Question

Which of the following weighs the least?
(a) 2 g atom of N (b) $3\times {10}^{25}$ atoms of carbon
(c) 1 mole fo sulphur (d) 7 g silver

Answer 1

Convert all the values to right unit, it means to convert all to mass in grams.

(a) $2gatomofN=2gramsatomN\times \frac{14gN}{1gramatomN}=28gramsN$

b) $3\times {10}^{25}atomsofcarbon=3\times {10}^{25}atoms\times \frac{12gC}{6.023\times {10}^{23}atoms}=597.70gramsC$

c) 1 mole of sulphur = 1 mol x 32 g/mol = 32.0 grams S

(d) 7.0 g silver

Answer: Compare to all the atom masses, the Silver has least mass value, 7.0 grams.