Answer;
= 18.24
Explanation;
The ratio of N and O in the formula NO2 IS 1:2
Mass of nitrogen gas is 0.500 g
Moles of nitrogen will be;
= 0.500/16 = 0.03125 moles
Therefore;
The moles of Oxygen from the ratio will be;
= 0.03125 × 2 = 0.0625 moles
But; 0.0625 moles is equal to 1.140 g of Oxygen
The atomic number (mass in 1 mole) will be;
= 1.140 /0.0625
= 18.24
Thus the atomic number of Oxygen from the data is 18.24
Answer
a) A solution with a hydronium molarity of 0.00045 is acidic. True
Doing the calculus of pH
![pH= -Log [H^{+}] = -Log (0.00045)](https://tex.z-dn.net/?f=pH%3D%20-Log%20%5BH%5E%7B%2B%7D%5D%20%3D%20-Log%20%280.00045%29)
b) pH is a way to express the hydronium concentration over a wide range. True
pH means –Log[H+] and this value is used to express a wide range of hydronium concentration sometimes obtaining pH minor than zero.
c) Percent K and Fe are determined by doing ion exchange then a pH titration. False
Usually, Fe is determined by redox titration with potassium permanganate due to it’s more accurate. On the other hand, K is determined usually by volumetric process which includes precipitation like potassium picrate precipitate
d) About 0.2M HCl is the reagent used for the pH titrations. False.
In order to do pH titration, it is possible to use a wide range of HCl concentrations and other acids as reagent if the analyte is a basic compound. Otherwise, if the analyte is an acid compound you should use a basic compound as reagent.
e) A Lewis base is specie that can donate a proton to an acid. False
A Lewis base is an electron pair donor.
O2 and O3 are allotropes of Oxygen, therefore they have (4) different chemical and physical properties.
The formula to be used for this problem is as follows:
E = hc/λ, where h is the Planck's constant, c is the speed of light and λ is the wavelength. Also 1 aJ = 10⁻¹⁸ J
0.696×10⁻¹⁸ = (6.62607004×10⁻³⁴ m²·kg/s)(3×10⁸ m/s)/λ
Solving for λ,
λ = 2.656×10⁻⁷ m or <em>0.022656 nm</em>