How do i do this if carbon has 4 valence electrons and oxygen has six valance electrons how do i do that if they only need eight valance electrons

Ineed this asap part i: scientific method what is the difference between science and pseudoscience? what is the scientific method?

What amount of heat is exchanged when 106.2 grams of substance y goes from a liquid at 35 degrees celsius to a solid at the same temperature? melting point of substance y = 35 degrees c; δhvaporization = 3.67 j/mol; δhfusion = 3.30 j/mol. mwsubstance y = 28.22 g/mol. −12.4 j −3.51 x 102 j 1.24 x 101 j 351 j

When the mercury level in a barometer decreases that atmospheric pressure has