A substance has a freezing point of 24 °C. Which of the following is true for the substance? a. When the substance is heated, its temperature will start rising above 24 °C after 50% of the liquid has changed to vapors. b. When the substance is heated, its temperature will start rising above 24 °C after 100% of the solid has changed to liquid.
c. When the substance is cooled, its temperature will fall below 24 °C after 100% of the vapors have changed to liquid.
d. When the substance is cooled, its temperature will fall below 24 °C after 50% of the liquid has changed to solid.

first let us lay out the formula for potential

and kinetic energy:

pe = mgh

ke = (mv^2)/2

where: m=mass, v=velocity, g=gravitational

acceleration, h=height

calculating for mass using the known values of

pe:

340j = m (9.81 m/s^2) (50ft) (1m/3.28ft)

m = 2.27 kg

the law of conservation of energy states that

energy is neither created nor destroyed. therefore, the change in kinetic

energy from 50 ft to 35 ft would be equal to the change in potential energy

from 50 ft to 35 ft. however it would be opposite in signs since one is losing

while other is gaining.

ke(35ft) – ke(50ft) = - [ pe(35ft) – pe(50ft]

ke(50ft) = 0 since the brick is initially at rest

ke(35ft) = 340j - 2.27kg (9.81 m/s^2) (35ft)

(1m/3.28 ft)

ke(35ft)

= 102.38 j

atomic mass = 39

number of neutrons = 20

number of protons= 19

electronic configuration = 1s2 2s2 2p6 3s2 3p6 4s1

the number of electron in first shell = 2

number of electrons in n=3 shell = 8

points

explanation: