A solution contains 2meq/ml of KCL (molecular weight 74.5). If a 20ml ampule of this solution is diluted to 1 liter, what is the percent strength of the resulting solution?
the volume has increased by a factor of 50, so
the concentration has been reduced to 1/50 of what it was...
To determine the percent strength of the resulting solution, we need to calculate the amount of KCL present in the original 20ml ampule and then determine the concentration of KCL in the resulting 1 liter solution.
Step 1: Calculate the amount of KCL in the original 20ml ampule.
Since the concentration of KCL is given as 2meq/ml, we can calculate the amount of KCL in the original ampule by multiplying the concentration by the volume:
Amount of KCL in the original 20ml ampule = concentration of KCL * volume of solution
= 2 meq/ml * 20 ml
= 40 meq
Step 2: Convert the amount of KCL to grams.
To find the amount of KCL in grams, we need to convert the meq (milliequivalents) to milligrams and then to grams, considering the molecular weight:
Amount of KCL in grams = Amount of KCL in meq * Molecular weight of KCL
= 40 meq * 74.5 g/mole
= 2980 mg
= 2.98 g
Step 3: Calculate the concentration of KCL in the resulting 1 liter solution.
To calculate the concentration, we divide the amount of KCL in grams by the new volume (1 liter):
Concentration of KCL in the resulting solution = Amount of KCL in grams / Volume of resulting solution
= 2.98 g / 1000 ml
= 0.00298 g/ml
Step 4: Calculate the percentage strength of the resulting solution.
To calculate the percentage strength, we multiply the concentration by 100:
Percentage strength = Concentration of KCL in the resulting solution * 100
= 0.00298 g/ml * 100
= 0.298%
Therefore, the resulting solution has a percent strength of 0.298%.