Chapter 5

Question 1

What is the definition of pressure in the SI system?

Answer 1

Pressure in the SI system is defined as the pascal, Pa, which equals N/m2.

Question 2

What is the unit of pressure in the common system?

Answer 2

The unit of pressure in the common system is the atmosphere, atm, which is the average air pressure at sea level and equals 101,325 Pa.

Question 3

What is a barometer?

Answer 3

A barometer is an instrument used to measure atmospheric pressure by measuring the difference in the level of liquid mercury between a side exposed to the atmosphere and a side under vacuum.

Question 4

What is the relationship between mm Hg and atm?

Answer 4

1 torr is equal to 1 mm Hg. 760 mm Hg is equal to 1 atm.

Question 5

How is pressure measured in modern instruments?

Answer 5

Pressure in modern instruments is measured using a pressure transducer, which measures the force on a strain gauge attached to a surface that bends under the pressure applied. The force is then converted electronically into a readout of pressure units.

Question 6

The equation of state for an ideal gas.

Answer 6

p: Pressure
V: Volume
T: Temperature
n: Number of Moles
R: Universal Gas Constant
pV = nRT

Question 7

Calculation Units for Systems
SI System:
L atm System:

Answer 7

1. the SI system, p in Pa, V in m3, T in K, and n in moles, R = 8.314 J/mol.K
2. the L atm system, p in atm, V in L, T in K, and n in moles, R = 0.08206 L.atm/mol.K

Question 8

Molar Mass Law

Answer 8

m = n x M
Mass of Given amount of substance (g)
Number of Moles (mol)
Molar Mass