Answer:
4.09×10⁻³ is the mole fraction of sucrose
Explanation:
Mole fraction = Moles of solute or solvent/ Total moles
Let's convert the mass to moles (mass / molar mass)
38.6 g / 342 g/m = 0.113 moles of sucrose
495 g / 18 g/m = 27.5 moles of water
Total moles = 0.113 m + 27.5 m = 27.0613 moles
Mole fraction of sucrose = Moles of sucrose / Total moles
0.113 m / 27.0613 moles = 4.09×10⁻³
Answer:
ΔH = - 272 kJ
Explanation:
We are going to use the fact that Hess law allows us to calculate the enthalpy change of a reaction no matter if the reaction takes place in one step or in several steps. To do this problem we wll add two times the first step to second step as follows:
N2(g) + 3H2(g) → 2NH3(g) ΔH=−92.kJ Multiplying by 2:
2N2(g) + 6H2(g) → 4NH3(g) ΔH=− 184 kK
plus
4NH3(g) + 5O2(g) → 4NO(g) +6H2O(g) ΔH=−905.kJ
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2N2(g) + 6H2(g) + 5O2(g)→ 4NO(g) + 6H2O(g) ΔH = (-184 +(-905 )) kJ
ΔH = -1089 kJ
Notice how the intermediate NH3 cancels out.
As we can see this equation is for the formation of 4 mol NO, and we are asked to calculate the ΔH for the formation of one mol NO:
-1089 kJ/4 mol NO x 1 mol NO = -272 kJ (rounded to nearest kJ)
1- evaporation 2- transpiration 3-condensation 4- precipitation
Hey there!
Molar mass C2H6O = 46.0684 g/mol
Number of moles:
n = mass of solute / molar mass
n = 70.6 / 46.0684
n = 1.532 moles
Therefore:
M = number of moles / volume ( L )
M = 1.532 / 2.25
= 0.680 M
Hope that helps!