How many molecules are present in 2.30 grams of NH_3?

• A. 1.36 × 10^{22} molecules
• B. 4.08 × 10^{21} molecules
• C. 2.04 × 10^{23} molecules
• D. 8.14 × 10^{22} molecules

Answer: (D)

Verified step by step guidance

1. First, calculate the molar mass of ammonia (NH_3). Use the atomic masses: nitrogen (N) is approximately 14.01 g/mol and hydrogen (H) is approximately 1.008 g/mol. The molar mass of NH_3 is calculated as \$14.01 + 3 \times 1.008$ g/mol.
2. Next, determine the number of moles of NH_3 in 2.30 grams by using the formula: \(\text{moles} = \frac{\text{mass}}{\text{molar mass}}\). Substitute the given mass (2.30 g) and the molar mass you calculated in step 1.
3. After finding the number of moles, use Avogadro's number to find the number of molecules. Avogadro's number is \$6.022 \times 10^{23}$ molecules per mole.
4. Calculate the number of molecules by multiplying the number of moles by Avogadro's number: \(\text{molecules} = \text{moles} \times 6.022 \times 10^{23}\).
5. Finally, compare your calculated number of molecules with the given options to identify the correct answer.