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.
Nitrogen (around 78%), Oxygen (around 21%), and Argon (around 1%).
Hope this helps :)
The answer is C. Salt and water is a solution
Answer:
Changes in Properties Changes in properties result when new substances form. For instance, gas production, formation of a precipitate, and a color change are all possible evidence that a chemical reaction has taken place. ... Change in Color A color change can signal that a new substance has formed.
Explanation:
The enthalpy change in a reaction is given by-
ΔH°rxn = ∑nΔH°f,products - ∑nΔH°f,reactants
This can be expressed in terms of bond energy as-
ΔH°rxn = BEreactants - BEproducts
Therefore, the calculated bond energy according to the above equation will be-
ΔH°rxn = [ (C-C) + 2(C-O) + 4(C-H) + 2(O-H) ] - [ (C-C) + 2(C-O) + 4(C-H) + 2(O-H) = 0 kJ/mol
<h3>What is enthalpy change?</h3>
Enthalpy change is a measure of the energy emitted or consumed in a reaction. This can be determined using the following equation which involves standard enthalpy of reactant and product formation:
ΔH°rxn = ∑nΔH°f,products - ∑nΔH°f,reactants
<h3>What is bond energy?</h3>
Bond energy is defined as the amount of energy needed to dissociate a mole of molecules into their individual atoms.
Learn more about the Enthalpy Change here:
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