# Calculate the mass in grams of 0.000025 Avagadro's number of rhodium atoms.

## Question:

Calculate the mass in grams of 0.000025 Avagadro's number of rhodium atoms.

## Avogadro's Number

The number of atoms in a mole of an element is specified, and is equal to {eq}6.022 \times 10^{23} {/eq}. For 1 mole of compounds, we do not speak of atoms but of molecules. Similarly, we can refer to 1 mole of ions, 1 mole of photons, electrons, etc.

## Answer and Explanation:

We have {eq}0.000025 \times N_A {/eq} atoms of rhodium. How many moles of rhodium are these? Dividing through by {eq}N_A {/eq}, we directly obtain 0.000025 moles. Now, the molar mass of rhodium is 103 g/mol. We can now compute the mass in grams:

{eq}0.000025 \ mol \times 103 \ g/mol =2.575 \times 10^{-3} \ g {/eq}

#### Learn more about this topic:

How to Convert Grams to Moles

from Analytical Chemistry: Help & Review

Chapter 4 / Lesson 8
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