The moles of potassium nitrate present in the 50 ml of 0.2M solution has been 4 moles.
Molarity can be defined as the moles of solute in a litre of solution. The solution of potassium nitrate has been prepared to be of Molarity 0.2 M. The moles of solute present in the solution can be calculated as:
Molarity = moles volume (L)
The given volume = 50 ml
1000 ml = 1 L
50 ml = 0.05 L
Molarity of the solution = 0.2 M
The moles of solute:
0.2 = moles 0.05
Moles of Potassium nitrate = 4
The moles of potassium nitrate present in the 50 ml of 0.2M solution has been 4 moles.
For more information about the moles of solute, refer to the link:
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To solve this we use the equation,
M1V1 = M2V2
where M1 is the concentration of the stock solution, V1 is the volume of the stock solution, M2 is the concentration of the new solution and V2 is its volume.
.675 M x V1 = .25 M x 1.3 L
V1 = 0.48 L or 480 mL
If a chemist wants to make 1.3 L of 0.25 M solution of KOH by diluting a stock solution of 0.675 M KOH, the chemist would need to use 480 mL of the stock solution.
b. radiometric dating.
c. dendrochronology.
d. radioactive dating.