Units Of Measurement

Question 0

International system of units (SI)

Answer 0

Meters, kilos, degrees Celsius

Question 1

American units

Answer 1

Feet, pounds, degrees Fahrenheit

Question 2

1 m =

Answer 2

100 cm = 10^3 mm = 10^6 μm

Question 3

1 g =

Answer 3

10^3 mg = 10^6 μg

Question 4

1 m^3 =

Answer 4

1000 L

Question 5

A waste water effluent of 1000 L/hr contains 6 μg/L. What is the mass in g of mercury discharged per day?

Answer 5

(6 μg/L) x (1 mg/1000 μg) x (1g/1000mg) = 6x10^-6 g/L

(6x10^-6 g/L) x (1000 L /hr) x (24 hr/ day) = 0.144 g/day

Question 6

1 mg/L =

Answer 6

1 ppm

Question 7

1 μg/L =

Answer 7

1 ppb

Question 8

Concentration units for gases

Answer 8

1) volumetric terms (ppmv)
2) percent by volume (%)
3) mass per unit volume (mg/m^3, μg/m^3)

Question 9

Conversion for gases between ppmv & percent by volume (%)

Answer 9

1 ppmv= 10^-4 %

Question 10

Express 0.8 ppmv as percent by volume (%)

Answer 10

1 ppmv/ 10^-4 = 0.8 ppmv/ X,

X= 0.8 x 10^-4 %

Question 11

Converting btw ppmv & mg/m^3 for gases

Answer 11

Mg/m^3 = ((mol weight x ppmv)/ 22.414) x (273.15/actual temp) x (actual pressure/1 ATM)

Question 12

Standard temperature and pressure (STP):

Answer 12

0 degrees Celsius & 1atm

Question 13

Convert the concentration of ozone (O3) at 0.08 ppmv to mg/m^3, at 25C, 1atm, mol weight of O3 = 48 g/mol

Answer 13

Mg/m^3= ((48 x 0.08)/22.414) x (273.15/273.15 +25) x (1atm/1atm)

=0.157 mg/m^3

Question 14

The Idea Gas Law: PV = nRT

Answer 14

P: pressure (ATM)
V: volume (L)
n: mass (mol)
R: ideal gas constant (0.082056 L x ATM x K^-1 x mol^-1)
T: temperature (K)

Question 15

1 mol of an ideal gas occupies what volume?

Answer 15

22.414 L

Question 16

Calculate the mass (g) of SO2 within a volume of 2m^2 at 20C & 1.2 ATM

• mol weight of SO2: 64g/mol
• temp: 20C + 273 = 293K
• volume: 2m^3 = 2000L

Answer 16

n= PV/RT, (1.2 ATM x 2000L)/ (0.08205 LxatmxK^-1xmol^-1x 293K)
n= 99.83 moles
99.83 mol x ((16x2)+32)g/mol = 6389g