Answer:
Explanation:
From the question we were given 0.155 moles of HBr, but Br and H are in ratio 1:1, then there are 0.155 moles of Br- ions.
We were also told that the solution contain NaBr, of 25.9 g. Then it must be converted to moles.
molar mass of NaBr =(22.99g + 79.90 )
= 102.89 g per mol.
the moles of NaBr can be calculated as 25.9 / 102.89
=0.252 moles
But Na and Br are in a ratio 1:1 , then there are 0.252 moles of Br-.
Then to get two Br- mol , we will add the first and second mol of Br- together
= 0.155 + 0.252
=0.407 moles.
The given solution has volume of 250 mL, but we know that there are 1000 ml in a liter, then if we convert to L for unit consistency we have
= 250/1000
= 0.25 L
molarity=0.407 moles/0.25 L
= 1.628 M.
Therefore, Br ion molarity is 1.628 M.
Answer:
For the following reaction, 8.00 grams of silicon tetrafluoride are allowed to react with 7.40 grams of water. silicon tetrafluoride (s) + water (l) hydrofluoric acid (aq) + silicon dioxide (s) What is the maximum amount of hydrofluoric acid that can be formed? grams What is the FORMULA for the limiting reagent? H2O What amount of the excess reagent remains after the reaction is complete? grams
Americium is an element named for a country in the Western Hemisphere
Answer:
The correct answer is 40.861 torr.
Explanation:
Based on the given information, the weight of the solute (sucrose) given is 44.6 grams, the weight of the solvent, that is, water given is 62.3 grams, and 42.2 torr is the vapor pressure of pure water.
Now the molecular weight of sucrose is 342 grams per mole, and the molecular weight of water is 18 grams per mole.
The mole fraction of solute will be,
Mole fraction of solute = Weight of solute/Molecular weight of the solute/Weight of the solvent/molecular weight of the solvent + Weight of the solute/Molecular weight of the solute
= 44.6 grams/342 grams per mole/62.3 grams/18 grams per mole + 44.6 grams/342 grams per mole
= 0.1304/3.461 + 0.1304
= 0.0363
Now using relative lowering of vapor pressure,
Vapor pressure of pure water-Vapor pressure of solution/Vapor pressure of pure water = Mole fraction of solute
42.4 torr - PS/42.4 torr = 0.0363
Ps = 42.4 -1.5395
Ps = 40.861 torr
Hence, the vapor pressure of the solution is 40.861.
