Which of the following sources could not be used to obtain the DNA of a person lost in a mass disaster? used and unwashed clothi
2 answers:
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<u>Answer:</u> The molality and molarity of zinc in the solution is 4.07 m and 28.11 M respectively.
<u>Explanation:</u>
Solute is the substance which is present in smaller proportion in a mixture and solvent is the substance which is present in larger proportion in a mixture.
We are given:
(m/m) % of Cu = 79 %
This means that 79 g of copper is present in 100 grams of alloy.
(m/m) % of Zn = 21 %
This means that 21 g of zinc is present in 100 grams of alloy.
As, zinc is present in smaller proportion. So, it is solute and copper is the solvent.
- <u>Calculating molality of zinc:</u>
To calculate molality of the zinc, we use the equation:
where,
= Given mass of solute (Zinc ) = 21 g
= Molar mass of solute (Zinc) = 65.3 g/mol
= Mass of solvent (copper) = 79 g
Putting values in above equation, we get:
- <u>Calculating molarity of zinc:</u>
To calculate volume of a substance, we use the equation:
Density of solution =
(Conversion factors used are: 1 kg = 1000 g & )
Mass of solution = 100 g
Putting values in above equation, we get:
To calculate the molarity of solution, we use the equation:
We are given:
Molar mass of zinc = 65.3 g/mol
Volume of solution = (Conversion factor:
)
Mass of zinc = 21.0 g
Putting values in above equation, we get:
Hence, the molality and molarity of zinc in the solution is 4.07 m and 28.11 M respectively.