<u>Given</u>:
Wavelength (λ) of the laser pulse = 545 nm = 5.45 * 10⁻⁹ m
Total energy of pulse = 4.85 mJ
<u>To determine:</u>
The number of photons in the laser of a given energy
<u>Explanation:</u>
Energy per photon (E) = hc/λ
where h = planck's constant = 6.626 *10⁻³⁴ Js
C = speed of light = 3*10⁸ m/s
λ = wavelength
E = 6.626 *10⁻³⁴ Js* 3*10⁸ms-1 /5.45 * 10⁻⁹ m = 3.65 * 10⁻¹⁹ J
Now,
# photons = total energy/Energy per photon
= 4.85 * 10⁻³ J* 1 photon / 3.65 * 10⁻¹⁹ J = 1.32 * 10¹⁶ photons
Ans: the laser pulse contains 1.32 * 10¹⁶ photons
Answer:
Acceleration:
Speed/Time
Change in speed or velocity over a specific amount of time
Speed:
Distance/Time
Change in distance over a specific amount of time
Velocity:
Distance/Time
Speed in a given direction
A 0.50 M solution of a monoprotic acid HA with a pH of 2.24 would be, first, a weak acid, as it does not dissociate fully. This leaves us with an equilibrium expression: HA (aq) <span>⇌ H+ (aq) + A- (aq)
Where A- is the conjugate base of the weak acid.
In a study of equilibrium, we remember that the ka value is the acid dissociation constant, and has the equation:
Ka = (concentration of H+)(concentration of conjugate base)/concentration of acid
We know the concentration of H+ and A- are 10^-2.24 by the definition of a pH being the -log(concentration of H+).
The concentration of the acid has gone down a little bit, as it has partially dissociated into H+ and A-, so we'll have to subtract 10^-2.24 from 0.50 for the concentration of the acid to account for the dissociation.
The final equation would then become:
[H+]*[A-]/[HA] = Ka
(10^-2.24) * (10^-2.24) / (0.50 - 10^-2.24) = Ka
(3.31 * 10^-5) / (0.494) = Ka
Ka = 6.70 * 10^-5</span>
1. 0.33 M
2. 0.278 M
<h3>Further explanation</h3>
Molarity is a way to express the concentration of the solution
Molarity shows the number of moles of solute in every 1 liter of solute or mmol in each ml of solution
Where
M = Molarity
n = Number of moles of solute
V = Volume of solution
1. 0.350 mol of NaOH in 1.05 L of solution.
n=0.35
V=1.05 L
Molarity :
2. 14.3 g of NaCl in 879 mL of solution.
mol NaCl(MW=58.5 g/mol) :
Molarity :