Which of the following samples contains the same number of atoms as 1 gram of He?

• A. 1 gram of H
• B. 2 grams of He
• C. 4 grams of He
• D. 1 gram of O

Answer: (C)

Verified step by step guidance

1. Identify the number of atoms in 1 gram of helium (He). To do this, first calculate the number of moles of He in 1 gram using the molar mass of helium: \(\text{moles} = \frac{\text{mass}}{\text{molar mass}} = \frac{1\ \text{g}}{4.00\ \text{g/mol}}\).
2. Calculate the number of atoms in 1 gram of He by multiplying the moles by Avogadro's number: \(\text{atoms} = \text{moles} \times 6.022 \times 10^{23}\) atoms/mol.
3. Repeat the process for each sample given (1 g of H, 2 g of He, 4 g of He, and 1 g of O) by calculating the moles for each using their respective molar masses (H = 1.00 g/mol, He = 4.00 g/mol, O = 16.00 g/mol).
4. Calculate the number of atoms in each sample by multiplying the moles by Avogadro's number, just like in step 2.
5. Compare the number of atoms calculated for each sample to the number of atoms in 1 gram of He to determine which sample contains the same number of atoms.