Answer:
3.025eV
Explanation:
Energy of a photon is given by
E=hν
Where h is the Planck's constant
And ν represents the frequency of the photon .
Now for violet light wavelength λ=410nm= 410x10^-9m
By using the formula ν=c/λ
where c represents speed of light I.e 3 x 10^8 m/s
Calculating energy of violet photon we have
E=hc/λ
h=6.626 x 10^-34 J.s
On inserting the value in the formula , we get
E= 4.848 x 10^-19 Joules
To convert it into electron volts we need to divide it by 1.602 x10^-19.
The final result what we have is E=3.026eV.
Note: the result calculated is according to the above value . result may vary according to the values taken .
The amount of sample that is left after a certain period of time, given the half-life, h, can be calculated through the equation.
A(t) = A(o) (1/2)^(t/d)
where t is the certain period of time. Substituting the known values,
A(t) = (20 mg)(1/2)^(85.80/14.30)
Solving,
A(t) = 0.3125 mg
Hence, the answer is 0.3125 mg.
Answer:
A) 22.4L
Explanation:
we know, ideal gas law states
PV=nRT
V=nRT/P
At STP,
T= 273.15K P=1atm R=0.082L.atm/mol/K n=1 mole
V=(1*0.082*273.15)/ 1
V=22.4L
Answer:
CH3COOH would be more concentrated
Explanation:
The higher the concentration value, the more concentrated it is.
The relationship between concentration, moles and volume is given by the equation;
Concentration = No of moles / Volume
5.0 grams of HCOOH dissolved in 189 mL of water
Number of moles = Mass / Molar mass = 5 / 46.03 = 0.1086 mol
Concentration = 0.1086 / 0.189 = 0.5746 mol/L
1.5 moles of CH3COOH dissolved in twice as much water
Volume = 2 * 189 = 378 ml = 0.378 L
Concentration = 1.5 / 0.378 = 3.9683 mol/L
Comparing both concentration values;
CH3COOH would be more concentrated
