4fe + 3o2à 2fe2o3 is a balanced equation. what is the charge on each iron (fe) ion in hematite (fe2o3)?

a. +1
b. +2
c. +3
d. +4

The correct answer is Option C.

Explanation:

Oxidation state is the number which is assigned to an element when it gains or looses electrons. If the element gains electron, it will attain a negative oxidation state and if the element looses electrons, it will attain a positive oxidation state.

We take the oxidation state of iron atom be 'x'.

Oxidation state of oxygen atom = -2

Evaluating the oxidation state of iron atom in :

Hence, the correct answer is Option C.

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