Question

A student measures the mass and volume of a piece of aluminum. The measurements are 25.6 grams and 9.1 cubic centimeters. The student calculates the density of the aluminum. What is the percent error of the student’s calculated density of aluminum?
(1) 1% (3) 3%
(2) 2% (4) 4%

Answer 1

Answer:

D. 4%

Explanation:

The density of aluminum from Reference Table S is 2.70 g/cm3. This is the accepted value. Use the formula for density from Reference Table T and substitute in the values from the question to find the calculated density of Al:

Now use the formula for percent error from Reference Table T, substituting the calculated (measured) and accepted values for the density:

Answer 2

The theoretical density of aluminum is 2.7 g/cm3. The experimental density is 25.6/9.1=2.8 g/cm3. The percent error is (2.8-2.7)/2.7*100%=3.7%≈4%. So the answer is (4) 4%.