A student breaks a thermometer and spills most of the mercury (Hg) onto the floor of the laboratory
that measure 15.2 m long, 6.6 m wide and 2.4 m high.
a) (1 mark) Calculate the volume of the room in m3 and L.
b) (2 marks) If the vapour pressure of mercury at 293.15 K is 1.7 × 10-6 atm, calculate the mass of
mercury vapour (in grams) in the room at 293.15 K.
c) (2 marks) Does the concentration (mg Hg/m3 air) of mercury vapour in the room exceed the air
quality regulation of 0.050 mg Hg/m3 of air?
d) (1 mark) One way to treat small quantities of spilled mercury is to spray sulfur powder over the
metal. Suggest briefly a why this is effective.
So for a i did dimensional analysis.
for B i did n=pv/rt. Not sure how to approach c or d
c.
From b you know mols. grams Hg = mols Hg x atomic mass Hg. That gives you grams/m^3 and compare that with the standard of 0.050 mg/m3.
d.
Hg + S ==> HgS. HgS is a black insoluble solid.
a) To calculate the volume of the room, we will multiply its dimensions: length, width, and height.
Volume (m^3) = Length (m) * Width (m) * Height (m)
Volume (m^3) = 15.2 m * 6.6 m * 2.4 m
To convert m^3 to L (liters), we need to multiply by 1000 because 1 m^3 is equal to 1000 L.
Volume (L) = Volume (m^3) * 1000
b) To calculate the mass of mercury vapor in the room, we need to use the ideal gas law equation: PV = nRT, where P is the pressure, V is the volume, n is the number of moles, R is the gas constant, and T is the temperature.
First, we need to calculate the number of moles of mercury vapor using the given vapor pressure value (P), the ideal gas law constant (R), and the temperature (T in Kelvin).
n = PV / RT
n = (1.7 × 10^-6 atm) * (Volume (m^3) * 1000 L/m^3) / (R * Temperature (K))
The molar mass of mercury (Hg) is 200.59 g/mol, so we can calculate the mass of mercury vapor:
Mass (g) = n * Molar Mass (g/mol)
c) To determine if the concentration of mercury vapor exceeds the air quality regulation, we need to compare the calculated concentration (mg Hg/m^3) to the regulation limit (0.050 mg Hg/m^3).
d) To treat small quantities of spilled mercury, one effective method is to spray sulfur powder over the metal. Sulfur reacts with mercury to form a non-volatile compound called mercuric sulfide (HgS), which is less harmful and easier to clean up. The sulfur powder helps to absorb and neutralize the mercury, preventing its further release into the air.