You know from the chemical formula that 1 mole of Cu3(PO4)2 contains 2 moles of P so you can work out how many moles of P are in 8.1 moles of Cu3(PO4)2.
<span>As for anything, 1 mole of X contains 6.022 * 10^23 of X. Multiply moles of X by Avogadro's number.</span>
Answer:
ΔH = -20kJ
Explanation:
The enthalpy of formation of a compound is defined as the change of enthalpy during the formation of 1 mole of the substance from its constituent elements. For H₂S(g) the reaction that describes this process is:
H₂(g) + S(g) → H₂S(g)
Using Hess's law, it is possible to sum the enthalpies of several reactions to obtain the change in enthalpy of a particular reaction thus:
<em>(1) </em>H₂S(g) + ³/₂O₂(g) → SO₂(g) + H₂O(g) ΔH = -519 kJ
<em>(2) </em>H₂(g) + ¹/₂O₂(g) → H₂O(g) ΔH = -242 kJ
<em>(3) </em>S(g) + O₂(g) → SO₂(g) ΔH = -297 kJ
The sum of -(1) + (2) + (3) gives:
<em>-(1) </em>SO₂(g) + H₂O(g) → H₂S(g) + ³/₂O₂(g) ΔH = +519 kJ
<em>(2) </em>H₂(g) + ¹/₂O₂(g) → H₂O(g) ΔH = -242 kJ
<em>(3) </em>S(g) + O₂(g) → SO₂(g) ΔH = -297 kJ
<em>-(1) + (2) + (3): </em><em>H₂(g) + S(g) → H₂S(g) </em>
<em>ΔH =</em> +519kJ - 242kJ - 297kJ = <em>-20 kJ</em>
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I hope it helps!
Answer:
+6
Explanation:
We are given;
We are required to determine the oxidation number of S in the compound.
We need to know that;
- The total oxidation number of this compound is Zero
- Oxidation number of Ba metal is +2
- Oxidation number of Oxygen atom is -2
- There is 1 atom of Ba, 1 atom of S and 4 atoms of O in the compound.
Therefore; assuming oxidation number of S is x
Then, (1× 2) + (1 × x) + ( 4 ×(-2)) = 0
2 + x - 8 = 0
x = 6 or +6
Thus oxidation number of Sulfur in BaSO₄ is +6.
Atomic weight is Ar of the atom (what you see on the periodic table)
atomic weight<span> is relative </span>atomic mass, so yeah same thing
