When oxygen reacts with hydrogen, it has the capacity to release 29 kilojoules of energy. Inside a fuel cell, oxygen reacts with hydrogen to produce 23 kilojoules of useful energy. The rest of the energy is lost as heat. What’s the efficiency percentage of the fuel cell? : 25 points

Why does the sun appear to be the brightest star in the sky? a- its apparent brightness is much greater than other stars. b- it burns more gas, making it brighter than any other star. c- it is the largest star in the galaxy, so it is the brightest star. d- its relative distance to earth is closer than the other stars.

In apex! a liquid heated beyond a certain temperature becomes

How many grams of oxygen gas are contained in a 15 l sample at 1.02 atm and 28°c? show your work.