The world’s largest jelly, which had a mass of about 4.00 × 104 kg, was made in Australia in 1981.
a. How much energy must be transferred by heat from the jelly in order for its temperature to decrease 20.0°C? Assume that the specific heat capacity of the jelly equals that of water.
b. Suppose all this energy is transferred by heat to a sample of gas. At the same time, the gas does 1.64 × 109J of work on its surroundings. What is the net change in the internal energy of the gas?

Uranium has two naturally occurring isotopes. 238u has a natural abundance of 99.3% and 235u has an abundance of 0.7%. it is the rarer 235u that is needed for nuclear reactors. the isotopes are separated by forming uranium hexafluoride uf6, which is a gas, then allowing it to diffuse through a series of porous membranes. 235uf6 has a slightly larger rms speed than 238uf6 and diffuses slightly faster. many repetitions of this procedure gradually separate the two isotopes. what is the ratio of the rms speed of 235uf6 to that of 238uf6? express your answer to five significant figures.