Answer:
Explanation:
13 ) symbol of enthalpy change = Δ H .
14 ) enthalpy change is nothing but heat absorbed or evolved .
During fusion enthalpy change
Δ H .= m Lf , m is mass and Ls is latent heat of fusion
During evaporation, enthalpy change
Δ H .= m Lv , m is mass and Lv is latent heat of evaporation
during temperature rise , enthalpy change
Δ H = m c Δ T
In case of gas , enthalpy change can be calculated by the following relation
Δ H = Δ E + W , Δ E is change in internal energy , W is work done by gas.
15 ) When enthalpy change is negative , that means heat is released to the environment .So reaction is called exothermic .
when heat is absorbed enthalpy change is positive . Reaction is endothermic.
Answer
Do you think that the mole should be considered a base unit in the SI system?
The mole is not a base unit on a par with the six property base units; it cannot be used in significant physical–chemical comparisons until the subscript parameter p in mole-of-Ep has been given a certain “value”."
Explanation:
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:
Dichloromethane
Explanation:
As we know the atomic number given belongs to following elements, i.e.
Atomic # Element M.Mass
1 Hydrogen 1 g.mol⁻¹
6 Carbon 12 g.mol⁻¹
17 Chlorine 35.5 g.mol⁻¹
Also the molecular formula of Dichloromethane is,
= CH₂Cl₂
Putting molar masses of each element,
= (12)₁ + (1)₂ + (35.5)₂
= 12 + 2 + 71
= 85 g.mol⁺¹
Result:
Hence the only possible structure containing 5 atoms is Dichloromethane.
