what is the following???
a qualitative observation is when somehthings appearance changes like form red to blue, and qualitative is when the umber of something changes.
Hope this helps
Kenny
Explanation:
hope this helps you..........
A chemical reaction is a process that leads to the transformation of one set of chemical substances to another. Classically, chemical reactions encompass changes that only involve the positions of electrons in the forming and breaking of chemical bonds between atoms, with no change to the nuclei (no change to the elements present), and can often be described by a chemical equation.
Answer: 
.
Explanation:
= Wavelength of radiation
E= energy
Using Rydberg's Equation:
Where,
= Wavelength of radiation = ?
= Rydberg's Constant
= Higher energy level = 4
= Lower energy level = 1
Z= atomic number = 1 (for hydrogen)
Putting the values, in above equation, we get
The relationship between wavelength and frequency of the wave follows the equation:
where,
= frequency of the wave = ?
c = speed of light = 
= wavelength of the wave = 
The frequency of the light emitted by a hydrogen atom during a transition of its electron from the n = 4 to the n = 1 principal energy level is .
Answer: i think its the thired one
Explanation:
