When water reacts with potassium metal the hydrogen produced ignites explosively on the surface of water .What cause the ignition

The blackbody curve for a star name zeta is shown below. what is the peak wavelength for this star ?

Ammonium perchlorate nh4clo4 is the solid rocket fuel used by the u.s. space shuttle. it reacts with itself to produce nitrogen gas n2 , chlorine gas cl2 , oxygen gas o2 , water h2o , and a great deal of energy. what mass of nitrogen gas is produced by the reaction of 2.1g of ammonium perchlorate?

Structure of the atoms: discovery of the nucleus in 1909i need answering all of these questions