<u>Answer:</u> The wavelength of spectral line is 656 nm
<u>Explanation:</u>
To calculate the wavelength of light, we use Rydberg's Equation:
Where,
= Wavelength of radiation
= Rydberg's Constant = 
= Final energy level = 2
= Initial energy level = 3
Putting the values in above equation, we get:
Converting this into nanometers, we use the conversion factor:
So, 
Hence, the wavelength of spectral line is 656 nm
A. They speed up chemical reactions
Mass of water : 0.45 g
<h3>Further explanation</h3>
Given
1.5 g ethanoic acid
Required
Mass of water
Solution
Reaction
<em>CH₃COOH + NaOH ⇒H₂O + CH₃COONa</em>
mol CH₃COOH(MW=60 g/mol) :
= mass : MW
= 1.5 : 60
= 0.025
mol H₂O from the equation :
= 0.025(mol ratio CH₃COOH : H₂O= 1 : 1)
Mass of water :
= mol x MW water
= 0.025 x 18 g/mol
= 0.45 g
A. Amount of sleep, since it depends on how much coffee she drinks
