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:
19.9 moles
Explanation:
Each mole has 6.02 x 10^23 many atoms. This number is commonly known as "Avogadro's Number."
In this problem, we have 1.2 x 10^25 atoms of phosphorus.
Thus, (1.2 x 10^25)/(6.02 x 10^23) is the number of moles in 1.20 x 10^25 many atoms of phosphorus.
(1.2(10^25))/(6.02(10^23))
19.9 moles.
Options are;
(A) H-O bonds break as H-H and O-O bonds form.
(B) Hydrogen bonds between H2O molecules are broken.
(C) Covalent bonds between H2O molecules are broken.
(D) Ionic bonds between H+ ions and OH− ions are broken.
(E) Covalent bonds between H+ ions and H2O molecules become more effective.
Answer:
B: Hydrogen bonds between H2O molecules are broken.
Explanation:
When water is changing from liquid form to vapour form, it's molecules move at a faster rate. This is because the bonds between the molecules have been broken as a result of the heat that converts the liquid to vapour.
And the type of bond that forms water molecules is hydrogen bonds.
Thus, hydrogen bonds are broken when converting from liquid to vapour phase.
Heat released : 79086 J
<h3>Further explanation</h3>
Condenses :
1. phase change (gas - liquid) : heat of vaporization (ΔH vap for water = 2260 J/g)
2. cools from 100 - 10 : (Q=m.cΔT)
1. Q=m.ΔH vap
2. Q=mc.ΔT(c water = 4.18 J/g C)
Q tot = 67800 + 11286 = 79086 J