<u>Answer:</u>
<u>For a:</u> The wavelength of light is 
<u>For b:</u> The light is getting absorbed
<u>Explanation:</u>
To calculate the wavelength of light, we use Rydberg's Equation:

Where,
= Wavelength of radiation
= Rydberg's Constant = 
= Higher energy level = 7
= Lower energy level = 3
Putting the values in above equation, we get:

Hence, the wavelength of light is 
There are two ways in which electrons can transition between energy levels:
- <u>Absorption spectra:</u> This type of spectra is seen when an electron jumps from lower energy level to higher energy level. In this process, energy is absorbed.
- <u>Emission spectra:</u> 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.
Answer:
a. 0.182
b. 1.009
c. 1.819
Explanation:
Henderson-Hasselbach equation is:
pH = pKa + log [salt / acid]
Let's replace the formula by the given values.
a. 3 = 3.74 + log [salt / acid]
3 - 3.74 = log [salt / acid]
-0.74 = log [salt / acid]
10⁻⁰'⁷⁴ = 0.182
b. 3.744 = 3.74 + log [salt / acid]
3.744 - 3.74 = log [salt / acid]
0.004 = log [salt / acid]
10⁰'⁰⁰⁴ = 1.009
c. 4 = 3.74 + log [salt / acid]
4 - 3.74 = log [salt / acid]
0.26 = log [salt / acid]
10⁰'²⁶ = 1.819
10. You demonstrated the difference in density of the two objects. It is a physical property.
11. First calculate the density for all of them: density = mass/volume
Density:
A. 5/6 g/ml
B. 10/9 g/ml
C. 15/16 g/ml
D. 20/10 g/ml
If the density of the substance is higher than the density of the substance it is put in, then it will sink. So substances B and D will sink in water, as their densities are higher than 1 g/ml.
12. Ammonia weighs less than water does-- for example, the weight of 8 gallons of ammonia will be equivalent to the weight of 5 gallons of water.
Hope this helped!