As the temperature of a substance decreases, the
average kinetic energy of its particles
(1) decreases
(2) increases
(3) remains the same

Option (1) is the correct answer.

Explanation:

Kinetic energy is the energy that arises due to the motion of molecules. Average kinetic energy involves the sum of vibrational, translational and rotational kinetic energies.

When we decrease the temperature then the movement of molecules starts to decrease. As a result, there will be decrease in the average kinetic energy of its particles.

Thus, we can conclude that as the temperature of a substance decreases, the  average kinetic energy of its particles decreases.

1. for the first question, we must find the mass of the anhydrous salt, mgso₄. the molar mass for mgso₄·7h₂o is 246.47 g/mol, while that of mgso₄ is 120.37 g/mol.7.834 g mgso₄·7h₂o * 1 mol mgso₄·7h₂o/246.47 g * 1 mol mgso₄/1 mol mgso₄·7h₂o * 20.37 g mgso₄/mol = 0.647 g mgso₄

2. mass of water = mass of sample - mass of anhydrous salemass of water = 7.834 - 0.647 = 7.19 gpercent water in hydrate = 7.19/7.834 * 100 = 91.74%

the number of protons in the nucleus of a given element. has slight luster and conducts electricity at high temperatures like metal.but like a nonmetal,boron is brittle and does not conduct electricity well at low temperatures. in graphite, carbon is a soft,brittle solid.it is reflective,ductile,or malleable.