Answer:
The pH would be 1.
Explanation:
The pH of an acid can be found by using the formula pH = - log [H⁺]. This was a method developed to be able to measure the pH of substances.
Since the concentration of HNO₃ is 0.1 M, then it also means that the concentration of H⁺ ions is 0.1 M.
By substituting for the formula: pH of 0.1 M HNO₃ = - log [0.1]
= 1
Answer:
n = 2.208x10¹⁸ photons
Explanation:
The energy of a photon( an elementary particle) is given by the equation:
E = nxhxf
Where n is the number of photons, h is plank constant (6,62x10⁻³⁴ J.s), and f is the frequency. Knowing that the power level is 0.120mW (1.2x10⁻⁴ W), the energy in J, for a time of 78 min (4680 s)
E = 1.2x10⁻⁴x4680 = 0.5616 J
The frequency of a photon is its velocity ( c= 3x10⁸ m/s) divided by its wavelength, which is 780 nm = 780x10⁻⁹ m
f = 3x10⁸/780x10⁻⁹
f = 3.846x10¹⁴ s⁻¹
Then, the number of photons is:
0.5616 = nx6,62x10⁻³⁴x3.846x10¹⁴
n = 2.208x10¹⁸ photons.
Answer:
the leaves i think
Explanation:
i had this on a test once.
Answer: There no chemical change, but there is a physical change.
Reason: When a substance dissolves in water, the substance retains its molecular identity and simply mixes throughout the water
Given :
Initial mass , a = 150 gm .
Half time ,
.
Final mass , x = 18.75 gm .
To Find :
The time taken to decay 18.75 gm .
Solution :
We know , time taken is given by :
Here , k is a constant given by :
Putting all given value in above equation :
We get :
Therefore , time taken is 6.94 hours .
Hence , this is the required solution .
