Answer:

Explanation:
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In this case, considering the given chemical reaction:

Thus, by applying the law of rate proportions, we can write:

Whereas the stoichiometric coefficients of reactants are negative due their disappearance and that of the product is positive due to its appearance. In such a way, when we relate the rate of disappearance of hydrogen gas to the rate of formation of hydrogen iodide, we obtain:

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Speed of light = 3x10^8 m/s
Mass of electron = 9.11x10^-31 kg
70% of 3x10^8 = 2.1x10^8 m/s
206.8*9.11x10^-31 = 1.88x10^-28 kg
Equation for wavelength is: wavelength= plancks constant / (mass*velocity)
Plancks constant = 6.62x10^-34 m^2 kg/s
Plug all of these in and you get: 6.62x10^-34 / (1.88x10^-28/2.1x10^8) = 739.47
Your answer is 739.47 m
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