Answer:
Spectroscopy
Explanation:
They can determine its composition based on these wavelengths. The most common method astronomers use to determine the composition of stars, planets, and other objects is spectroscopy
The monochloroderivatives will be obtained by substituting chemically non equivalent hydrogen with chlorine atom, one by one
So the possible monochloro derivatives of 2,4-dimethylpentane (figure 1) are shown in figure (2)
Gay-Lussac's law gives the relationship between pressure and temperature of gas. For a fixed amount of gas, pressure is directly proportional to temperature at constant volume.
P/T = k
where P - pressure , T - temperature and k - constant

parameters for the first instance are on the left side and parameters for the second instance are on the right side of the equation
substituting the values in the equation

T = 4342 K
initial temperature was 4342 K