It is a compound because a compound is two or more different elements chemically combined.
I'm not sure I'm sorry for that but I found this http://www.chem4kids.com/files/atom_ions.html
The answer is: C. 0.00427 m.
A) 1 km = 1000000 mm.
d = 0.0000427 km · 1000000 mm/km.
d = 47.7 mm.
B) 1 hm = 100000 mm.
d = 0.000427 hm · 100000 mm/hm.
d = 42.7 mm.
C) 1 m = 1000 mm.
d = 0.00427 m · 1000 mm/m.
d = 4.27 mm.
D) 1 cm = 10 mm.
d = 4.27 cm · 10 mm/cm.
d = 42.7 mm.
Millimeter (abbreviated: mm, a thousandth part of metar) is an unit of distance in the metric system.
your answer is <u>B. Arrhenius base</u>
<u>Answer:</u> The correct statement is low temperature only, because entropy decreases during freezing.
<u>Explanation:</u>
The relationship between Gibb's free energy, enthalpy, entropy and temperature is given by the equation:
Where,
= change in Gibb's free energy
= change in enthalpy
T = temperature
= change in entropy
It is given that freezing of methane is taking place, which means that entropy is decreasing and 
is becoming negative. It is also given that the reaction is an exothermic reaction, this means that the is also negative.
For a reaction to be spontaneous, must be negative.
![-ve=-ve-[T(-ve)]\\\\-ve=-ve+T](https://tex.z-dn.net/?f=-ve%3D-ve-%5BT%28-ve%29%5D%5C%5C%5C%5C-ve%3D-ve%2BT)
From above equations, it is visible that will be negative only when the temperature will be low.
Hence, the correct statement is low temperature only, because entropy decreases during freezing.
