A mixture of 100g H2O and 100g NaNO, is prepared at 30C and the mixture is filtered. Will all of the salt dissolve? Yes or No. If not, what mass of NaNO, will be collected on the filter?

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ncchemist | eNotes Employee

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You have a typographical error in your question.  NaNO does not exist.  You mean either NaNO2 or NaNO3 (sodium nitrite or sodium nitrate).  Since you could conceivably be asking about either chemical, I will answer for both of them.

We need to find the solubility of the chemicals in water in order to figure out the answers.  There is no way to calculate the water solubilities of the compounds, we simply have to look them up.  The solubility of NaNO2 in water at room temperature is 84.8 g per 100 mL of water.  The solubility of NaNO3 in water at room temperature is 91.2 g per 100 mL of water.  Since the density of water is 1 g per mL, we know that 100 mL of water is the same as 100 g of water.  So now we can answer your question.

In terms of whether all of the salt will dissolve in 100 g of water, the answer is no for both compounds because they both have an aqueous solubility of less than 100 g per mL.  In the case of NaNO2, the mass of undissolved salt that will be collected on the filter will be 100-84.8=15.2 g.  In other words, 84.8 g of NaNO2 will dissolve in the water, leaving 15.2 g of undissolved solid.  In the case of NaNO3, the amount of solid collected in the filter will be 100-91.2=8.8 g.

To summarize:

For NaNO2: 15.2 g

For NaNO3: 8.8 g