What is the number of photons of light with a wavelength of 4000 pm that provide 1 J of energy?
Energy (E) of a photon = hc/λ
Where,λ = wavelength of light = 4000 pm = 4000 ×10–12 m = 4x 10-9 m
c = velocity of light in vacuum = 3 × 108 m/s
h = Planck’s constant = 6.626 × 10–34 Js
thefore the energy of photon (E)
= 6.626 × 10–34 Js X 3 × 108 m/s / 4x 10-9 m = 4.965 x 10-16 J
Now 4.965 x 10-16 J is the energy of = 1 photon
Therefore 1 J will be the energy of = 1/4.965 x 10-16 J = 2.014 x 1015 photons
The mass of an electron is 9.1 × 10–31 kg. If its K.E. is 3.0 × 10–25 J, calculate its wavelength.
Calculate the amount of carbon dioxide that could be produced when
(i) 1 mole of carbon is burnt in air.
(ii) 1 mole of carbon is burnt in 16 g of dioxygen.
(iii) 2 moles of carbon are burnt in 16 g of dioxygen.
Calculate the wavelength of an electron moving with a velocity of 2.05 × 107 ms–1.
Balance the following redox reactions by ion – electron method :
(a) MnO4 – (aq) + I – (aq) → MnO2 (s) + I2(s) (in basic medium)
(b) MnO4 – (aq) + SO2 (g) → Mn2+ (aq) + HSO4– (aq) (in acidic solution)
(c) H2O2 (aq) + Fe 2+ (aq) → Fe3+ (aq) + H2O (l) (in acidic solution)
(d) Cr2O7 2– + SO2(g) → Cr3+ (aq) + SO42– (aq) (in acidic solution)
In a process, 701 J of heat is absorbed by a system and 394 J ofwork is done by the system. What is the change in internal energy for the process?
What will be the minimum pressure required to compress 500 dm3 of air at 1 bar to 200 dm3 at 30°C?
In a reaction A + B2 → AB2 Identify the limiting reagent, if any, in the following reaction mixtures.
(i) 300 atoms of A + 200 molecules of B
(ii) 2 mol A + 3 mol B
(iii) 100 atoms of A + 100 molecules of B
(iv) 5 mol A + 2.5 mol B
(v) 2.5 mol A + 5 mol B
At 0°C, the density of a certain oxide of a gas at 2 bar is same as that of dinitrogen at 5 bar. What is the molecular mass of the oxide?
Which one of the following will have largest number of atoms?
(i) 1 g Au (s)
(ii) 1 g Na (s)
(iii) 1 g Li (s)
(iv) 1 g of Cl2(g)
Density of a gas is found to be 5.46 g/dm3 at 27 °C at 2 bar pressure. What will be its density at STP?
Compare the alkali metals and alkaline earth metals with respect to
(i) ionization enthalpy
(ii) basicity of oxides and
(iii) solubility of hydroxides.
Fluorine reacts with ice and results in the change:
H2O(s) + F2(g) → HF(g) + HOF(g)
Justify that this reaction is a redox reaction.
How will you convert benzene into
(i) p - nitrobromobenzene
(ii) m - nitrochlorobenzene
(iii) p - nitrotoluene
(iv) acetophenone?
Equilibrium constant, Kc for the reaction
N2 (g) + 3H2 (g) ↔ 2NH3 (g) at 500 K is 0.061
At a particular time, the analysis shows that composition of the reaction mixture is 3.0 mol L–1 N2, 2.0 mol L–1 H2 and 0.5 mol L–1 NH3.
Is the reaction at equilibrium?
If not in which direction does the reaction tend to proceed to reach equilibrium?
Explain why alkali and alkaline earth metals cannot be obtained by chemical reduction methods?
While sulphur dioxide and hydrogen peroxide can act as oxidising as well as reducing agents in their reactions, ozone and nitric acid act only as oxidants. Why?
Calculate the enthalpy change on freezing of 1.0 mol of water at 10.0°C to ice at -10.0°C. ΔfusH = 6.03 kJ mol-1 at 0°C.
Cp[H2O(l)] = 75.3 J mol-1 K-1
Cp[H2O(s)] = 36.8 J mol-1 K-1
Which one of the alkaline earth metal carbonates is thermally the most stable?
(a) MgCO3 (b) CaCO3 (c) SrCO3 (d) BaCO3
How does H2O2 behave as a bleaching agent?
A 0.02 M solution of pyridinium hydrochloride has pH = 3.44. Calculate the ionization constant of pyridine
The right answer is 2.012Ã10^16
Yaah this is not the correct answer
This is not correct answer
Correct answer will be 2.012ÃÃ10^16 photons
Sir, the answer will be 2.014*10^16
this is shit
I have not understood nicely.....
Thank u.... for this solution...
Energy of photon will be 4.965 * 10^-17 and hence the answer will be 2.014 * 10^16 photons
Write but some corrections needed