Rate law question in chemistry. Quick Q & A for someone in the know. Very confused.?

Question

A student mixes these volumes of 0.020 M H2SO4, 0,030 M KI and water. Calculate the concentrations of H2SO4 and KI in each solution assuming that all drops are equal in volume, say, 1 mL.

For experiment one, 5 drops of H2SO4 are mixed w/ 7 drops KI and 48 drops of H2O.

For experiment two, 5 drops of H2SO4 are mixed with 10 drops of KI and 45 drops of water.

How do I go about solving this? Please help. Thanks.

Answer 1

What is the volume of one drop ???????????

Answer 2

This is basically a dilution problem. Use M1V1=M2V2, where M's are concentration and V's are volume; 1's are before dilution, and 2's are after. Apply this to each chemical separately.

For experiment 1, the concentration of H2SO4 will be:

M1 = 0.020 M
V1 = 5 drops (because you're using 5 drops of the acid)
M2 = is what you're looking for
V2 = 5+7+48 drops = 60 drops = total volume at the end (all of the drops mixed)
What the volumes of the drops are doesn't matter AT ALL, as long as they are the SAME.

Now solve for M2.

M2 = M1V1/V2
=(0.020 M)*(5 drops)/(60 drops)
=0.00167 M H2SO4

All of the rest are done the same way.