In order to verify the law of conservation of mass, a student mixed 6.3 g of sodiumcarbonate and 15 g of ethanoic acid in a conical flask. After experiment, he
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weighed the flask again. The weight of the residue in the flask was only 18g. He
approached the teacher who guided him to carry the experiment in a closed flask
with a cork. There was no difference in weight of the flask before and after the
experiment.
Answer the following questions
What was the mistake committed by the student?
i. Why did not the two weights match earlier?
iii. How did the teacher help him?
iv. What lesson was learnt by the students?
Answers
Explanation:
Following are the Fire fighting equipments which are used onboard ships:
1. Fire Retardant Bulkhead: Different Class of bulkhead such Class-A, Class-B and Class-C are used on board ship for construction of bulkhead in areas like accommodation, machinery space, pump room etc. The main applications of such bulkhead are to contain or restrict the spread of fire in sensitive areas.
2. Fire doors: Fire doors are fitted in fire retardant bulkhead to provide access from the same. They are self closing type doors with no hold back arrangement.
3. Fire Dampers: Dampers are provided in the ventilation system of cargo holds, engine room, accommodation etc. in order to block out excessive oxygen supply to the fire. For this, it is necessary that open and shut position clearly marked for fire dampers.
4. Fire Pumps: As per regulation, a ship must have main fire pump and an emergency power pump of approved type and capacity. The location of the emergency fire pump must be outside the space where main fire pump is located.
5. Fire Main Piping and Valves: The Fire Main piping which is connected to the main and emergency fire pump must be of approve type and capacity. Isolation and relief valves must be provided in the line to avoid over pressure of the same.
6. Fire Hose and Nozzles: Fire hoses with length of at least 10 meters are used in ships. Number and diameter of the hoses are determined by the classification society. Nozzle of diameters 12 m, 16 m and 19 m used on ship are of dual purpose types- Jet and spray mode.
7. Fire Hydrants: Fire hoses are connected to fire hydrants from which the water supply is controlled. They are made up of heat retardant material to get least affected from the sub zero temperatures and also to ensure that hoses can be easily coupled with them.
8. Portable Fire Extinguishers: Portable fire extinguishers of CO2, Foam and Dry Chemical Powder are provided in accommodation, deck and machinery spaces carried along with number of spares as given by the regulation.