Answer:
The work done and heat absorbed are both -8,1 kJ
Explanation:
The work done in an isobaric process is defined as:
W = -P (Vf - Vi)
Where P is pressure ( 10 atm)
Vf = 10 L
Vi = 2 L
Thus, <em>W = -80 atm×L ≡ -8,1 kJ</em>
This is the work done in expansion of the gas. As the gas remains at the same temperature, there is no change in internal energy doing that all work was absorbed as heat.
I hope it helps!
Answer: 353.6 g.
Explanation:
1) Word equation (given)
Sodium phosphate + calcium choride → sodium chloride + calcium phosphate
2) Balanced chemical equation
2 Na₃PO₄ +3 CaCl₂ → 6 NaCl + Ca₃(PO4)₂
3) Mole ratio
2 moles Na₃PO₄ : 3 moles CaCl₂ : 6 moles NaCl : 1 mole Ca₃(PO4)₂
4) Formula to convert grams to moles
number of moles = mass in grams / molar mass
5) Number of moles of limiting reactant
a) mass in grams = 379.4 g CaCl₂
b) molar mass CaCl₂ = 110.98 g/mol
c) number of moles CaCl₂ = 379.4 g / 110.98 g/mol = 3.419 moles
6) Theoretical yield of Ca₃(PO4)₂
3 moles CaCl₂ / 1 mole Ca₃(PO4)₂ = 3.419 moles CaCl₂ / x ⇒
x = 3.419 × 1 / 3 = 1.140 moles Ca₃(PO4)₂
7) Convert 1.140 moles Ca₃(PO4)₂
a) molar mass Ca₃(PO4)₂ = 310.1767 g/mol
b) mass in grams = number of moles × molar mass = 1.140 moles × 310.1767 g/mol = 353.6 g ← answer.
Answer:
The oxidation state of N in the KNO3 is +5
Explanation:
Oxidation rules:
1. Oxygen is -2, unless in peroxides.
2. Group 1 metals = +1
3. Group 2 metals = +2
4. If the molecule is neutral, all of the oxidation numbers have to add up to zero.
5. If the molecule is charged, all of the oxidation numbers have to add up to the charge of the molecule.
So, the given formula represents the salt compound formula unit of potassium nitrate: KNO3
The formula unit is uncharged.
From our rules, we know that,
O = -2
And we can find K on the periodic table, in the first group, thus giving it a +1 charge. Now let's put it all together.
K = +1
N = x
O = -2
Let's take into account the number of atoms of each element we have and make an equation since we know everything has to add up to zero since the molecules are neutral.
+1 +x+3 (-2) = 0 (notice we multiplied 3 by -2 because in the formula we have 3 atoms of oxygen with -2 charge each)
x - 5 = 0
x = 5
Therefore, the oxidation number of N in KNO3 is +5.
Energy and the nature of the current
