Answer:
Y(OH)₃
Explanation:
Given ions:
Y³⁺ OH⁻
To find a neutral compound that conforms with the formation of the given ions;
We us the exchange of valency approach to solve this problem. The valency will form the combining power of the ions for the combination.
Y³⁺ OH⁻
Combining power 3 1
Exchange of valency 1 3
Now the compound is Y(OH)₃
Let (CH2O)n be molecular formula,
(12+1+1+16)n=90.08
30n=90.08
n=3
molecular formula: (CH2O) 3= C3H6O3
19. D
20. Sorry don’t know but if I had to guess it would be B
21. A because fluorine has a higher electronegativity
22. D
23. B
24. Again don’t really know but I would guess D
25. A
Answer:
-1960 kJ.
Step-by-step explanation:
C₄H₄O₄(s) + 3O₂(g) ⟶ 2H₂O((ℓ)) + 4CO₂(g) + Energy
There are three energy flows in this reaction.
From combustion + warm water + warm calorimeter = 0
q₁ + q₂ + q₃ = 0
nΔH + mCwΔT + CcalΔT = 0
<em>Data:
</em>
Mass of fumaric acid = 1.1070 g
Mass of water = 1.093 × 10³ g
Cw = 4.184 J·°C⁻¹g⁻¹
T₁ = 21.10 °C
T₂ = 24.52 °C
Ccal = 891.1 J·°C⁻¹
Calculations:
(a) <em>q₁
</em>
n = 1.1070 g × (1 mol/116.07 g)
n = 0.009 537 mol
q₁ = 0.009 537ΔH J
(b) <em>q₂
</em>
ΔT = 24.52 – 21.10
ΔT = 3.42°C
q₂ = 1093 × 4.184 × 3.42
q₂ = 15 640 J
(c) <em>q₃
</em>
q₃ = 891.1 × 3.42
q₃ =3048 J
(d) <em>ΔH</em>
0.009 537ΔH + 15 640 + 3048 = 0
0.009 537ΔH + 18 688 = 0
0.009 537ΔH = -18 688
ΔH = -18 688/0.009 537
ΔH = -1 959 413 J/mol
ΔH = -1960 kJ/mol
This is quite different from the actual value of -1334.70 kJ·mol⁻¹
Data:
Arsenic Molar Mass = 74,9216 ≈ 75 u (<span>atomic mass unit)</span>
Solving:
1 mole of arsenic → 75g ------------ 6,02*10²³ molecules
..................................X -------------- 1 molecule
6,02*10²³X = 75