They start with the numbers u need to know in order to slove the problem and there has to be a story behind it
Answer:
2NO(g) + O2(g) --> 2NO2(g)
now 400 ml of NO × 2 mol of NO2/2 mol of NO
= 400 ml of NO2
now 500 ml of O2 × 2 mol of NO2/1 mol of O2
= 1000 ml of NO2
now 400 ml of NO2 × 1 mol of O2/2 mol of NO
= 200 ml
subtract that from 500 ml of total i.e. 500-200 =300 ml
The total volume of the reaction mixture is 1000 ml -300ml = 700 ml
The gas particles squeeze closer together
The chain reaction is easy to stop. Just add a neuron absorbing material. The Control Rods in rectors can do that You just SCRAM (put the rods all the way in) or add something like Boron and the chain reaction stops.
<span>The problem is the radioactive waste. Those isotopes break down and release heat spontaneously, no neutrons required. The only known way to stop or slow radioactive decay down is to slow time down by moving at relativistic speed or near orbit to a black hole.</span>