Final answer:
The number that represents a coefficient in the given chemical reaction product side '7T1:(50.)3' is 7, as it is the number immediately preceding the chemical formula.
Step-by-step explanation:
In chemical reactions, the coefficients are the numbers that appear in front of the chemical formulas. They indicate the relative numbers of molecules of reactants and products involved in the reaction. For example, in the equation 2H2 + O2 → 2H2O, the number 2 in front of H2 and H2O are coefficients. Given the product side of the chemical reaction 7T1:(50.)3, the number that represents a coefficient is 7, because it is the number placed immediately to the left of the molecular formula indicating how many units of the substance are involved.