Solve all Mcqs give the right answer quickly

You use the atomic number to find out how many protons and neutrons there are in the atom. you use the atomic mass to find out how many protons and electrons there are in the atom. 

The answer is fossil fuels.

  the volume of  0.220 m k2s    solution  required  to  completely  react with 175 ml  of 0.115m co(no3)2  calculate the moles  of co(no3)2 =  molarity x volume/1000175 x0.115/1000= 0.02  moleswrite  the reacting  equationk2s(aq)  +  co(no3)2  = 2 kno3(aq)  + cos(s)by  use  of mole ratio between k2s to co(no3)2 which  is  1: 1 the moles of k2s is therefore = 175  x0.115/1000= 0.02  molesvolume = moles/molarity=0.02/0.22=0.09  ml  of k2s