The average number of televisions per family is numbered in the tens.
1 answer:
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Answer:
One complete revolution around a circular path.
Explanation:
Let us take the case of a car moving in a circular track of radius r metres.
In one revolution, the car covers the length(distance) equal to the perimeter of the circle.
In this case, distance traveled = 2r metres
But after one complete revolution, the car reaches the same position as it was at the beginning of the motion.
Hence, the initial and final points coincide or the car hasn't changed it's position w.r.t the initial point.
So in this case, the displacement is zero.
Hence, revolution of a car around a circular path is an example of an object traveling a distance but having no displacement.
Answer : The standard enthalpy of formation of ethylene is, 52.4 kJ
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 equation, we get :
(1)
(2)
(3)
The expression for enthalpy of formation of will be,
Therefore, the standard enthalpy of formation of ethylene is, 52.4 kJ