Let the total mass of compound is 100g
The mass of each element will be
Al = 22.10 g
P = 25.40 g
O = 52.50 g
In order to determine the molecular formula we will calculate the molar ratio of the given elements
Atomic weight of Al : 27 g/ mol
Atomic weight of P : 3 1g /mol
Atomic weight of O : 16 g /mol
Moles of Al = mass / atomic mass = 22.10 / 27 = 0.819
Moles of P = mass / atomic mass = 25.40/ 31 = 0.819
Moles of O = mass / atomic mass = 52.50/ 16 = 3.28
Now we will divide the moles of each element with the lowest moles obtained to obtain a whole number ratio of moles of each element present
moles of Al = 0.819 / 0.819 = 1
moles of P = 0.819 / 0.819 = 1
moles of O = 3.28 / 0.819 = 4
So the empirical formula will be : AlPO4
From reliable sources in the web, it may be searched that the specific heat of copper is approximately equal to 0.385 J/gC. The amount of heat that is required to raise a certain amount by certain number of degrees is given in the equation,
H = mcpdT
where H is heat, m is mass, cp is specific heat, and dT is temperature difference. Substituting the known values,
186,000 J = (m)(0.385 J/gC)(285C)
m = 1695.15 g
Answer: at relatively low temperatures.
Explanation:
According to Gibbs equation;
= Gibb's free energy change
= enthalpy change
T = temperature
= entropy change
A reaction is spontaneous when = Gibb's free energy change is negative.
Thus 
Thus the reaction is spontaneous or is negative only when 
Thus the reaction is spontaneous at relatively low temperatures
For example, monosaccharides:
C₆H₁₂O₆
aldohexoses
ketohexoses
C₃H₆O₃
aldotrioses
ketotrioses
and many others
