Water left in a freezer is called ice
1 CH4 (g) + 2 O2 (g) -----> CO2 (g) + 2H2O(l) ΔH= - 890 kJ
1 mol 2 mol
1) If ΔH has minus, it means "release". We need only "release" choices.<span>
2) From reaction
1 mol </span>CH4 (g) "releases" ΔH= - 890 kJ - We do not have this choice.
2 mol O2 (g) "release" ΔH= - 890 kJ, so
1 mol O2 (g) "release" ΔH= - 445 kJ
Correct answer is B.
We have to know the number of molecules present in 500 g of water.
The answer is: zero molecules present in 500g of water.
Water molecule is H₂O. In water molecule, nitrogen molecule can not be present. Molecular mass of water is 18 g. MOlecular mass of nitrogen molecule is 28 g.
500 g water contains 500/18 number of moles= 27.77 moles of water molecules which contains 27.77 X 6.023 X 10²³ number of water molecules.
There is no existence of N₂ molecule.
