Answer:
Pb: 22.4 at%
Sn: 77.6 at%
Explanation:
It is possible to find at% of Pb and Sn converting mass in moles using molar mass assuming a basis of 100g, thus:
Pb: 33.5g × (1mol / 207.2g) = <em>0.1617mol</em>
Sn: 66.5g × (1mol / 118.7g) = <em>0.5602mol</em>
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Total moles: 0.1617mol + 0.5602mol = 0.7219mol
Composition in at%:
Pb: 0.1617mol / 0.7219mol × 100 = <em>22.4 at%</em>
Sn: 0.5602mol / 0.7219mol × 100 = <em>77.6 at%</em>
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I hope it helps!
<h3><u>Answer</u>;</h3>
= 226 Liters of oxygen
<h3><u>Explanation</u>;</h3>
We use the equation;
LiClO4 (s) → 2O2 (g) + LiCl, to get the moles of oxygen;
Moles of LiClO4;
(500 g LiClO4) / (106.3916 g LiClO4/mol)
= 4.6996 moles
Moles of oxygen;
But, for every 1 mol LiClO4, two moles of O2 are produced;
= 9.3992 moles of Oxygen
V = nRT / P
= (9.3992 mol) x (8.3144621 L kPa/K mol) x (21 + 273) K / (101.5 kPa)
= 226 L of oxygen
Answer:
Explanation:
<u>1) Convert the mass of water into number of moles</u>
- Molar mass of water: 18.015 g/mol
- Number of moles, n = mass in grams / molar mass
n = 255 g / 18.015 g/mol = 14.15 mol
<u>2) Use the formula E = n × ΔH vap</u>
This is, you have to multiply the molar ΔH vaporization by the number of moles to find the total energy to boil the given amount of water.
- E = 14.15 mol × 40,650 J/mol = 575,395.5 J
<u>3) Round to the correct number of significant figures.</u>
The mass of water is the measurement with the least number of significant figures (3), so you must report the answer with 3 significant figures,
He is the only one that includes only mollecules
I Gallon = 3.785 L 1 Mg = 1 mg gallon 3.785L. 3. The recommended adult dose of Elixophyllin®, a drug used to treat asthma, is 6.00 mg/kg of body mass. Calculate the dose in milligrams for a 112 lb person. (o oo Kg | K9 6.oong 112 15 = 3 04.7 - 3 2.20515 2.20516 my k.
Hope this answer will help you.
