Mass percent, dilution and yield: spreadsheet examples
Work through mass percent, serial dilution factors, and purity-adjusted reaction yield, with explicit units and checks that keep these calculations distinct.
Mass percent compares solute mass with total solution mass. A dilution factor compares final volume with transferred stock volume. Percent yield compares recovered product with theoretical product. Keep those denominators and units explicit; the three calculations are not interchangeable concentration measures.
How do you calculate mass percent from solute and solvent?
For 5 grams of solute and 95 grams of solvent, total solution mass is 100 grams. Mass fraction is 5/100, or 0.05. Displayed as a percentage, that is 5 percent by mass. IUPAC defines mass fraction as constituent mass divided by total mixture mass.
With solute in B11 and solvent in C11, use =B11+C11 for total mass and =IF(D11<=0,"",B11/D11) for mass fraction. Apply a percentage number format to the fraction rather than multiplying it by 100 and applying percentage formatting again.
The mass percent worksheet uses mass inputs only. It does not assume that 100 grams of solution occupies 100 milliliters. Converting to a mass-per-volume concentration requires appropriate volume or density information.
How do you calculate a serial dilution factor?
Transferring 1 milliliter of stock and adding 9 milliliters of diluent gives 10 milliliters of final volume under the additive-volume assumption. Dilution factor is 10/1, or 10. A stock concentration of 100 in a chosen unit becomes 10 in the same unit.
A second tenfold step reduces 10 to 1. A third step transferring 2 milliliters into 8 milliliters of diluent has a factor of 5, reducing 1 to 0.2. The overall factor is 10*10*5, or 500.
Each row must use the concentration actually entering that step. If you change an earlier step in an independent scenario table, update the next starting concentration or link it explicitly to the prior result. The Notes in the dilution workbook state this dependency so independently entered rows are not mistaken for a linked serial model.
How does purity change a reaction yield calculation?
Suppose theoretical product mass is 10 grams, measured recovered mass is 9 grams, and entered purity is 98 percent. Pure product mass is 9*0.98, or 8.82 grams. Purity-adjusted yield is 8.82/10, or 88.2 percent.
Without the purity adjustment, the apparent mass yield would be 90 percent. Keep both the measured mass and purity as inputs so the adjustment can be traced. The reaction yield worksheet leaves yields above 100 percent visible for investigation rather than capping them.
Which chemistry worksheet inputs require separate evidence?
Theoretical yield needs a justified stoichiometric basis. Purity needs an appropriate analytical basis. Dilutions need compatible concentration and volume units, and preparation may require non-additive volume treatment.
These examples explain arithmetic. They do not specify safe preparation conditions, chemical compatibility, or handling procedures. Use the actual material documentation and laboratory procedure before preparing a solution or carrying out a reaction.