Question

A pound of coffee beans yields 50 cups of coffee (4 cups = 1 qt). How many milliliters of coffee can be obtained from 9 g of coffee beans? Round to the appropriate amount of significant figures.

The recommended adult dose of Elixophyllin^®, a drug used to treat asthma, is 6 mg/kg of body mass. Calculate the dose in milligrams for a 170-lb person. Round to the appropriate amount of significant figures.

Answer 1

CONCEPT: In both the problems we have to conver mass from pound to grams and quater (qt) to mL

1 pound = 453.59g, 1 qt = 946.35mL.

(A) CONCEPT: Calculate the no. of cups produced, then convert the cups to quaters (qt), the convert the qt to mL

1 pound or 453.59g of coffee beans produce 50 cups of coffee

1 g will produce = 50 / 453.59 = 0.11 cups

0.11 cups = 0.0275 qt ( SHOWN BELOW)

4 cups = 1qt

1 cup = 1 / 4 = 0.25qt

Therefore 0.11 cups = 0.25 X 0.11 = 0.0275 qt

0.0275 qt = 946.35 x 0.0275 = 26.02mL

Hence one gram of coffee beans producs 26.02mL coffee

9 grams will produce 9 X 26.02 = 234.18mL = 234.2mL

(B) 170 lb = 453.59 X 175 = 79378.25 g

79378.25 g = 79378.25 / 1000 = 79.38 Kg

Recommended dose of Elixophyllin® 6mg/Kg

it means 6mg are required for every kg of body mass

therefore 79.38kg will require 79.38 X 6 = 476.28mg = 476.3mg