Calculating final concentrations. Your instructor asks you to add the specified quantities of 2M Tris pH 8.0 buffer to 140 ml of distilled water. Calculate the final concentration and dilution factor of each solution.
a)10ml
b)20ml
c)140ml
To calculate the final concentration of the solution, we need to consider the initial concentration of the Tris buffer and the volume of distilled water added.
The initial concentration of the Tris buffer is given as 2M (moles per liter). We can convert this to moles per milliliter by dividing by 1000:
Initial concentration = 2M / 1000 = 0.002 moles per milliliter.
Let's calculate the final concentration and dilution factor for each solution:
a) For 10ml:
The volume of Tris buffer added is 10ml. Therefore, the total volume of the final solution is 10ml (Tris buffer) + 140ml (distilled water) = 150ml.
The final concentration can be calculated using the formula:
Final concentration = (Initial concentration * Initial volume) / Final volume
Final concentration = (0.002 moles/ml * 10 ml) / 150 ml = 0.000133 moles/ml = 0.133M (rounded to three decimal places).
The dilution factor is the ratio of the final volume to the initial volume:
Dilution factor = Final volume / Initial volume
Dilution factor = 150 ml / 10 ml = 15.
b) For 20ml:
The volume of Tris buffer added is 20ml. The total volume of the final solution is 20ml (Tris buffer) + 140ml (distilled water) = 160ml.
Final concentration = (0.002 moles/ml * 20 ml) / 160 ml = 0.00025 moles/ml = 0.25M (rounded to three decimal places).
Dilution factor = 160 ml / 20 ml = 8.
c) For 140ml:
The volume of Tris buffer added is 140ml. The total volume of the final solution is 140ml (Tris buffer) + 140ml (distilled water) = 280ml.
Final concentration = (0.002 moles/ml * 140 ml) / 280 ml = 0.001 moles/ml = 1M.
Dilution factor = 280 ml / 140 ml = 2.