Answer :
1-61.11 ml of the 18 M solution is required to prepare 550 ml of a 2.0 M solution.
2-0.117 liters or 117 ml of the 1.5 M solution is required to prepare 25 ml of a 7.0 M solution.
To calculate the volume of concentrated 18 M solution required to prepare 550 ml of a 2.0 M solution, we can use the formula:
M1V1 = M2V2
where:
M1 = 18 M (concentration of concentrated solution)
V1 = volume of concentrated solution to be added (unknown)
M2 = 2.0 M (final concentration required)
V2 = 550 ml (final volume required)
Rearranging the formula to solve for V1:
V1 = (M2 x V2) / M1
Substituting the values given:
V1 = (2.0 M x 550 ml) / 18 M
V1 = 61.11 ml
To calculate the volume of concentrated 1.5 M solution required to prepare 25 ml of a 7.0 M solution, we can again use the formula:
M1V1 = M2V2
where:
M1 = 1.5 M (concentration of concentrated solution)
V1 = volume of concentrated solution to be added (unknown)
M2 = 7.0 M (final concentration required)
V2 = 25 ml (final volume required)
Converting the final volume required to liters:
V2 = 25 ml = 0.025 L
Rearranging the formula to solve for V1:
V1 = (M2 x V2) / M1
Substituting the values given:
V1 = (7.0 M x 0.025 L) / 1.5 M
V1 = 0.117 L
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