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For the reaction represented by the equation 2na + 2h2o ® 2naoh + h2, how many grams of hydrogen are produced if 120. g of sodium and 80. g of water are available?

Respuesta :

JavierCollante
how much of a product is made depends on the limiting reagent. there are different ways to determine the limiting reagent and this depends on the professor way of teaching it. I will use the must common one. so keep in mind that the way to solve this problem may vary. 

first we convert each grams to moles using the molar mass of the molecules. then convert moles to moles of asked molecule (H2O) using the mole-mole ration, and moles of water to grams using the molar mass of water. 

molar mass of Na= 23.0 g/mol
molar mass of H₂O= 18.0 g/mol

ratios (based on the balanced equation coefficients)
2 mol Na= 1 mol H₂
2 mol H₂O= 1 mol H₂

calculations:
[tex]120. g Na \frac{1 mol Na}{23.0 g} x \frac{1 mol H_{2} }{2 mol Na} x \frac{2.02 g}{1 mol H_2} = 5.27 g H_2[/tex]
[tex]80. g H_2 O \frac{1 mol H_2 O}{18.0 g} x \frac{1 mo H_2}{2 mol H_2 O} x \frac{2.02 g}{1 mol H_2} = 4.49 g H_2[/tex]

since H₂O gives less of the product than the other one. H₂O is the limiting reagent and the answer is 4.49 g

The grams of Hydrogen produced by the 120 grams Na and 80 grams of water is 4.44 grams.

The balanced chemical equation has been:

[tex]\rm 2\;Na\;+\;2\;H_2O\;\rightarrow\;2\;NaOH\;+\;H_2[/tex]

From 2 moles of sodium and 2 moles of water, 1 mole of hydrogen has been produced.

The limiting factor has been:

120 grams sodium will be:

Moles = [tex]\rm \dfrac{weight}{molecular\;weight}[/tex]

Moles of Na = [tex]\rm \dfrac{120}{23}[/tex]

Moles of Na = 5.217 mol

Moles of water = [tex]\rm \dfrac{80}{18}[/tex]

Moles of water = 4.44 mol

Since 5.217 moles of Na requires 5.217 moles of water, water has been the limiting reactant.

The moles of product = moles of limiting reactant

Moles of hydrogen produced = 4.44 mol

The molecular weight of hydrogen is 1g/mol.

Thus the grams of Hydrogen produced by the 120 grams Na, and 80 grams of water is 4.44 grams.

For more information about the reaction equation, refer to the link:

https://brainly.com/question/1363213