The average bond energy (enthalpy) for a C=C double bond is 614 kJ/mol and that of a C−C single bond is 348 kJ/mol. Estimate the
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Answer: Thus ∆H, in kJ/mol, for the dissolution of MgSO₄ is -66.7 kJ
Explanation:
To calculate the entalpy, we use the equation:
where,
q = heat absorbed by water = ?
m = mass of water =
c = heat capacity of water = 4.186 J/g°C
= change in temperature =
Sign convention of heat:
When heat is absorbed, the sign of heat is taken to be positive and when heat is released, the sign of heat is taken to be negative.
The heat absorbed by water will be equal to heat released by
To calculate the number of moles, we use the equation:
Given mass = 5.11 g
Molar mass = 120 g/mol
Putting values in above equation, we get:
0.042 moles of releases = 2.8033 kJ
1 mole of releases =
Thus ∆H, in kJ/mol, for the dissolution of MgSO₄ is -66.7 kJ
Answer:
$4375.64 is the cost for making one ton of the brass sample of mass 1 Tonn.
Explanation:
Mass of the brass = 1 ton = 907185 g
Mass of copper = x
Mass of zinc = y
x + y = 907185, ....[1]
Volume of the brass = V
Density of the brass = D =
Volume of copper = v
Volume of zinc = v'
Density of copper = d =
Density of zinc = d' =
v + v' = V
...[2]
On solving [1] and [2]:
x = 633,419 g
y = 273,766 g
1 g = 0.001 kg
x = 633,419 g = 633.419 kg
y = 273,766 g = 273.766 kg
The price of zinc = $1.80/kg
Price of 273.766 kg of zinc = $1.80/kg × 273.766 kg = $492.78
The price of copper = $6.13/kg
Price of 633.419 kg of zinc = $6.13/kg × 633.419 kg = $3882.86
Cost for making one ton of the brass sample :
$492.78 + $3882.86 = $4375.64