Answer : The correct answer is A. Nuclear reactors using Pu-239
B. burning coal
The sources which are not renewable are known as "non- renewable sources of energy .
Non - renewable sources are those which get expired after rapid use and can never be reproduced . These sources replenishes in very long time . Examples : Coal , petrol or fuels etc .
1) Nuclear reactors using Pu-239 : Nuclear reactors uses radioactive elements like uranium , plutonium etc , which are present in limit . after frequent use of these elements , they will vanish off , Hence we can say nuclear reactors are Non renewable source of energy .
2) Burning coal : Coal is used as one of the major source of fuel . On rapid utilization of coal they will finished from earth . It takes thousand of year for formation of coal . Hence , it is a Non -renewable source .
3) Photo-voltaic cell: These are cells which used solar energy . Solar energy is obtained from sun . Hence solar energy is renewable source of energy so is the photo voltaic cell .
4) Geothermal energy : Geothermal energy is source of energy that is extracted from earth's thermal energy . Since thermal energy of earth is present in very large amount and can be reproduced , hence it renewable source of energy .
5)Wind energy : Wind energy is source of energy that is obtained from wind. And wind is renewable source so the wine energy too .
Consequently , we can say only two of them " Nuclear reactors and burning of coal " are Non renewable force of energy .
Answer:
B) The term "inert" was dropped because it no longer described all the group 8A elements.
Explanation:
Inert elements in chemistry simply refers to elements that are chemically inactive and are not expected to form any compounds. this is the general belief for the group 8 elements as they all have complete duplet/octet configurations (and ideally, they ought to be very stable with no tendency to form compounds by participating in the loss and gain of electrons). However the discovery of compounds like xenon tetrafluoride (XeF4) proved this to be wrong.
Again, the reason the term - inert gses was droppedis beacause this term is not strictly accurate because several of them do take part in chemical reactions.
After dropping the term - Inert gases, they are now referred to as noble gases.
The average atomic mass is calculated by the expression:
Average atomic mass = Σzₓ(Aₓ)
where zₓ is the relative abundance of an isotope and Aₓ is the atomic mass of the isotope.
We calculate the mass of the isotope as follows:
10.81 = .1980 (10.012938) + .8020 (x)
x = 11.00 -----------> mass of the isotope
Answer:
Both the motion of the particles in the substance and the temperature of the substance increase.
