Question #59098
1 Answer
Explanation:
A good approach to have here is to take the dilutions one at a time.
The dilution factors of each dilution step will determine the overall dilution factor of the sample.
So, a dilution factor is simply the ratio between the initial volume of the sample and the final volume of the solution afterthe dilution takes place.
#"D.F." = V_"initial"/V_"final"#
So, you starting sample has a volume of
So, what is the final volume for this dilution?
#V_"final 1" = V_"initial 1" + V_"saline 1"#
#V_"final 1" = 150mu"L" + 300mu"L" = 450mu"L"#
The dilution factor for this first step will thus be
#"D.F"_1 = (150color(red)(cancel(color(black)(mu"L"))))/(450color(red)(cancel(color(black)(mu"L")))) = 1/3#
Now you take a
The initial volume for this second dilution is
#V_"final 2" = V_"initial 2" + V_"saline 2"#
#V_"final 2" = 20mu"L" + 180mu"L" = 200mu"L"#
The dilution factor for this second step is
#"D.F"_2 = (20color(red)(cancel(color(black)(mu"L"))))/(200color(red)(cancel(color(black)(mu"L")))) = 1/10#
The total dilution factor will simply be the product of the two dilution factors that characterized the two dilution steps
#"D.F"_"total" = "D.F"_1 xx "D.F"_2#
#"D.F"_"total" = 1/3 xx 1/10 = color(green)(1/30)#