ap_chem:solutions_molarity

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====== Solutions and Molarity ======
=== Solvent ===
The substance that is more plentiful in a solution
=== Solute ===
The substance that is less plentiful in a solution
=== Solution ===
A homogeneous mixture of two or more substances
===== Molarity =====
Molarity is the most common method to represent the concentration of solute particles in solution.
$\text{Molarity} = \frac{\text{mol solute}}{\text{L solution}}$

==== Example ====
> A 3.75g sample of NaCl is dissolved in water. The total volume of the solution is 768mL. What is the molarity of the solution?
$3.75\text{g NaCl} \times \frac{1 \text{ mol NaCl}}{58.44 \text{ g NaCl}} = 0.0642 \text{ mol NaCl}$

$\text{Molarity} = \frac{0.0642 \text{ mol}}{0.768 \text{ L}} = 8.36\times10^{-2} \text{ M NaCl}$

===== Electrolytes =====
When ionic compounds dissolve in water, it dissociates. These are known as electrolytes.

Common electrolytes include:
  * NaCl (salt)
  * NaNO<sub>3</sub> (sodium nitrate)
  * CaCl<sub>2</sub> (calcium chloride)

===== Dilutions =====
Lowering the concentration of solution (by adding more solvent). To determine the concentration of a solution, you can use the Dilution Equation.

$M_1V_1 = M_2V_{total}$

Note that $M*V = \text{moles}$. $M$ represents molarity and $V$ volume.

==== Example ====
What if a 1M 10mL solution was diluted with 10mL extra water?
  * $1M \times 10\text{mL} = ?M \times 20\text{mL}$
  * $M = 0.5M$ The result is a halved molarity!

Trace:

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