Answer: The correct option is C ( is very hard and burns cleanly).
Explanation:
COAL is a form of rock that is made up of mostly carbon amongst other elements which includes sulphur, nitrogen, hydrogen and oxygen. There are different types of coal which include:
--> anthracite ( 90% carbon)
--> bituminous coal ( 70-90% carbon)
--> lignite ( 60- 70% carbon) and
--> peat (60 % carbon).
Anthracite is the type of coal that contains the highest carbon content ( 90% carbon). This makes it very hard and is often a times referred to as HARD COAL. Anthracite is a higher quality coal for domestic and open fire heating. This is because it contains less impurities than other type of coal and thereby making it to BURN CLEANLY avoiding atmospheric pollution.
Answer:
The number of neutron in the Aluminium Isotope is :
B. 14
Explanation:
Isotopes : These are the atoms which have same atomic number but have different mass number.
<u>This image shows the average atomic mass of Al element because it is in decimals</u>.
Atomic mass = 26.98154
(Note : mass number of single isotope can never be in decimals)
It is the average of mass of different isotopes of Al
Major Isotopes of 
are :
......atomic mass = 26
.......atomic mass = 27
mass of Al given in image(26.98) is nearly equal to mass of 2nd isotope(27)
mass of 
Now calculate the neutron in
Number of neutron = mass number - atomic number
= 27 - 13
Number of neutron = 14
(Atomic mass is same as mass number)
Answer:
Model
Theory
Ellipse
Explanation:
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