** asap ! **
how can astronomers determine a star’s chemical composition?
a. by looking at its temperature
b. by using a spectrograph
c. by comparing its size to the sun
d. by comparing its color to the sun

electromagnetic waves travel through space with vacuums. give me brainliest if right.

answer: 802.3 kilo joules of energy represents 191.75 kilo calorie of energy.

explanation:

energy released during combustion of one mole methane = 802.3 kilo joules

if 1 kilo joule = 0.239006   kilo calorie

then ,802.3 kilo joule will be = 802.30.239006 kilo calorie

802.3 kilo joule = 191.75 kilo calorie

hence, the energy in kilo calorie is 191.75 kilo calorie.