Answer:
Option (B) is correct.
Explanation:
Given that the molecules of hydrogen gas (
) react with molecules of oxygen gas (
) in a sealed reaction chamber to produce water (
).
The governing equation for the reaction is
From the given, the only fact that can be observed that 2 moles of and 1 mole of reacts to produce 2 moles of .
As the mass of 1 mole of 
grams ... (i)
The mass of 1 mole of 
grams ...(ii)
The mass of 1 mole of 
grams (iii)
Now, the mass of the reactant = Mass of 2 moles of + mass 1 mole of
[ using equations (i) and (ii)]
grams.
Mass of the product = Mass of 2 moles of
[ using equations (iii)]
=36 grams
As the mass of reactants = mass of the product.
So, mass is conserved.
Hence, option (B) is correct.
Answer: A. Work is done on the system and heat is transferred from the system for a net decrease in internal energy.
Explanation:
A refrigerator is a device which dispenses heat from the close system to a warmer area or in the surrounding. By dispensing the heat the internal temperature of the refrigerator drops. The system of refrigerator violates the second law of thermodynamics. As it performs the work to cool the region instead of heating the region. The work is done on the system and the internal energy decreases and the heat energy is liberated to the surrounding area. A refrigerator is an open system.
To solve this problem we will apply the concepts related to the kinematic equations of linear motion. From there we will define the distance as the circumference of the earth (approximate as a sphere). With the speed given in the statement we will simply clear the equations below and find the time.
The circumference of the earth would be
Velocity is defined as,
Here 
, then
Therefore will take 167463.97 s or 1 day 22 hours 31 minutes and 3.97seconds
I think the correct answer from the choices listed above is option C. As an object sinks in a fluid, the buoyant force increases before it is submerged and as the object is submerged the buoyant force stays the same. This can be explained by Archimedes principle.<span />
Could be with a click of a finger depending how strong the light of the sun is
