Answer:
A. He arranged the first periodic table.
Explanation:
Answer: it honestly depends.
Explanation:
It respresents the higher energy level than 627nm .
<h3>What is a emission line ? </h3>
Emission lines are the glowing hot gas emits lines of light whereas absorption line refers to the tendency of cool atmospheric gas to absorb the same line of light.Some lights produce dark band when the light passes through gas in the atmosphere . There are two line spectrum and absorption.
spectrum is an excitement of electrons from lower to higher energy levels and when it comes back it releases energy in the terms of colourful lights .
It represents the higher energy levels than 627nm because Energy is inversly proportional to wavelength .
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Answer: The empirical formula for the given compound is 
Explanation : Given,
Percentage of C = 38.8 %
Percentage of H = 16.2 %
Percentage of N = 45.1 %
Let the mass of compound be 100 g. So, percentages given are taken as mass.
Mass of C = 38.8 g
Mass of H = 16.2 g
Mass of N = 45.4 g
To formulate the empirical formula, we need to follow some steps:
Step 1: Converting the given masses into moles.
Moles of Carbon =
Moles of Hydrogen = 
Moles of Nitrogen = 
Step 2: Calculating the mole ratio of the given elements.
For the mole ratio, we divide each value of the moles by the smallest number of moles calculated which is 3.23 moles.
For Carbon = 
For Hydrogen = 
For Oxygen = 
Step 3: Taking the mole ratio as their subscripts.
The ratio of C : H : N = 1 : 5 : 1
Hence, the empirical formula for the given compound is 
Answer:
Phenolphthalein is an acid indicator, which means when we add water (pH 7) to it, it ionizes giving a pink color. We all know acid gives in solution. When we add phenolphthalein to acid due to the common ion effect concentration increases. turned the solution pink.
Explanation: