A flask containing helium gas is connected to an open-ended mercury manometer. The open end is exposed to the atmosphere, where
1 answer:
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Number of moles is defined as the ratio of given mass in g to the molar mass.
The mathematical formula is:
Number of moles = (1)
Number of zinc atoms is equal to , by Avogadro number, number of moles can be calculated.
As, 1 mol= atoms, hence,
= 0.2822 mol
Now, from formula (1), calculate mass in g (molar mass of zinc = 65.4 g/mol)
0.2822 mol =
mass in g =
= 18.45588 g
Thus, by rounding off the above number, it will come near about 19 g approximately.
Hence, option (C) is the correct answer.
Answer:
The mass percentage of the solution is 10.46%.
The molality of the solution is 2.5403 mol/kg.
Explanation:
A bottle of wine contains 12.9% ethanol by volume.
This means that in 100 mL of solution 12.9 L of alcohol is present.
Volume of alcohol = v = 12.9 L
Mass of the ethanol = m
Density of the ethanol ,d=
Mass of water = M
Volume of water ,V= 100 mL - 12.9 mL = 87.1 mL
Density of water = D=1.00 g/mL
Mass percent
Molality :
M = 87.1 g = 0.0871 kg (1 kg =1000 g)