Question

lola adds 29 grams of sodium nitrate (nano₃) into 25 grams of water (h₂o) at 40°c. she stirs the mixture until no more nano₃ dissolves in the water, producing a saturated solution. approximately what mass of nano₃ remains undissolved?
write your answer as a whole number. round if necessary.
____ grams

Explanation:

Step1: Find solubility of NaNO₃ at 40°C

From the graph, solubility of $\text{NaNO}_3$ at $40^\circ\text{C}$ is $102\ \text{g per }100\ \text{g}\ \text{H}_2\text{O}$.

Step2: Calculate dissolved mass in 25g water

Use proportionality: $\text{Dissolved mass} = 102 \times \frac{25}{100}$
$\text{Dissolved mass} = 25.5\ \text{g}$

Step3: Find undissolved mass

Subtract dissolved mass from added mass: $\text{Undissolved mass} = 29 - 25.5$
$\text{Undissolved mass} = 3.5\ \text{g}$

Step4: Round to whole number

Round $3.5$ to the nearest whole number.

Answer:

4 grams