8. (05.03 MC) How does temperature influence the appearance of a star? Give an example in your response. (4 points)

Stars have the different colors that make up white light, the color of a star is related to the wavelength of the light which is emitted by the star which is related to the temperature of the star's surface

Very hot temperatures yield hotter wavelength, which light having short wavelength being bluish,  the blue and blue-white stars are the hottest stars, while stars which emit longer wavelength and therefore have a color of brown and red have a cooler surface temperature

The surface temperature of a star also has an effect on the bright appearance of a star. The higher the temperature of a star the higher the heat energy given off and the brighter the star will be, as a star that gives off more energy is brighter than one that gives less energy

Explanation:

part 1: the half-life of the element is 22 years.

part 2: it will take 132.02 year for the sample to decay from 308.0 g to 4.8125 g.

explanation:

part 1: there are two ways to determine the half life time.

first way: the half life time can be determined directly from its definition as it is the time required for the sample to decay to its half concentration.

from the data the initial concentration was 45.0 g and decayed to its half value (22.5 g) in 22.0 years.

second way: the radio active decay is considered first order reaction so we can use the laws of first order reactions.

k = (1/t) ln (a/a-x), where k is the rate constant of the reaction,

t is the time of the reaction

a is the initial concentration of the reactant

a-x is the remaining concentration at time (t)

a = 45.0 g the initial concentration at t = 0 year.

at t = 22 year, a-x = 22.5 g

then k = (1/22 year) ln (45.0 g/ 22.5 g) = 0.0315 year-1.

the half-life time (t1/2) = ln 2/ k = 0.693/ k =0.693/ 0.0315 = 22 years.

part 2:

using the same law k = (1/t) ln (a/a-x),

using the given data; a = 308.0 g and a-x = 4.8125 g and the calculated k from the part 1 (k = 0.0315 year-1)

t = (1/k) ln (a/a-x) = (1/0.0315) ln (308.0/ 4.8125) = 132.02 years

3 1/4 %

explanation: