How many molecules of HCI would react with 1 mol of MgO?

C.

Explanation:

MoleculesHcl = (1 molMgO/1)(2molHCL/1molMGO)(6.02x10^23/1molHCL) = 1.204x10^24

so here we go

atomic mass

239 + 1 = y + 134 + 3 combine like terms

240 = y + 137             subtract 137 from both terms

240 - 137 = y

103 = y

atomic number

94 = z +54 + 0

94 = z + 54               subtract 54 from both sides.

40 = z

answer