As a bicycle pump inflates a tyre, it pressure rises from 30 kPa to 40 kPa at constant temperature of 30 °C. By assuming the air acts as an ideal gas, calculate the work done per mol of the air. 
A. -80.35 J 
B. 80.35 J 
C. -811.93 J 
D. 811.93 J 
(please show calculation)
 can use this formula W=nRT ln(p1/p2)