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:
Explanation:
Given data:
Mass of the paper clip, 
Kinetic energy, 
Let the velocity of the paper clip when it is thrown be <em>v</em>.
Thus,
(rounding to nearest tenth)
Answer:
The efficiency is 0.33, or 33%.
Explanation:
From the thermodynamics equations, we know that the formula for the efficiency of a heat engine is:
Where η is the efficiency of the engine, Q_1 is the heat energy taken from the hot source and Q_2 is the heat energy given to the cold object. So, plugging the given values in the formula, we obtain:
This means that the efficiency of the heat engine is 0.33, or 33% (The efficiency of an engine is dimensionless).
The outer surface of the glass expands faster than the inside surface since glass is a fairly good thermal insulator. The outer surface tries to expand without the inner surface doing so at the same time. This is the secret of Pyrex glass. It is more conductive to heat and the inner and outer surface expand (and contract) at the same time.
