Answer:
This element is Rubidium (Rb) and has an average atomic mass of 85.468 u
Explanation:
The average mass of an element is calculated by taking the average of the atomic masses of its stable isotopes.
The enitre atomic mass = 100 % or 1
⇒ this consists of X-85 with 72.17 % abundance with atomic massof 84.9118 g/mol
72.17 % = 0.7217
⇒ this consists of X-87 with 27.83 % abundance with atomic mass of 86.9092 g/mol
27.83 % = 0.2783
To calculate the mass of this isotope we use the following:
0.7271 * 84.9118 + 0.2783 * 86.9092 =85.468 g/mol
This element is Rubidium(Rb) and has an average atomic mass of 85.468 u
Answer:
35.1 kJ/mol is the expected value for the heat of sublimation of acetic acid.
Explanation:
..[1]
Heat of vaporization of acetic acid = 
..[2]
Heat of fusion of acetic acid = 
Heat of sublimation of acetic acid = 
..[3]
[1] + [2] = [3] (Hess's law)
35.1 kJ/mol is the expected value for the heat of sublimation of acetic acid.
Answer:
Total Energy of the electrons
Explanation:
An atom in an excited state is when the total energy of electrons can be lowered by transferring molecule(s) over to different orbitals. in an excited state atom, not all electrons are at the lowest energy levels
Answer: primary colors are those you can't get by mix in other colors. They are red, blue, and yellow. secondary colors come from mixing two primary colors.
We determine the limiting reactant by using the moles present in the equation and the actual moles.
According to equation, ratio of Fe₂O₃ : Al = 1 : 2
Actual moles of Fe₂O₃ = 187.3 / (56 x 2 + 16 x 3)
= 1.17
Actual moles of Al = 94.51 / 27
= 3.5
Fe₂O₃ is limiting. Fe₂O₃ required:
(moles Al)/2 = 3.5/2 = 1.75
Moles to be added = 1.75 - 1.17
= 0.58
Mass to be added = moles x Mr
= 0.58 x (56 x 2 + 16 x 3)
= 92.8 grams
