St. Louis, Missouri, is located near the middle of the United States. On June 21, the noon Sun rays hit St. Louis at an angle of 75°. On December 21, the noon Sun rays hit at an angle of 28°. How will this affect the temperature in St. Louis on these dates?

The temperature will be colder on December.

Explanation:

It is given that the angle of the sun rays on June 21st on St. Louis, Missouri hits at 75° angle. And on December 21st, the sun rays are at an angle of 28°.

Now, St. Louis, Missouri is located in the middle of United States which is in the Northern hemisphere.

From here, we can conclude that the temperature of St. Louis, Missouri on December 21st will be much colder as the rays of the Sun is at a much lower angle on the surface than on the 21st June. Due to this lower angle of the sun rays, the energy of the sun will be more spread out and will be less concentrated on the surface on 21st December when compared to 21st June. Also the days are much shorter in December than in June.

the formula mass of a molecule or a compound is the sum of the atomic weights of the atoms in its empirical formula

(that's what i know about formula mass)