C9H20 + 14O2 --> 9CO2 + 10H2O
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.
When comparing single bonds between atoms of comparable types, the stronger the bond is, the bigger the atom, the weaker it is.
The length of the X-H bond lengthens while the strength of the bond shortens with increasing halogen size (F-H strongest, I-H weakest). When comparing single bonds between atoms of similar sorts, the larger the atom, the weaker the bond. It can be explained by the fact that less energy is required to break the bond the bigger the atom's atomic size. The force of attraction from the nucleus to the outermost orbit will be less for iodine since it has a larger atom than the other elements in the group.
Learn more about single bonds here-
brainly.com/question/16626126
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Elements because elements make up atoms which make up everything
