So for D you have to find energy right
from c you get wavelength Lambda
so on D use this
E = Hc / lambda
c is given 1.5 x 10 ^20
h = 6.624 x 10^-34
and then you get answer for energy
Is this a real question? It’s B
Answer:
120g
Explanation:
We'll begin by writing the balanced equation for the reaction. This is given below:
Sn + 2HF —> SnF2 + H2
Next, we shall determine the number of mole of HF needed to react with 3 moles of Sn.
From the balanced equation above, 1 mole of Sn reacted with 2 moles of HF.
Therefore, 3 moles of Sn will react with = 3 x 2 = 6 moles of HF.
Finally, we shall convert 6moles of HF to grams
This is illustrated below:
Number of mole of HF = 6moles
Molar Mass of HF = 1 + 19 = 20g/mol
Mass of HF =..?
Mass = number of mole x molar Mass
Mass of HF = 6 x 20
Mass of HF = 120g
Therefore, 120g of HF is needed to react with 3 moles of Sn
We are given with a compound, Zinc (Zn) having a 1.7 x 10
^23 atoms. We are tasked to solve for it's corresponding mass in g. We need to
find first the molecular weight of Zinc, that is
Zn= 65.38 g/mol
Not that 1 mol=6.022x10^{23} atoms, hence,
1.7 x 10 ^23 atoms x 1 mol/6.022x10^{23} atoms x65.38
g/ 1mol
=18.456 g of Zn
Therefore, the mass of Zinc 18.456 g
