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# A solution was made by dissolving 800.0 g of NaOH in 2.00L of water. ?

A solution was made by dissolving 800.0 g of NaOH in 2.00L of water. (answer is given show work to how you got the answer)

What is the Molality? Answer is 10mole/kg

Update:

What is the mole fraction? Answer is

NaOH=0.15 H2O=0.85

Update 2:

Mass % of NaOH answer is 28.6%

### 1 Answer

Relevance
• Molality is moles of solute per 1 kg of solvent.

In the case of water, molality is almost the same as molarity, because 1 liter of water has a mass of right around 1 kg.

The mass of 1 mole of NaOH is 23g + 16g + 1g = 40g, so the 800 grams of NaOH is 20 moles.  Hence you have 20 moles of solute per 2 kg of solvent (water), and the molality is 20/2 = 10 mol/kg.

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