Answer: Orbits are elliptical, Sun is in focal point of the ellipse.
Explanation:
Orbits are not perfect circles. Distance of Earth from Sun is between
147 million kilometres - 152 million kilometres. When Earth is in closest point of the Sun it moves faster tant in the point which is most far away from Sun.
Kepler´s Laws give more information.
Volumen = constant => P/T = constant
T1 = 21°C + 273.15 = 294.15 k
P1 = 0.82 atm
T2 = - 3.5°C + 273.15 = 269.65 k
P2 = ?
P2 / 269.65k = 0.82atm / 294.15k
P2 = [0.82atm / 294.15k] * 269.65kg = 0.75 atm
The pure substance of water mixes with the waste. The waste does not dissolve into the water, therefore it is a mixture.
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