Calculate the change in the entropies of the system and the surroundings, and the total change in entropy, when the volume of a sample of argon gas of mass 21 g at 298 k and 1.50 bar increases from 1.20 dm3 to 4.60 dm3 in
(a) an isothermal reversible expansion,
(b) an isothermal irreversible expansion against pex = 0, and
(c) an adiabatic reversible expansion.

Which of the following elements is a representative element? a. chromium (cr) b. aluminum (al) c. mercury (hg) d. silver (ag)

As light moves from one material into the next, which of the following affects how much the light waves will refract, or bend? angle at which the ray strikes the medium color of the material density of the material temperature of the light wave

The image compares the arrangement of electrons in two different neutral atoms. a figure labeled atom q has a shaded sphere at the center of three concentric circles. the innermost circle has two black spheres. the middle circle has six black spheres. to the left of this figure is another figure labeled atom p. atom p has a shaded sphere at the center of three concentric circles. the innermost circle has two black spheres. the middle circle has seven black spheres. which of the following best explains the position of the two atoms in the periodic table? atom p has an estimated zeff of 7 and is therefore to the left of atom q, which has a zeff of 6. atom p has an estimated zeff of 7 and is therefore to the right of atom q, which has a zeff of 6. atom p has an estimated zeff of 5 and is therefore below atom q, which has a zeff of 4. atom p has an estimated zeff of 5 and is therefore above atom q, which has a zeff of 4.