Lead can be prepared from galena (lead II sulfide) by roasting the galena in the presence of oxygen to form lead II oxide and sulfur dioxide. Heating the metal oxide with more galena creates the molten metal and more sulfur dioxide. If we start with 25 mol of PbS, how many moles of SO2 do we create from both steps of the reaction? How many moles of lead do we form? PbS + O2 -> PbO + SO2
PbO + PbS -> Pb + SO2

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