For an alloy that consists of 78.2 g copper, 103.5 g zinc, and 2.8 g lead, what are the concentrations of (a) Cu, (b) Zn, and (c) Pb in weight percent? The atomic weights of Cu, Zn, and Pb are 63.54, 65.39, and 207.2 g/mol, respectively.

Explanation:

Mass percent is defined as the mass of an element divided by the sum of masses of all the elements multiplied by 100. It is generally used to define the concentration. It does not depend on concentration.

It is given as;

Mass percent = (mass of an element / Total mass of the compound ) × 100

Mass of  compound (alloy) = 78.2 g copper  + 103.5 g zinc +2.8 g lead = 184.5 g

(a) Cu

Mass of Cu = 78.2

Mass percent = (78.2 / 184.5) * 100 = 42.38%

(a) Zn

Mass of Zn = 103.5

Mass percent = (103.5 / 184.5) * 100 = 56.10%

(c) Pb

Mass of Pb = 2.8

Mass percent = (2.8 / 184.5) * 100 = 1.52%

both adhesion and cohesion are attractions.

they are different in that adhesion is the force of attraction between the molecules of two different substances, whereas cohesion is the force of attraction between molecules of the same substance.

possible examples include capillary action, in which the adhesion between water and glass causes the water to rise in a narrow tube against the force of gravity.

because of hydrogen bonding, water is extremely cohesive.

this causes molecules on the surface of water to be drawn inward, which is why drops of water form beads on smooth surfaces.

hope this .

answer; the numbers of valence electrons in the acetic acid molecule (ch3co2h) is 24;