sodium reacts completely with 0.142kg of chlorine, forming 234g of sodium chloride. What mass of sodium reacted?
I know that for chemical changes the amounts should end up being equal, but I don't know how to set up the problem.
92.0
92 is the correct answer.
92.0g
It is the number of atoms, or moles, of Na which is equal to the number of atoms, or moles, of Cl in NaCl
Na = 23 grams/mol
Cl = 35.5 grams/mol
NaCl = 58.5 grams/mol
so if we ended up with 234 grams ofNaCl, that was 4 mols of NaCl
That requires 4*23 = 92 grams of Na
and
That requires 4*35.5 = 142 grams of Cl, sure enough
92.0g
To solve this problem, we can use the concept of stoichiometry, which relates the amounts of reactants and products in a chemical reaction.
The balanced chemical equation for the reaction between sodium and chlorine is:
2Na + Cl2 -> 2NaCl
From the equation, we can see that 2 moles of sodium react with 1 mole of chlorine to produce 2 moles of sodium chloride.
Now, let's calculate the number of moles of sodium chloride formed using the given mass:
Mass of sodium chloride = 234 g
To convert this mass to moles, we need to use the molar mass of sodium chloride (NaCl), which is the sum of the atomic masses of sodium (Na) and chlorine (Cl). The atomic masses can be found on the periodic table.
Molar mass of NaCl = atomic mass of Na + atomic mass of Cl
Molar mass of NaCl = 23 g/mol + 35.5 g/mol = 58.5 g/mol
Number of moles of NaCl = mass of NaCl / molar mass of NaCl
Number of moles of NaCl = 234 g / 58.5 g/mol ≈ 4 moles
Since the balanced chemical equation shows that 2 moles of sodium react to form 2 moles of sodium chloride, we can conclude that the number of moles of sodium used is also 2 moles.
However, the problem asks for the mass of sodium, so we need to convert the moles of sodium to grams using the molar mass of sodium (Na).
The molar mass of sodium is given on the periodic table as 23 g/mol.
Mass of sodium = moles of sodium x molar mass of sodium
Mass of sodium = 2 moles x 23 g/mol = 46 g
Therefore, the mass of sodium that reacted is 46 grams.