What you are given
- Mass you actually weighed (mg): 112
- Molar mass (g/mol): 58.44
- Target concentration (M): 0.1
Formula: V = (m / MW) / c_target
Solutions
How do you calculate the Fixer (rescue a weigh-out)?
Weighed the wrong amount? Get the volume to dissolve it in to hit your target. The relationship used is V = (m / MW) / c_target.
Worked example
Every number below is computed by the calculator, not typed in
The working
- Moles in hand:
mass / MW=1.916 mmol - Dissolve to:
n / c_target=19.165 mL
Dissolve it in 19.165 mL to get 0.1 M.
Try it yourself
Two problems, with the working revealed
Problem 1 The Fixer (rescue a weigh-out)
Work out the result for the Fixer (rescue a weigh-out).
- Mass you actually weighed (mg): 100
- Molar mass (g/mol): 58.44
- Target concentration (M): 0.4
Show the answer and the working
Dissolve it in 4.278 mL to get 0.4 M.
- Moles in hand:
mass / MW=1.711 mmol - Dissolve to:
n / c_target=4.278 mL
Open this in the calculator to change the numbers.
Problem 2 The Fixer (rescue a weigh-out)
Work out the result for the Fixer (rescue a weigh-out).
- Mass you actually weighed (mg): 112
- Molar mass (g/mol): 58.44
- Target concentration (M): 0.15
Show the answer and the working
Dissolve it in 12.777 mL to get 0.15 M.
- Moles in hand:
mass / MW=1.916 mmol - Dissolve to:
n / c_target=12.777 mL
Open this in the calculator to change the numbers.
Do it with your own numbers.
The The Fixer (rescue a weigh-out) calculator is free, shows every step, flags the hazards, and works offline once loaded. No account, no signup.
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