Question

Which of the following statements is correct?

(1) The mass of one mole of oxygen is 16.00 g.
(2) One mole of an ideal gas occupies 22.4 L at NTP.
(3) One mole of methane contains five atoms.
(4) All of the above are incorrect.

Answer 1

(4) All of these are incorrect.

Explanation:

(1)

For `"O"_2, M_text(r) = 32.00`.

∴ The mass of `"1 mol O"_2 = "32.00 g"`

Statement (1) is incorrect.

(2)

NTP is 1 atm and 20 °C.

The Ideal Gas Law is

`color(blue)(bar(ul(|color(white)(aa)pV = nRTcolor(white)(a/a)|)))" "`

∴ `V = (nRT)/p = (1 color(red)(cancel(color(black)("mol"))) × "0.082 06 L"·color(red)(cancel(color(black)("atm·K"^"-1""mol"^"-1"))) × 293.15 color(red)(cancel(color(black)("K"))))/(1 color(red)(cancel(color(black)("atm")))) = "24.06 L"`

Statement (2) is incorrect.

(3)

1 `"CH"_4` molecule contains 5 atoms.

`"1 mol CH"_4` contains `"N"_text(A)` molecules.

`1 color(red)(cancel(color(black)("mol CH"_4 color(white)(l)"molecules"))) × (N_text(A) color(red)(cancel(color(black)(color(white)(l)"molecules CH"_4))))/(1 color(red)(cancel(color(black)("mol CH"_4 color(white)(l)"molecules")))) × "5 atoms"/(1 color(red)(cancel(color(black)("molecule CH"_4)))) = 5N_text(A) color(white)(l)"atoms"`

Statement (3) is incorrect.

(4)

Statement (4) is correct because all the above are incorrect.