3) The specific heat of element X is 0.50/g K. The compound of X with oxygen has

Question

3) The specific heat of element X is 0.50/g K. The compound of X with oxygen has the composition by mass of 63.19 % X and 36.81 % o. Using the Law of Dulong and Petit (at.wt.)(sp.ht) - 6.3, determine the approximate atomic weight of X? What is the formula of the X oxide? What is the exact atomic weight of X? Approximate atomic weight is 52. The formula of the oxide is X02. The exact atomic weight 54.9 4. The reaction of sulfuric acid with sodium carbonate in aqueous solution represented by the following equation. H2S04(aq) + Na2CO3Caq)-Na2SO Caa) +H20(l)+ CO2(g) Assume that the reaction is carried out at under standard thermodynamic conditions. Compute the amount of pressure volume work that is done by the system on the surroundings when one mole of sulfuric acid reacts with one mole of sodium carbonate-24.5 L atm

Explanation / Answer

3. Specific heat of X = 0.5 J/ g K = 500

According to law of Dulong and Petit,

Atomic weight * specific heat = 3R = 3 * 8.314 = 24.942

The statement mentioned in the problem seems to not be following this rule.

We use the value 24.942 instead of 6.3 which gives us an answer close to the answer mentioned.

Therefore approx Atomic weight = 24.942 / 0.5 = 49.884

In the oxide of X, percentage of X is 63.19% and that of O is 36.81%

We try various possible compositions like XO, XO2, XO3, X2O, X2O3 etc

In case of XO2, weight of X= 49.884 and O= 15.999*2 = 31.998

Total = 49.884 + 31.998 = 81.882

%X = 49.884*100/81.882 = 60.922

%O = 39.078

Thus this is the closest posible configuration- XO2

For exact atomic weight of X to satisfy all conditions, let us assume it as w

Thus weight of XO2 = w + 31.998

Now, 36.18 = 31.998 * 100 / (w + 31.998)

Thus w = (3199.8 - 1157.687) / 36.18 = 56.44314

These values are not the same as mentioned in the question but the calculations are sound.

Related Questions

Navigate

• Browse (All)
• Browse 3
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.