Equations can be balanced by using the half reaction method. which step should be completed first when using this method? a. inserting the coefficients b. balancing the half reactions. c. identifying the half reactions. d. finding the oxidation states of atoms

The correct answer is Option D.

Explanation:

Half reaction method uses the half cell reactions to balance a chemical equation.

To balance an equation by half reaction method, we first need to find out the oxidation state of the atoms. By this, we can determine which substance is getting oxidized and which is getting reduced.

In oxidation half reaction, the specie looses its electron according to the oxidation state.

In reduction half reaction, the specie gains its electron according to the oxidation state.

Hence, to balance an equation with half reaction method, we first need to find out the oxidation state of atoms.

Thus, the correct answer is Option D.

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