Answer:
f = 5.25 x 10³⁸ s⁻¹
Explanation:
Energy = 348KJ = 348,000 J
Frequency = ?
Energy and frequency are related by the equation below;
E = hf
where h = Planck's constant = (6.626 x 10-34 J · s),
Upon making f subject of formular;
f = E / h
substituting the values, we have;
f = 348,000 / 6.626 x 10-34
f = 52,520 x 10 ³⁴ s⁻¹
f = 5.25 x 10³⁸ s⁻¹
Answer: The concentration of excess ![[OH^-]](https://tex.z-dn.net/?f=%5BOH%5E-%5D)
in solution is 0.017 M.
Explanation:
1. 
moles of 
1 mole of 
give = 1 mole of 
Thus 0.019 moles of give = 0.019 mole of
2. moles of 
According to stoichiometry:
1 mole of 
gives = 2 moles of 
Thus 0.012 moles of give = 
moles of
As 1 mole of neutralize 1 mole of
0.019 mole of will neutralize 0.019 mole of
Thus (0.024-0.019)= 0.005 moles of will be left.
![[OH^-]=\frac{\text {moles left}}{\text {Total volume in L}}=\frac{0.005}{0.3L}=0.017M](https://tex.z-dn.net/?f=%5BOH%5E-%5D%3D%5Cfrac%7B%5Ctext%20%7Bmoles%20left%7D%7D%7B%5Ctext%20%7BTotal%20volume%20in%20L%7D%7D%3D%5Cfrac%7B0.005%7D%7B0.3L%7D%3D0.017M)
Thus molarity of in solution is 0.017 M.
First, we write the half equations for the reduction of the chemical species present:
Cu⁺² + 2e → Cu; E° = 0.34 V
Ni⁺² + 2e → Ni; E° = - 0.23 V
In order to determine the potential of the cell, we find the difference between the two values. For this:
E(cell) = 0.34 - (-0.23)
E(cell) = 0.57 V
The second option is correct. (The difference in values is due to different values in literature, and it is negligible)
The moles of chromium (iii) nitrate produced is calculated as follows
write the equation for reaction
3 Pb(NO3)2 + 2 Cr = 2 Cr(NO3)3 + 3 Pb
by use of mole ratio between Pb(NO3)2 to Cr(NO3)3 which is 3 : 2 the moles of Cr(NO3)3 is therefore
= 0.85 x2 /3 = 0.57 moles
Density of a substance is defined as the mass of the substance divided by the volume.
Density of the substance= 0.242 g cm⁻³
volume of the substance= 2.50 in³
As, 1 in³= 16.39 cm³
So, 2.50 in³= 16.39× 2.50 cm³=40.97 cm³
As ,
Mass=volume ×Density
Mass=40.97 × 0.242
Mass=9.916 g.
