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
Answer:
The acceleration of the snowball is 0.3125
Explanation:
The initial speed of the snowball up the hill, u = 0
The speed the snowball reaches, v = 5 m/s
The length of the hill, s = 40 m
The equation of motion of the snowball given the above parameters is therefore;
v² = u² + 2·a·s
Where;
a = The acceleration of the snowball
Plugging in the values, we have;
5² = 0² + 2 × a × 40
∴ 2 × 40 × a = 5² = 25
80 × a = 25
a = 25/80 = 5/16
a = The acceleration of the snowball = 5/16 m/s².
The acceleration of the snowball = 5/16 m/s² = 0.3125 m/s² .
Answers:
a) 154.08 m/s=554.68 km/h
b) 108 m/s=388.8 km/h
Explanation:
<u>The complete question is written below:
</u>
<u></u>
<em>In 1977 off the coast of Australia, the fastest speed by a vessel on the water was achieved. If this vessel were to undergo an average acceleration of
, it would go from rest to its top speed in 85.6 s. </em>
<em>a) What was the speed of the vessel?
</em>
<em>
</em>
<em>b) If the vessel in the sample problem accelerates for 1.00 min, what will its speed be after that minute? </em>
<em></em>
<em>Calculate the answers in both meters per second and kilometers per hour</em>
<em></em>
a) The average acceleration
is expressed as:
(1)
Where:
is the variation of velocity in a given time
, which is the difference between the final velocity
and the initial velocity
(because it starts from rest).

Isolating
from (1):
(2)
(3)
(4)
If
and
then:
(4)
b) Now we need to find the final velocity when
:
<em></em>
(5)
(6)