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For ai it's atomic number is 13 and it's mass number is 27 how many neutrons does it have

How many grams are in 68.2 molecules of br2?

The combustion of methane, ch4, releases 890.4kj/mol. that is, when one mole of methane is burned,890.4 kj are given off to the surroundings. this meansthat the products have 890.4 kj less than the reactants. thus, ah for the reaction = - 890.4 kj. a negative symbolforah indicates an exothermic reaction. ch (g) + 20 (g)> co2 (g) + 2 h0 (1); ah = - 890.4 kga) how much energy is given off when 2.00 mol of ch, are burned? b) how much energy is released when 22.4g of ch. areburned?