Question

Six grams of carbon (C) and four grams of oxygen (O) contain:
a) twice as many carbon atoms as oxygen atoms.
b) 1.5 times as many carbon atoms as oxygen atoms.
c) the same number of atoms.
d) twice as many oxygen atoms as carbon atoms.

Answer 1

Molar mass of C = 12.01 g/mol

mass of C = 6 g

we have below equation to be used:

number of mol of C,

n = mass of C/molar mass of C

=(6.0 g)/(12.01 g/mol)

= 0.4996 mol

we have below equation to be used:

number of atoms of C = number of moles * Avogadro’s number

= 0.4996 * 6.022*10^23 atoms

= 3.00*10^23 atoms

Molar mass of O = 16 g/mol

mass of O = 4 g

we have below equation to be used:

number of mol of O,

n = mass of O/molar mass of O

=(4.0 g)/(16 g/mol)

= 0.25 mol

we have below equation to be used:

number of atoms of O= number of moles * Avogadro’s number

= 0.25 * 6.022*10^23 atoms

= 1.50*10^23 atoms

Answer: a