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3 years ago

A substance with a pH of 4.0?

Chemistry

2 answers:

IrinaVladis [17]3 years ago

7 0

Tomato juice or acid rain

Anna35 [415]3 years ago

7 0

Phosphoric acid is a substance with a pH of 4.0

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Consider a transition of the electron in the hydrogen atom from n=3 to n=7.

kow [346]

Answer:

For a: The wavelength of light is $1.005\times 10^{-6}m$

For b: The light is getting absorbed

Explanation:

For a:

To calculate the wavelength of light, we use Rydberg's Equation:

$\frac{1}{\lambda}=R_H\left(\frac{1}{n_i^2}-\frac{1}{n_f^2} \right )$

Where,

$\lambda$ = Wavelength of radiation

$R_H$ = Rydberg's Constant = $1.097\times 10^7m^{-1}$

$n_f$ = Higher energy level = 7

$n_i$ = Lower energy level = 3

Putting the values in above equation, we get:

$\frac{1}{\lambda }=1.097\times 10^7m^{-1}\left(\frac{1}{3^2}-\frac{1}{7^2} \right )\\\\\lambda =1.005\times 10^{-6}m$

Hence, the wavelength of light is $1.005\times 10^{-6}m$

For b:

There are two ways in which electrons can transition between energy levels:

Absorption spectra: This type of spectra is seen when an electron jumps from lower energy level to higher energy level. In this process, energy is absorbed.
Emission spectra: This type of spectra is seen when an electron jumps from higher energy level to lower energy level. In this process, energy is released in the form of photons.

As, the electron jumps from lower energy level to higher energy level. The wavelength is getting absorbed.

6 0

4 years ago

The human eye has an osmotic pressure of 8. 00 atm at 37. 0 °c. what concentration (in moles/l) of a saline (nacl) solution will

Gelneren [198K]

0.3147 concentration (in moles/l) of a saline (NaCl) solution will provide an isotonic eyedrop solution.

Isotonic eye drops

Because it might result in eye discomfort or tissue damage if it is not maintained, isotonicity is regarded as a crucial component of ophthalmic medicines. A few drops of blood are mixed with the test preparation before being examined and judged under a microscope at a magnification of 40. Isotonic solutions are those that have the same amount of water and other solutes in them as the cytoplasm of a cell. Since there is no net gain or loss of water, placing cells in an isotonic solution will not cause them to either shrink or swell.

We can calculate the osmotic pressure exerted by a solution using the following expression.

π = M . R . T

where,

π is the osmotic pressure

M is the molar concentration of the solution

R is the ideal gas constant

T is the absolute temperature

The absolute temperature is 37 + 273 = 310 K

π = M . R . T

8 = (X mol/L) . (0.082atm.L/mol.K) . 310 K = 0.3147 mol/L

To learn more about osmotic pressure refer:

brainly.com/question/5041899