Wavelength = 434nm = 434 x 10⁻⁹m
planck's constant = <span>h= 6.626 x 10 ⁻³⁴ J
E =?
by using the formula;
E = hc /</span>λ
value for c is 3 x 10⁸ m/s
E = (6.626 x 10 ⁻³⁴ J)(3 x 10⁸ m/s) / 434 x 10⁻⁹m
E = 1.9878 x 10⁻²⁵ / 434 x 10⁻⁹m
E = 4.58 x 10⁻¹⁹ joules
The answer has to be 22.4L
The reaction between the magnesium, Mg, and the hydrochloric acid, HCl is given in the equation below,
Mg + 2HCl --> H2 + MgCl2
The number of moles of HCl that is needed for the reaction is calculated below.
n = (0.4681 g Mg)(1 mol Mg/24.305 g Mg)(2 mol HCl/1 mol Mg)
n = 0.0385 mols HCl
From the given concentration, we calculate for the required volume.
V = 0.0385 mols HCl/(0.650 mols/L)
V = 0.05926 L or 59.26 mL
<em>Answer: 59.26 mL of HCl</em>
