Answer:
The correct answer is option c.
Explanation:
Formula used to determine an average atomic mass :

Mass of isotope Sb-121 = 120.904 amu
Fractional abundance of Sb-121 = 57.21% = 0.5721
Mass of isotope Sb-123 = 122.904 amu
Fractional abundance of Sb-123 = 42.79% = 0.4279
Average atomic mass of Sb:

Answer:
a: chemical change because the change cannot be reversed.
b: physical change because the action can be reversed.
c: chemical change.
d:chemical change.
any change that cannot be reversed is a chemical change and any change that can be reversed is a physical change.
The correct answer for the following questions that are presented above are these ones:
(1) b. Pressure. The <span>physical effect can change the boiling point of a substance is the pressure.
(2) </span><span>Evaporation only occurs at the surface of a liquid. TRUE.</span><span>
(3) </span>d. freezing. The change from liquid to solid, or the reverse of melting, is called freezing.
Answer:
B
Explanation:
The tendency of a liquid to convert to vapour increases smoothly with increasing temperature. Vapour pressure shows the tendency of a liquid to convert to vapour. Increase In vapour pressure shows an increased tendency to convert to vapour. The higher the temperature, the higher the vapour pressure.
First one??
I believe this is the correct answer