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27 votes
27 votes
Which sample contains the greatest number of atoms?

(a) 27.2 g cr
(b) 55.1 g ti
(c) 205 g pb

User Pbojinov
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2 Answers

14 votes
14 votes

Final answer:

The sample with 55.1 g of titanium contains the most atoms as it has the greatest number of moles, determined by dividing the mass of the sample by the atomic weight and comparing the result among all samples.

Step-by-step explanation:

To determine which sample contains the greatest number of atoms, we need to calculate the number of moles in each sample and then use Avogadro's number (6.022 × 10²23 atoms/mol) to find the total number of atoms. The molar mass (g/mol) of each element is needed for this calculation and is approximately equal to the atomic weight of the element listed on the periodic table:

  • Chromium (Cr) has an atomic weight of about 52 g/mol.

  • Titanium (Ti) has an atomic weight of about 48 g/mol.

  • Lead (Pb) has an atomic weight of about 207 g/mol.

Using these molar masses, we calculate the number of moles for each sample:

  • a. 27.2 g Cr divided by 52 g/mol = 0.523 moles of Cr
  • b. 55.1 g Ti divided by 48 g/mol = 1.148 moles of Ti
  • c. 205 g Pb divided by 207 g/mol = 0.990 moles of Pb

Since all elements have the same number of atoms per mole, the sample with the most moles will also have the most atoms. Therefore, the sample containing 55.1 g of titanium (Ti) has the most atoms.

User Ekochergin
by
2.7k points
10 votes
10 votes

Answer:

b option is correct

Step-by-step explanation:

User Ermal
by
2.9k points