2Na + 2H2O---> 2NaOH + H2
Need to find the molecules of H2
Atomic wt o Na = 23
48.7 g of Na
48.71/23 = 2.12 mols Na
2.12/2 × 24. (WHERE DOES THE 24 COME FROM) = 25.44 dm^3 H. (PLEASE EXPLAIN THIS PART) = 1.06moles
1.06mols× 6.02×10^23 avagados number=
1.204 × 10^24 molecules
I understand this except where the 24 comes from and the dm^3 parts----please explain
Thank you.
the 24 is a sloppy way of doing unit conversion problems. Let me show you.
Volume of H2=molesH2*volumeH2/mole
=2.12molesNa*1moleH2/2molesNa*22.4dm^3/moleH2=1.06*22.4 dm^2 AT STP.
now, if you are not doing stp conditions, but rather using RTP, At RTP (room temperature and pressure), this volume is 24 dm3 (liters)
See why I called your calculations sloppy? without units, and conditions, it makes no sense.
In the given chemical equation, it is stated that 2 mols of Na will react to produce 1 mol of H2.
To determine the number of mols of H2 produced, we first calculate the number of mols of Na used. We are given that the mass of Na is 48.7 g, and its atomic weight is 23 g/mol. Therefore, we can calculate the number of mols of Na using the formula:
mols of Na = mass of Na / atomic weight of Na = 48.7 g / 23 g/mol ≈ 2.12 mols.
Since the stoichiometric ratio between Na and H2 is 2:1, the number of mols of H2 produced will be half of the mols of Na used.
mols of H2 = mols of Na / 2 = 2.12 mols / 2 ≈ 1.06 mols.
Now, to convert the mols of H2 to volume in dm^3, we use the ideal gas law equation:
V = nRT / P,
where V is the volume, n is the number of mols, R is the ideal gas constant (0.0821 L·atm/mol·K), T is the temperature in Kelvin, and P is the pressure in atmospheres.
Assuming standard temperature and pressure (STP), which is 273K and 1 atm, respectively, we can simplify the equation:
V = n × 22.4 L/mol.
Here, the number 22.4 L/mol is the volume occupied by 1 mol of an ideal gas at STP. Since 1 mol of any gas occupies 22.4 L, we can use this value to convert the number of mols of H2 to the volume occupied by H2 gas.
V = 1.06 mols × 22.4 L/mol ≈ 23.7 L or 23.7 dm^3.
So, the volume of H2 produced is approximately 23.7 dm^3.
Finally, to find the number of molecules of H2, we can use Avogadro's number (6.02 × 10^23) to convert from mols to molecules. The relationship is:
number of molecules = number of mols × Avogadro's number.
number of molecules = 1.06 mols × 6.02 × 10^23 ≈ 1.204 × 10^24 molecules.
Therefore, the number of molecules of H2 produced is approximately 1.204 × 10^24.