Question

1. Express the answer in correct units and with correct number of significant figures:

(2 * 10^3g + 7.191g) / (0.085cm^3 - 0.015cm^3)

2. Calculate the percent error for the following measurements:

a.) The density of alchol (ethanol) is found to be 0.8046 g/mL (true value = 0.7980 g/mL). _____%

b.) The mass of gold in an earring is analyzed to be 0.8453 g (true value = 0.8644 g). ______%

Answer 1

Solution :-

Q1 ) (2 * 10^3g + 7.191g) / (0.085cm^3 - 0.015cm^3) = 3x10⁴

(one significant figure is used in answer because least number of significant figures in the given set up are 1)

a.) The density of alchol (ethanol) is found to be 0.8046 g/mL (true value = 0.7980 g/mL) = 0.8271%

following are the detailed steps

formula to calculate percent error is as follows

% error = (experimental value - accepted value / true value)*100 %

lets put the values in the formual and calculate percent error

% error = (0.8046 g per ml - 0.7980 g per ml / 0.7980 g per ml ) *100 %

              = 0.8271 %

b.) The mass of gold in an earring is analyzed to be 0.8453 g (true value = 0.8644 g). = 2.21 %

following are the detialed steps.

formula to calculate percent error is as follows

% error = (experimental value - accepted value / true value)*100 %

% error = (0.8453 g per ml - 0.8644 g per ml / 0.8644 g per ml )*100%

% error = -2.21 %

but error is never negative so its 2.21 %