Given thath2(g) + f2(g) -> 2hf(g) => ∆h = -546.6 kj . mol-12h2(g) + o2(g) -> 2h20(l) => ∆h = -571.6 kj. mol-1

calculate the value of ∆h for: 2f2(g) + 2h20(l) -> 4hf(g) + o2(g)

The for the reaction is -521.6 kJ.

Explanation:

Hess’s law of constant heat summation states that the amount of heat absorbed or evolved in a given chemical equation remains the same whether the process occurs in one step or several steps.

According to this law, the chemical equation is treated as ordinary algebraic expressions and can be added or subtracted to yield the required equation. This means that the enthalpy change of the overall reaction is equal to the sum of the enthalpy changes of the intermediate reactions.

The chemical equation for the reaction of fluorine and water follows:

The intermediate balanced chemical reaction are:

(1)        ( × 2)

(2)    

The expression for enthalpy of reaction follows:

Putting values in above equation, we get:

Hence, the for the reaction is -521.6 kJ.

first let us lay out the formula for potential

and kinetic energy:

pe = mgh

ke = (mv^2)/2

where: m=mass, v=velocity, g=gravitational

acceleration, h=height

calculating for mass using the known values of

pe:

340j = m (9.81 m/s^2) (50ft) (1m/3.28ft)

m = 2.27 kg

the law of conservation of energy states that

energy is neither created nor destroyed. therefore, the change in kinetic

energy from 50 ft to 35 ft would be equal to the change in potential energy

from 50 ft to 35 ft. however it would be opposite in signs since one is losing

while other is gaining.

ke(35ft) – ke(50ft) = - [ pe(35ft) – pe(50ft]

ke(50ft) = 0 since the brick is initially at rest

ke(35ft) = 340j - 2.27kg (9.81 m/s^2) (35ft)

(1m/3.28 ft)

ke(35ft)

= 102.38 j

a is the answer to this question

explanation: