Answer:
Because no two elements have the same set of energy levels, different elements emit different colors of light. Energy is released when electrons move from higher energy levels to lower ones (visible light).
Explanation:
CH4+(x)O2=CO2 +(Y)H2O
C=1 +H=4 +O=? = C=1 +O=2+? +H=?
H=4>>Y=2
C=1 +H=4 +O=? = C=1 +O=(2+2) +H=4
C=1 +H=4 +O=4 = C=1 +O=4 +H=4
O=4>>X=2
CH4+(2)O2 =CO2 +(2)H2O
H2SO4 ---> 2H^+ + SO4^2-
Hence n H+ = 9 mols
Mass of H = nM = (9*1) = 9g
Alternately
mass of H2SO4= nM= 4.5*98= 441
Mass of H= mass h2so4 * molar mass of H/molar mass of h2so4
Mass of H= 441 * 2/98 = 9g
There is different types of salt.
1)table salt
2)lime salt
Both aluminum and chlorine have known charges, which are +3 and -1 respectively. To make them cancel each other out in charge, you would need 3 chlorine and for one aluminum, therefore

would be correct