When a volatile liquid is in an open container, it evaporates. When a volatile liquid is in a closed container, it builds up vapor pressure. Vapor pressure is the function of the temperature of the system (an indication of the average kinetic energy of the particles) and the intermolecular forces holding the particles together in the liquid state. It represents a dynamic system, where the rate of liquid particles vaporizing to the gas phase is exactly equal to the rate of gas particles condensing to the liquid phase.
The properties of pure liquids are fascinating, but they become even more interesting when we add another component to the system. A solution is a homogeneous mixture of two or more components. The major component(s) is/are the solvent(s); the minor component(s) is/are the solute(s). When a solute dissolves in a solvent, solvent-solvent and solute-solute interactions must be broken (requires energy) and solvent-solute interactions must form (releases energy). If the energy released is greater than the energy required, a solution forms.
We also reviewed molarity and stoichiometry problems. All stoichiometry problems follow the same 4 steps:
1. Write a balanced chemical equation
2. Convert the quantity of the known compound(s) to moles
3. Using the mol-mol ratio in the balanced chemical equation, convert moles of known substance to moles of interest
4. Convert moles of interest to whatever you're looking for
Wow, big day. See you in lab tomorrow.
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