How many moles of sodium atoms are in 5 g of sodium carbonate?
The Correct Answer and Explanation is:
To find the number of moles of sodium atoms in 5 g of sodium carbonate (Na₂CO₃), we need to follow these steps:
Step 1: Calculate the molar mass of sodium carbonate (Na₂CO₃)
The molar mass of Na₂CO₃ can be calculated by adding the atomic masses of all the atoms in the compound. The atomic masses of sodium (Na), carbon (C), and oxygen (O) are:
- Sodium (Na) = 22.99 g/mol
- Carbon (C) = 12.01 g/mol
- Oxygen (O) = 16.00 g/mol
For Na₂CO₃:
- Sodium (Na) contributes: 2 × 22.99 = 45.98 g/mol
- Carbon (C) contributes: 1 × 12.01 = 12.01 g/mol
- Oxygen (O) contributes: 3 × 16.00 = 48.00 g/mol
Therefore, the molar mass of Na₂CO₃ is: 45.98+12.01+48.00=105.99 g/mol45.98 + 12.01 + 48.00 = 105.99 \, \text{g/mol}45.98+12.01+48.00=105.99g/mol
Step 2: Convert the mass of sodium carbonate to moles
Now, we can convert the given mass of Na₂CO₃ (5 g) to moles using the molar mass: moles of Na₂CO₃=mass of Na₂CO₃molar mass of Na₂CO₃=5 g105.99 g/mol≈0.0471 mol\text{moles of Na₂CO₃} = \frac{\text{mass of Na₂CO₃}}{\text{molar mass of Na₂CO₃}} = \frac{5 \, \text{g}}{105.99 \, \text{g/mol}} \approx 0.0471 \, \text{mol}moles of Na₂CO₃=molar mass of Na₂CO₃mass of Na₂CO₃=105.99g/mol5g≈0.0471mol
Step 3: Determine the number of moles of sodium atoms
In one mole of sodium carbonate (Na₂CO₃), there are 2 moles of sodium (Na) atoms because the chemical formula has two sodium atoms per formula unit of Na₂CO₃. So, to find the moles of sodium atoms, we multiply the moles of Na₂CO₃ by 2: moles of Na=2×0.0471 mol=0.0942 mol\text{moles of Na} = 2 \times 0.0471 \, \text{mol} = 0.0942 \, \text{mol}moles of Na=2×0.0471mol=0.0942mol
Final Answer:
There are approximately 0.0942 moles of sodium atoms in 5 g of sodium carbonate.
This calculation is based on the molar mass of Na₂CO₃ and the stoichiometric relationship between sodium and sodium carbonate.
