How much energy is released when 0.40 mol c6h6(g) completely reacts with oxygen? 2c6h6(g) + 15o2(g) --> 12co2(g) + 6h2o(g)

answers are

-2535
-1268
1258

Which best describes the present-day universe? opaque, expanding very slowly, stars produce heavy elements transparent, expanding at an accelerated rate, stars produce heavy elements opaque, expanding at an accelerated rate, stars produce only hydrogen and helium transparent, expanding very slowly, stars produce only hydrogen and helium