https://www.physicsforums.com/attachment.php?attachmentid=21003&stc=1&d=1255013927 I need help for number 2(b) A student investigates the evaporation of water. He pours 100 cm3 of water into measuring cylinder A and 100 cm3 of water into measuring cylinder B. Measuring cylinder A is kept at 40 °C and B is kept at 80 °C in the same part of the laboratory. Fig. 2.1 shows the two measuring cylinders after 3 days. The specific latent heat of vaporisation of water is 2300 J / g and the density of water is 1.0 g / cm3. During the three days, the water level in B drops from the 100 cm3 mark to the level shown in Fig. 2.1. Calculate the energy used to evaporate water from B during the three days. Volume = (80-60) = 20 cm3 1 cm3 = 1 g 20 cm3 = 20 g Q= ml Q= 20/1000 x 2300 = 46(Not the right answer) Thanks.