A 1.0-mL volume of 0.010 M H2SO3 is added to a mixture of 12 drops of 0.010 M HIO3, 8 drops of deionized water, and 1 drop of starch solution. a color change occured after 40 seconds.
assuming 25 drops per mL for all solutions, determine the initial molar concentration of HIO3 after the mixing but before any reaction occurs (at time 0)
To determine the initial molar concentration of HIO3 after mixing but before any reaction occurs, we need to calculate the total volume of the mixture and the number of moles of HIO3 present.
Let's start by calculating the total volume of the mixture:
12 drops of HIO3 + 8 drops of water + 1 drop of starch solution = 21 drops
Using the conversion rate of 25 drops per mL, we can calculate the total volume in mL:
21 drops / 25 drops/mL = 0.84 mL
Now we need to determine the number of moles of HIO3 in the mixture. We can use the given molar concentration of HIO3 and the total volume of the mixture:
Molar concentration of HIO3 = 0.010 M
Volume of mixture = 0.84 mL
Now we can calculate the number of moles of HIO3:
Number of moles of HIO3 = Molar concentration x Volume
= 0.010 M x 0.84 mL
To ensure the units are consistent, we convert mL to L:
0.84 mL x (1 L / 1000 mL) = 0.00084 L
Number of moles of HIO3 = 0.010 M x 0.00084 L
Now we can calculate:
Number of moles of HIO3 = 0.010 x 0.00084
Therefore, the initial number of moles of HIO3 in the mixture at time 0 is equal to 0.000084 moles.
To determine the initial molar concentration of HIO3, we divide the number of moles by the total volume of the mixture:
Initial molar concentration of HIO3 = Number of moles / Volume of mixture
Initial molar concentration of HIO3 = 0.000084 moles / 0.84 mL
Again, we convert mL to L:
0.84 mL x (1 L / 1000 mL) = 0.00084 L
Initial molar concentration of HIO3 = 0.000084 moles / 0.00084 L
Finally, we can calculate:
Initial molar concentration of HIO3 = 0.000084 moles / 0.00084 L
Therefore, the initial molar concentration of HIO3 after the mixing but before any reaction occurs (at time 0) is equal to 0.100 M (rounded to three significant figures).