Answer:
RIGHT
Explanation:
given,
mass of box = 250 kg
speed of the truck = 25 m/s
static friction µs = 0.7
g = 10 m/s²
to find direction of friction on the box
truck is moving in left direction and suddenly in front of truck a car stops then the driver hit the brake hard so at that moment the box on the trailer will have the tendency to move left so to oppose its movement friction force will be on RIGHT
Answer : The change in enthalpy of the reaction is, -310 kJ
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 given main reaction is,
The intermediate balanced chemical reaction will be,
(1)
(2)
(3)
Now we will reverse the reaction 1 and multiply reaction 1 by 2, reaction 2 by 2 and reaction 3 by 3 then adding all the equations, we get :
(1)
(2)
(3)
The expression for enthalpy of formation of will be,
Therefore, the change in enthalpy of the reaction is, -310 kJ