1. How is static electricity prevented in rubber conveyor belts?
CARBON IN THE RUBBER POLYMER TO MAKE IT CONDUCTIVE
2. In this graph what must the temperature units be?
AS THE LINE GOES TO ZERO THE UNITS MUST BE KELVIN
3. This is a graph of pressure against temperature for which propellant in an aerosol can?
THIS LINE IS FOR PROPANE VAPOUR IN THE PRESENCE OF LIQUID PROPANE
4. The graph in question 3 shows the pressure line reaching zero at -42 ºC. What happens to the propellant vapour at that temperature?
THE VAPOUR CONDENSES INTO THE LIQUID PHASE
5. Why are storage tanks for liquified propellants painted white?
TO PREVENT OVERHEATING IN BRIGHT SUNLIGHT BY REFLECTING MOST OF THE SOLAR RADIATION
6. This diagram shows 3 cans filled with nitrogen propellant. When the can is almost empty the pressure is 3 bar.
Estimate the pressure for the full and half full can.
THE MIDDLE CAN GAS VOLUME IS ABOUT HALF OF THE NEARLY EMPTY CAN SO THE PRESSURE WILL BE ABOUT 6 BAR.
THE FULLEST CAN IS ABOUT HALF THE VOLUME OF THE MIDDLE CAN SO THE PRESSURE WILL BE ABOUT 12 BAR
7. Which of these are correct descriptions for the nitrogen propellant in the can?
LIQUIFIED VOLATILE REACTIVE INERT VAPOUR IDEAL
NITROGEN IS INERT AND IT IS AN IDEAL GAS (IT OBEYS THE GAS LAWS)
8. Aerosols must not produce spray droplets less than 10 microns diameter. Why not?
PARTICLES SMALLER THAN 10 MICRONS CAN REACH THE ALVEOLI IN THE LUNGS.
9. What type of radiation is absorbed by propane gas?
10. Why are flammable gas sensors placed near the ground in aerosol filling buildings?
PROPANE AND BUTANE HAVE LARGE ORGANIC MOLECULES AND A HIGHER DENSITY THAN AIR. THESE GASES SINK IN AIR. THEY HAVE NO ODOUR. WHEN GASES ARE USED FOR HEATING AND COOKING A STENCHANT IS ADDED TO MAKE THEM SMELL UNPLEASANT. THIS IS NOT POSSIBLE IN AEROSOLS.
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