### Alcohol proof general calculation

1. Units and Conversion 1.4) Alcohol proof 1.4.1) Alcohol proof

1.4.1.1) Alcohol proof Normal 1

Total tried:       Correct:       Wrong:

Express 3 gallons of 90 v/v alcohol in terms of the number of proof gallons. Click on the button below to see the answer and explanations

lb equals 5.4 g kg

Alcohol proof is defined as twice the volume percentage of ethanol (measured at 60 °F)
Example 1: At 80 proof (40% alcohol) would be 0.8 proof gallons per gallon of liquid.
Example 2: At 125 proof (87.5% alcohol), a gallon of liquid would be 1.25 proof gallons
Thus, 90 % v/v percent will be 2 × 90 = 180 proof, which is 1.8 proof gallons per gallon of liquid.
This is a volume expansion or concentration dilution type problem. The essential formula is Q_1C_1 = Q_2C_2.
Here,

Q_1 = initial quantity = 3\quadGal.
C_1 = initial concentration = 90 %v/v
Q_2 = final quantity = ?\quad Gal.
C_2 = final concentration = 50%v/v

Therefore, rearranging the formula, we get:
Q_2 = (Q_1×C_1)/(C_2) therefore Q_2 = (3 × 90) /50=5.4 proof gallons, Ans.