A. good conductors - copper, aluminium
b. fair conductors - carbon,human body
c. insulator - paper, wood
<h2>Answer : Law of conservation of mass</h2><h3>Explanation :</h3>
The law of conservation of mass states that in any reaction mass is neither created nor lost it has to remain constant in a system.
In this case, when the reaction setup was done in normal way the mass was lost in surrounding was not considered nor being calculated; whereas when the reaction was studied in a closed system where the gas was collected after the reaction the mass changes was noted down which helped to prove the point of law of conservation of mass and energy.
One can consider an example of soda can where the carbonated drink contains pressurized carbon dioxide gas. when opened the gas bubbles gets lost into the surroundings and we don't measure the mass changes. Instead if the soda can was opened in such a way where the gas evolved was measured then the mass changed would remain the same.
<span>The escape of gas through a small hole in a container is called effusion. This phenomenon happens when the diameter of the hole is small enough compared to the mean free path of the gas particles. This is governed by Graham's Law which states that the rate of effusion is inversely proportional to the molecular weight of the gas.</span>
Answer: 69.72 kg of cryolite will be produced.
Explanation:
The balanced chemical equation is:
To calculate the moles, we use the equation:
moles of 
= 
moles of 
= 
moles of 
= 
As 1 mole of reacts with 6 moles of
166 moles of reacts with = 
moles of
As 1 mole of reacts with 12 moles of
166 moles of reacts with = 
moles of
Thus is the limiting reagent.
As 1 mole of produces = 2 moles of cryolite
166 moles of reacts with = 
moles of cryolite
Mass of cryolite 
= 
Thus 69.72 kg of cryolite will be produced.
Answer:
Collisions between gas particles are elastic; there is no net gain or loss of kinetic energy.
Explanation:
When a gas is paced in a container, the molecules of the gas have little or no intermolecular interaction between them. There is a lot of space between the molecules of the gas.
The gas molecules move at very high speed and collide with each other and with the walls of container.
The collision of these particles with each other is perfectly elastic hence the kinetic energy of the colliding gas particles do not change.
