Water (H20) can decompose in an endothermic reaction to form hydrogen (H2) and oxygen (O2). 2H20(1) - 2H2(g) + O2(g)
Forming the bonds in 1 mole of hydrogen molecules releases 436 kJ of energy. Forming the bonds in 1 mole of oxygen molecules
releases 495 kJ of energy.
When 2 moles of water decompose and form hydrogen and oxygen gases, 475 kJ of energy are absorbed from the surroundings.
How much energy is absorbed when the bonds are broken in 1 mole of water?
OA. 1,842 kJ
B. 921 kJ
C. 703 kJ
OD. 456 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

c) should be the answer.