To work this out you do 400÷20=20
Answer:
ΔH of the reaction is -802.3kJ.
Explanation:
Using Hess's law, you can know ΔH of reaction by the sum of ΔH's of half-reactions.
Using the reactions:
<em>(1) </em>Cgraphite(s)+ 2H₂(g) → CH₄(g) ΔH₁ = −74.80kJ
<em>(2) </em>Cgraphite(s)+ O₂(g) → CO₂(g) ΔH₂ = −393.5k
J
<em>(3) </em>H₂(g) + 1/2 O₂(g) → H₂O(g) ΔH₃ = −241.80kJ
The sum of (2) - (1) produce:
CH₄(g) + O₂(g) → CO₂(g) + 2H₂(g) ΔH' = -393.5kJ - (-74.80kJ) = -318.7kJ
And the sum of this reaction with 2×(3) produce:
CH₄(g) + 2 O₂(g) → CO₂(g) + 2H₂O(g) And ΔH = -318.7kJ + 2×(-241.80kJ) =
<em>-802.3kJ</em>
Answer:
The Order is as follow,
C-H < S-H < H-Br < H-Cl
Explanation:
Polarity depends on the electronegativity difference between two atoms, greater the electronegativity difference, greater will be the polarity of bond and vice versa.
Electronegativity Difference between Hydrogen and other given elements are as follow,
1) C-H;
E.N of Carbon = 2.55
E.N of Hydrogen = 2.20
------------
Difference 0.35
2) S-H;
E.N of Sulfur = 2.58
E.N of Hydrogen = 2.20
------------
Difference 0.38
3) H-Br;
E.N of Bromine = 2.96
E.N of Hydrogen = 2.20
-------------
Difference 0.76
4) H-Cl;
E.N of Chlorine = 3.16
E.N of Hydrogen = 2.20
-----------
Difference 0.96
Hence it is proved that the greatest electronegativity difference is found between H and Chlorine in H-Cl, therefore it is highly polar bond and vice versa.
Formula for calculation of neutrons is Mass number - atomic number, here values are given. By putting values in formula 76-35= 41. Number of neutrons 41
