I am having trouble with this question: The temperature of the espresso coffee (mostly water) can be increased by blowing 100 C steam into it. How much steam (in grams) is needed to heat up a 20 cm^3 cup of espresso from 50 C to 80 C? What is the volume of this quantity of steam assuming that the steam is an ideal gas? So far I have started like so: Since the 20 cm^3 conversion to grams with water is just 1:1 I just said 20 g of water for starting. And approached it like so: (20g)(1 g/cal)(80 C – 50 C)= -ms(-540 cal/g) + (1 cal/g)(80 C – 100 C) and got ms to be roughly 1.11 g of steam.