Brass is an alloy that is approximately 67% Cu and 33% Zn, by mass. How many grams of Cu are in a brass door knocker weighing 2.2 pounds? (1 lb = 453.6 g)
.67 * 2.2 lb * 453.6g/lb = ____ g
To find the number of grams of Cu in a brass door knocker, we can use the percentage composition by mass of Cu in brass.
Given that brass is approximately 67% Cu and 33% Zn, we can assume that the 2.2 pounds weight of the door knocker is made up of 67% Cu and 33% Zn.
First, let's convert the weight of the door knocker from pounds to grams:
2.2 pounds = 2.2 * 453.6 grams = 997.92 grams (rounded to two decimal places)
Now, we can find the number of grams of Cu in the door knocker by multiplying the total weight by the percentage composition of Cu:
grams of Cu = 997.92 grams * 67% = 997.92 grams * (67/100) = 668.78 grams (rounded to two decimal places)
Therefore, there are approximately 668.78 grams of Cu in the brass door knocker weighing 2.2 pounds.