In: Chemistry
A neon sign is made of glass tubing whose inside diameter is 2.5 cm and whose length is 5.5 m. If the sign contains neon at a pressure of 1.73 torr at 37 ∘C, how many grams of neon are in the sign? (The volume of a cylinder is πr2h.) Express your answer using two significant figures.
volume of a cylinder = πr2h
diameter = 2.5 cm then radius is 2.5/2 = 1.25 cm
height(length) = 5.5 m = 550 cm
volume = 3.14*(1.25cm)^2*550 cm
= 2698.4 cm^3
= 2698.4 mL
pressure = 1.73 torr = 0.002276 atm
Temperature = 37 + 273 = 310 K
PV = nRT
0.002276*2.6984 = n*(0.0821)*310
n = 0.000241 moles
molar mass of Neon = 20.18 g mol
mass of Neon = moles * molar mass
= 0.000241*20.18
= 0.00486 g
= 4.9*10^-3 g