Question

Calculate how many grams of Salt may be produced from a 5.00 gram sample of Chlorine gas when combined with unlimited sodium metal.

Answer 1

@levinelevine @Kryten

Answer 2

First let's figure out the chemical reaction taking place. What would the balanced reaction be?

Answer 3

2 Na + Cl2 ----> 2 NaCl

Answer 4

I have the first part figured out @matt101 .

2 Na (s) + Cl2 (g) -----> 2 NaCl (s)

2 mol : 1 mol : 2 mol


Moles of Cl = grams of Cl * 1 mol Cl/ molar mass of Cl

Moles of Cl = 5.00 * 1 mol Cl/35.45 g/mol
Moles of Cl = .141

Answer 5

I'm just having a hard time figuring out the step that involves using the mole ratio.

Answer 6

Well you're on the right track. But keep in mind that you have 5.00 g of Cl2, not Cl, so the molar mass is not 35.45 g/mol but instead 70.9 g/mol. This means you have 0.0705 mol of Cl2.

As for the mole ratio, just set up an equation. According to the reaction, for every ONE mole of Cl2 reacted, TWO moles of NaCl are produced. We have 0.0705 mol of Cl2 reacted, so how many moles of NaCl are produced?

\[{2 \space NaCl \over 1 \space Cl_2} = {x \space NaCl \over 0.0705 \space Cl_2}\]
Solve for x and you have the moles of NaCl produced! Then just convert to grams and you're done!

Answer 7

@matt101 Is this right?

2 Na (s) + Cl2 (g) -----> 2 NaCl (s)

2 mol : 1 mol : 2 mol



Moles of Cl2 = grams of Cl * 1 mol Cl/ molar mass of Cl2
Moles of Cl2 = 5.00 * 1 mol Cl2/ 70.9 g/mol

Moles of Cl2 = .071



.071 Mol Cl * 2 mol NaCl / 1 Mol Cl2 = .142 Mol Cl2



Maximum Possible Amount of NaCl Produced with 5.00 g Cl2 = Moles of Cl2 * Molar Mass of Cl2

Maximum Possible Amount of NaCl Produced with 5.00 g Cl2 = .142 Mol Cl2 * 70.9 g/mol Cl2

Maximum Possible Amount of NaCl Produced with 5.00 g Cl2 = 10.1 g

Answer 8

You need to use the molar mass of NaCl if you want to find out the mass of NaCl produced.

Remember, we just found the moles of NaCl produced: 0.142 mol. Multiply this by the molar mass of NaCl (58.44 g/mol) to find the mass of NaCl produced. All the variables need to refer to the same compound, so you can't mix and match the molar mass of Cl2 with the moles of NaCl or your answer won't make sense.

Mass of NaCl = Moles of NaCl * Molar mass of NaCl = 0.142 mol * 58.44 g/mol = 8.30 g of NaCl produced