Which has more mass? a
1 mole of Carbon
b
1 mole of Oxygen
c
1 mole of Chlorine
d
1 mole of Hydrogen

Explanation:

12.00 g C-12 = 1 mol C-12 atoms = 6.022 × 1023 atoms

 The number of particles in 1 mole is called Avogadro’s Number (6.0221421 x 1023).

6.022 ×1023 atoms

1 mol or     1 mol

6.022 ×1023 atoms

2h2o2--> 2h2o + o2

this reaction is of the spontaneous decomposition of hydrogen peroxide down into water and oxygen.

add 2 molecules of hydrogen peroxide and 2 molecules of water. since oxygen is naturally diatomic, the total number of atoms of each element is now the same on both sides of the equation so it is balanced.

this may not be entirely correct but let me know.

"standard molar enthalpy:

h2o ( liquid water ) : - 285.8 kj/mole

h2o ( water vapor ) : - 241.8 kj / mole.

δhrxn = - 241. 8 - ( - 285.8 )= -241.8 + 285.8 = 44.0

answer: 44.0 kj"