Pb(OH)2
This is the formula
We are given with the mass of Arsine (
The mass of arsine is 15g
there is a relation between moles, mass and molar mass of any compound which is

The molar mass of Arsine = atomic mass of As + 3X atomic mass of H
the molar mass of Arsine = 74.92 + 3X 1 = 77.92 g/mol
Let us calculate the moles as

Answer: The percent of yield is 50.03%.
Explanation:
First, we need to balance the equation:
⇒ 
We need to remember that the chemical equations are written in moles, so we have to convert the amounts in grams to moles, using the molecular weight of every compound: Al2O3 (101.96 g/mol), Al (29.98 g/mol) and O2 (31.99 g/mol).
In consequence, the amounts in moles of every compound will be:



Now, we have to find out which is the limit reagent or in other words, which of the reagents will be consumed first, taking into account the stoichiometric ratio of the balanced equation:


As you can see, the maximum amount (theoretically) of Al2O3 that can be produced is 0.1665 mol.
Finally, we have to use the yield formula to calculate the percent yield of the reaction:

Therefore, the percent of yield is 50.03%.
Answer: 46. E 47. D 48. C 49. A
50. A 51. D 52. B 53. B 54. C
Explanation: solution attached.
<span>Colligative properties are dependent upon the number of molecules or ions present in solution. Therefore, 1 mole of Na2SO4 will produce 3 moles of ions and so it will have 3 times as much of an effect as 1 mole of sugar, which is not an electrolyte and can't dissociate to an appreciable extent.</span>