Available online
Description
In this programme Prof. Haynes and Dr. Ross examine some spontaneous reactions to see whether the enthalpy change is related to the direction in which the reaction goes. To see how entropy is invol...ved, Dr. Ross considers a spontaneous transfer of heat energy, and arrives at an expression of the Second Law of Thermodynamics. The programme continues with e film of the determination of the absolute entropy of a substance at 253 K at the National Physical Laboratory, In this determination an adiabatic calorimeter is used to find the variation of specific heat with temperature, from which the entropy of the substance is calculated.
In this programme Prof. Haynes and Dr. Ross examine some spontaneous reactions to see whether the enthalpy change is related to the direction in which the reaction goes. To see how entropy is invol...ved, Dr. Ross considers a spontaneous transfer of heat energy, and arrives at an expression of the Second Law of Thermodynamics. The programme continues with e film of the determination of the absolute entropy of a substance at 253 K at the National Physical Laboratory, In this determination an adiabatic calorimeter is used to find the variation of specific heat with temperature, from which the entropy of the substance is calculated.
| Item code: | S25-; 05 |
|---|---|
| First transmission date: | 18-03-1972 |
| Published: | 1972 |
| Rights Statement: | |
| Restrictions on use: | |
| Duration: | 00:22:46 |
| + Show more... | |
| Producer: | David Jackson |
| Contributors: | R Andon; Len Haynes; Robert Ross |
| Publisher: | BBC Open University |
| Keyword(s): | Absolute entropy; Adiabatic calorimeter; Enthalpy change; Second Law of Thermodynamics; Spontaneous heat transfer |
| Footage description: | Len Haynes introduces the programme. Haynes reacts ferric nitrate with NaOH (a spontaneous reaction). Haynes then demonstrates two other reactions and monitors temperature changes. (Reaction 1 is exothermic, reaction 2 is endothermic). Bob Ross reacts NaOH with water, then ammonium nitrate with water. (Reaction 1 is exothermic, reaction 2 is endothermic). Bob Ross examines the spontaneous transfer of thermal energy from a hot block of metal to a cold block. He explains that this result is one way of stating the Second Law of Thermodynamics. (This is shown on the screen) Len Haynes gives a very brief explanation of the NPL procedure for determining the entropy of a substance. Bob Ross considers the increase in temperature which would be observed in the cold block (above) when thermal energy, q, was transferred to it. Shot of graph which shows how average heat capacity for ether varies with temperature. Commentary by Ross. Ross with a larger than scale tape apart model of the NPL calorimeter. He explains how it works. Film shots of the NPL shows how information on entropy of ether is obtained there. Commentary by Ross. R. Andon of the NPL demonstrates the equipment. Ross with a schematic diagram which shows the processes during the experiment. He explains the principles involved. Film shots of the experiment in progress at NPL. R. Andon perpares the calorimeter. Shots of the equipment being evacuated and coolant tanks being filled. Shots of a computer print-out showing the temperature and energy input. Ross with a similar print-out explains what information it contains. Ross then asks students to calculate the absolute entropy value of ether at 298.15 Kelvin using a similar print-out as data. |
| Master spool number: | 6LT/70440 |
| Production number: | 00521_2176 |
| Videofinder number: | 1773 |
| Available to public: | no |
