Answer:
0.106 mol (3s.f.)
Explanation:
To find the number of moles, divide the mass of glucose (in grams) by its Mr. Glucose has a chemical formula of C6H12O6. To find the Mr, add all the Ar of all the atoms in C6H12O6.
Ar of C= 12, Ar of H= 1, Mr of O= 16
These Ar values can be found on the periodic table.
Mr of glucose= 6(12)+ 12(1) + 6(16)= 180
Moles of glucose
= mass ÷ mr
= 19.1 ÷ 180
= 0.106 mol (3 s.f.)
Answer:
Metals consist of giant structures of atoms arranged in a regular pattern. The electrons from the outer shells of the metal atoms are delocalised , and are free to move through the whole structure. This sharing of delocalised electrons results in strong metallic bonding .
Explanation:
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Answer:
Percent yield = 90.8%
Explanation:
The reaction of Fe with S to produce FeS is:
Fe + S → FeS
<em>Where the moles of Fe added in excess of S are the moles of FeS</em>
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Now, percent yield is defined as 100 times the ratio between actual yield (13.8g of FeS) and theoretical yield (15.2g FeS):
Percent yield = 13.8g / 15.2g * 100
<h3>Percent yield = 90.8%</h3>
Answer:
C) 712 KJ/mol
Explanation:
- ΔH°r = Σ Eb broken - Σ Eb formed
- 1/2Br2(g) + 3/2F2(g) → BrF3(g)
∴ ΔH°r = - 384 KJ/mol
∴ Br2 Eb = 193 KJ/mol
∴ F2 Eb = 154 KJ/mol
⇒ Σ Eb broken = (1/2)(Br-Br) + (3/2)(F-F)
⇒ Σ Eb broken = (1/2)(193 KJ/mol) + (3/2)(154 KJ/mol) = 327.5 KJ/mol
∴ Eb formed: Br-F
⇒ Σ Eb formed (Br-F) = Σ Eb broken - ΔH°r
⇒ Eb (Br-F) = 327.5 KJ/mol - ( - 384 KJ/mol )
⇒ Eb Br-F = 327.5 KJ/mol + 384 KJ/mol = 711.5 KJ/mol ≅ 712 KJ/mol
