$ related for the reaction?