Question

Without doing any calculations, determine which sample contains the most atoms.

a. one gram of lead

b. one gram of carbon

c. one gram of cobalt

Answer 1

One gram of carbon contains the most atoms compared to one gram of lead or cobalt since carbon has the lowest atomic mass of the three, allowing more atoms to be present per gram.

Step-by-step explanation:

To determine which sample contains the most atoms without doing any calculations, we consider the atomic mass of each element and how that relates to the mole concept. Elements with a lower atomic mass will have more atoms per gram than those with a higher atomic mass, as the mole (Avogadro's number, 6.022 × 10²³ atoms) of any element is equal to its atomic mass in grams.

Comparing lead (Pb), carbon (C), and cobalt (Co):

• Lead has a molar mass of about 207 g/mol.
• Carbon has a molar mass of about 12 g/mol.
• Cobalt has a molar mass of about 58.9 g/mol.

Since carbon has the lowest molar mass, one gram of carbon will contain more moles and, consequently, more atoms than one gram of lead or cobalt. Therefore, sample b. one gram of carbon contains the most atoms.