Answer : The standard enthalpy of formation of ethylene is, 51.8 kJ/mole
Explanation :
According to Hess’s law of constant heat summation, the heat absorbed or evolved in a given chemical equation is the same whether the process occurs in one step or several steps.
According to this law, the chemical equation can be treated as ordinary algebraic expression and can be added or subtracted to yield the required equation. That means the enthalpy change of the overall reaction is the sum of the enthalpy changes of the intermediate reactions.
The formation reaction of
will be,

The intermediate balanced chemical reaction will be,
(1)

(2)

(3)

Now we will reverse the reaction 1, multiply reaction 2 and 3 by 2 then adding all the equations, we get :
(1)

(2)

(3)

The expression for enthalpy of formation of
will be,



Therefore, the standard enthalpy of formation of ethylene is, 51.8 kJ/mole
Answer:
The questions are incomplete
Explanation:
(b) This question is incomplete. However to calculate the number of moles of CuSO₄ present in the impure sample. The formula below can be used;
number of moles = mass of CuSO₄ present in the impure sample ÷ molar mass of CuSO₄
(c) This question is also incomplete. However, to calculate the mass percentage of CuSO₄ present in the impure sample of CuSO₄, the formula below can be used.
Mass percentage of CuSO₄ =
mass of CuSO₄ present in the impure sample/mass of impure CuSO₄ × 100
Thus, the mass of the impure sample must be measured also since the actual mass of the CuSO₄ present in the impure sample must have been measured before calculating the number of moles.
Answer:
chemical energy into thermal energy
Explanation:
The reaction taking place is as follows
2C₂H₂ + 5O₂ = 4CO₂ + 2H₂O + Heat
In this reaction bonds present in acetylene is broken and new bond present in water and carbon dioxide are formed . In the whole process of bond breaking and bond formation , there is net loss of energy and that energy is released as heat energy .
Thus we can say that in the whole process , chemical energy is converted into heat energy .
Answer:
i dont know what you are saying
Explanation:
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Answer: The Milky Way is a barred spiral galaxy with a diameter between 150,000 and 200,000 light-years (ly).