Physical Chemistry Answers

Two identical vessels are connected by a tube with a valve letting the gas pass from one vessel into the other is the pressure diff. is greater than or equal to 1.10 atm. Initially there was a vacuum in one vessel while the other contained ideal gas at a temperature t1=27 degree Celsius and pressure p1=1.00 atm. THen both the vessels were heated to a temp t2=107 degree celsius. Up to what value will the pressure in the first vessel increase?

In order to initiate combustion in solids materials, it is usually necessary to raise their temperature by means of an external heat source. Under certain conditions however some materials may generate the necessary heat internally. Give two examples of materials that can exhibit this phenomenon. In each case state how internal heating arises outline the precautions that should be taken when they are stored to prevent combustion occurring

a.List other chemical reactions that can result in heat being produced to such an extent that ignition may occur

b. A fire quiet often follows a change to an industrial process. Give an example of such a change that could result in self heating occurring

a. Contact between two moving surfaces or one moving surface and a stationery one, can lead to the production of electrostatic chargers. List the measures that can be taken to reduce the risk of a fire occurring as a result of a build up of such charges

b. Friction is also common source of ignition in industrial workplaces and is again associated with movement. Explain concisely the difference between friction and electrostatic as a source of ignition

c. List measures that may be taken to reduce the risk of a fire occurring as a result of the build up of heat by friction.

a. What are two properties that a material must have for spontaneous heating to occur under certain conditions

b. in order to initiate combustion in solids materials, it is usually necessary to raise their temperature by means of an external heat source. Under certain conditions, however some materials may generate the necessary heat internally. Give two examples of materials that can exhibit this phenomenon. In each case state how internal heating arises and outline the precautions that should be taken when they are stored to prevent combustion occurring.

a. Name the three mechanism relating to the spread of heat by fire and give a practical fire related example of a situation in which each of these would occur
b. What is the inverse square law and how does it relate to fire safety?outline a factor other than spread of heat where the inverse square law also impacts on fire safety in premise.
c.Discuss the properties of glass with respect to transmitted heat and the implications for glazing on escape routes