What's the volume of 140g of Ar(g) at STP?

Which statement about hf is true? it is zero for any compound in its standard state. it is positive when the bonds of the product store more energy than those of the reactants. it is negative when a compound forms from elements in their standard states. it is zero for any element that is in the liquid state.

At element makes up all organic compounds?

0.070g of hydride of carbon occupies 56cm^3 at s.t.p when vaporized and contained 14.29% by mass of hydrogen.what is the formula for the hydrocarbon