Answer:
(a) The coefficient of performance of an irreversible refrigeration cycle is always less than the coefficient of performance of a reversible refrigeration cycle when both exchange energy by heat transfer with the same two reservoirs.
Explanation:
According to the Kelvin–Planck statement of the second law of thermodynamics ,it is not possible to construct a device which operates in cycle and does not produce effect on the environment than the production of work.
We know that
Coefficient of performance is the ratio of desired effect to the work input in a cycle.
Given all option is correct but most appropriate option is a.
So the option a is correct
(a) The coefficient of performance of an irreversible refrigeration cycle is always less than the coefficient of performance of a reversible refrigeration cycle when both exchange energy by heat transfer with the same two reservoirs.
I'm pretty sure it's the law of conservation of matter
<span>A metal is one which ionizes easily and gives electrons whencompared to other elements.
So it should have a lower ionization energy.
Hence we would expect element 2 to be a metal.</span>
Answer:
A covalent chemical bond is one in which <u>outer-shell electrons of two atoms are shared so as to satisfactorily fill their respective orbitals</u>.
Explanation:
Covalent bonds are formed between two atoms having their electronegativity difference less than 1.7. In this type of bonding the valence electrons of one atoms forms molecular bond with the valence electrons of another atom. The electrons are mutually shared.
Covalent bond can be non-polar as for example formed between hydrogen and carbon atoms.
Also, covalent bond can be polar in nature as that formed between hydrogen and chlorine atoms because the chlorine atom is more electronegative and hence attracts the electrons more towards itself making density of electrons less on hydrogen atom.
Answer:
ten atoms of hydrogen are present in one mole of caffeine.
Explanation:
Molecular formula of caffiene is given which is C3H10N4O2. It clearly shows that ten atoms of hydrogen are present. One mole is amount equal to one molecular weight of a molecule which is derived from molecular formula. So as moecular formula has ten atoms of hydrogen, one mole of caffeine has 10 atoms of hydrogen.