Answer is: Ksp for calcium sulfate is 2.36·10⁻⁴.
Balanced chemical reaction (dissociation):
CaSO₄(s) → Ba²⁺(aq) + SO₄²⁻(aq).
m(CaSO₄) = 0.209 g.
n(CaSO₄) = m(CaSO₄) ÷ M(CaSO₄).
n(CaSO₄) = 0.209 g ÷ 136.14 g/mol.
n(CaSO₄) = 0.00153 mol.
s(CaSO₄) = n(CaSO₄) ÷ V(CaSO₄).
s(CaSO₄) = 0.00153 mol ÷ 0.1 L = 0.0153 M.
Ksp = [Ca²⁺] · [SO₄²⁻].
[Ca²⁺] = [SO₄²⁻] = s(CaSO₄).
Ksp = (0.0153 M)² = 2.36·10⁻⁴.
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
Answer:
C. They don't react with other elements to form compounds
Explanation:
The elements in Group 18 of the periodic table are called "inert", or noble gases.
These elements have their valence shell (the outermost shell of the atom) full of electrons, so they do not gain/give off electrons, and therefore, they do not react with other elements, so they do not form compounds.
In fact, normally the elements try to gain/give off electrons in order to fullfill their outermost shell (the valence shell). For instance, an atom that has 1 electron only in its valence shell, try to "give away" this electron in order to have its outermost shell completed. On the other hand, an atom which has 7 electrons in its valence shell tries to "gain" one electron in order to fullfill the valence shell.
Noble gases, instead, have already 8 electrons in their valence shell, so their valence shell is already completed, therefore they do not react with other elements, and therefore they are called "inert".
Answer:
4.704J
Explanation:
The following data were obtained from the question:
m = 0.080kg
h = 6.0m
g = 9.8m/s^2
P.E =?
P.E = mgh
P.E = 0.08 x 9.8 x 6
P.E = 4.704J
Therefore, the potential energy of the robin is 4.704J
