The equation X + Y -> XY is the general equation for what type of reaction

Asa choose the correct set of reaction coefficients to properly balance the following chemical equation according to the law of conservation of mass: __s8 + __o2 ==> __so2 1, 1, 8 1, 8, 1 1, 8, 8 8, 1, 1

What is the number of moles of chemical units represented by 9.03x10^24? and how do i show work? (dumb it down )

What is the percentage of hydrogen in c2h4