Answer
0.01 g, 0.005 g, 0.00225, 0.23%
Work Step by Step
For the measurement 2.22 g, we have
The precision is 0.01 g
The greatest possible error is one-half the precision
$0.5\cdot 0.01\ g=0.005 \ g$
The relative error is
$relative~error=\dfrac{greatest~possible~error}{measurement}$
$\frac{0.005\ g}{2.22\ g}=0.00225$
The percent of error is $0.23\%$
