CO(g) + 3 H2(g) → CH4(k) + H2O(g) + heat The sign of AH is
The sign of AS is
The sign of AG is negative a low or high temperature?

Explanation:

AH is negative because the reaction gives out heat (exothermic).

AS is negative because the total entropy of the reactants is greater than that of the products (there are 4 moles of gas on reactant side compared to only 1 mole on the product side). Thus, the reactants are said to be "messier" than the products.

AG is negative at lower temperatures because at low temperatures, -TAS is more negative, resulting in the negative sign of AG.

Hope this helps.