Homework #1 Material

Reading Assignment: All of Chapter 1.

Key Ideas:

(1) Definitions

System

Surroundings

Boundary

Isolated system

Closed System

Open system

Properties

Extensive Properties

Intensive PropertiesSpecific Properties

State of a system

ProcessAdiabatic, Isothermal and Isobaric Processes

Phase

Pure substance

(2) Units, Dimensions and Conversions

Fundamental (primary) dimensions (mass, length and time)Arbitrary standards versus operational definitions

Velocity

Acceleration

Force (and the definition of the Newton)

Pressure (and the definition of the Pascal)Thermodynamic pressureGauge pressureBarometer and relation of pressure to height of a mercury column (cm Hg or in Hg)

Other units for pressure (PSIA, atm, bar, kPa, MPa)

Energy (and the definition of the Joule)Other units for energy (BTU, cal, Pa m3 , ft lbf)

Power (and the definition of the Watt)

TemperatureFahrenheit and centigrade scalesAbsolute scales: the Rankine and Kelvin ScalesConversion between scales

MolesThe gram mole and Avogadro's numberMolecular weightThe kilogram mole (kmol) The pound mole (lb mol)

The English systems of unitsAbsolute, gravitational and mixedThe conversion factor gc

Thermodynamics Homework #1

1. A pressure gauge reads 23.1 in Hg (inches of mercury) vacuum (i.e. -23.1 in Hg gauge). The barometer reads 76.0 cm Hg. What is the pressure (in psia) in the tank to which the pressure gauge is connected? What is this pressure in kPa?

2. A new absolute temperature scale is proposed that has exactly 150 degrees between the freezing point and normal boiling point of water.

a. What is the temperature on the new scale at the freezing point of water?

b. What is the temperature on the new scale at the normal boiling point of water?

c. Develop a relation between T on the new scale and T on the Kelvin scale.

3. The value of the universal gas constant is 1.986 BTU/lb molR. What is its value in cm3bar/mol K?

4. What is

a. 5 ft3 in m3 ?

b. 20 miles/hr in ft/s?

c. 10 cm3 atm in kJ?

d. 1 cal/g C in BTU/lb F? (note 1 cal = 4.1868 J)

e. 100 F in C? in R? in K?

5. Problem 1.9 in your text

6. Problem 3.7 in your text (3.7 is not a misprint)

Answers to Homework Set #1

(1) 3.35 psia, 23.1 kPa (2) 409.5, 559.5, T=1.5 T(K)

(3) 83.15

(4) (a) .142 (b) 29.3 (c) .001013 (d) 1 (e) 37.8, 560, 311

(5) (a) 579.4, 240.2, 360.4, 880.2 (b) 24.8, 1.79, 2.94, 1.13

(6) (a) .1879 (b) 260 (c) .1557