Convert 1.67 x10^24 atoms of carbon to moles of carbon

1) Set up your equation. Multiply 1.67× 10^24 atoms by 1 mol of carbon, and divide by 6.022×10^23 atoms of carbon (Avogadro's number). The atoms cancel out and will give you the answer in mols of carbon (Remember, 1 mol = 6.022×10^23 atoms).

1.67×10^24 atoms of carbon × 1 mol of carbon

                                                   6.022×10^23 atoms of carbon

= 0.277317 mol of carbon -> round to 3 sig figs!

Answer = 0.277 mol of carbon

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