Chem Lab discussion:

Experiment 1: Salty Waters

Why Substance dissolve?

1.) Interaction of solute and solvent to form solvated particles
2.) Reaction of solute and solvent to form a new substance that becomes solvated
3.) Tendency of systems to attain maximum disorder

What is common to us is the solute is solid while the solvent is liquid

- there is solute solute interaction initially (ex. Salt has crystal formation)
- there is also solvent solvent interaction
- If the interaction between solute solvent is greater than the solute solute and the solvent solvent a solution will be made

Solvated – when the solute particles are surrounded by the solvent

Ex. H2O – because of the partial charges each molecule has and because of the partial changes salt has

There will be a point when Na+ solutes will be surrounded by solvent (H2O) molecules

GENERAL RULE: Like dissolves like
Ex. Polar substances will only dissolve polar substances

Everything in life tends to achieve the maximum state of disorder
- One cannot achieve order with disorder

Factors that influence solubility:
1.) Nature of solute and solvent
2.) Temperature (higher temp means the solute dissolves faster), increasing temp tends to dissolve the solute faster, but there are some solutes that do not dissolve faster (ex. Ammonium Chloride) when temp is higher--→
Exothermic reaction – outside (will expel or remove heat) (higher temp slower rate of solubility)
Endothermic – inside (will require heat – increased temp means faster solubility)
*Depends whether a chemical reaction will require heat
3.) Pressure – does not affect solid and liquid that much
- has a great affect on gases
- decrease pressure, decrease solubility o Ex. Soft drinks – sealing soft drinks builds up pressure

*In general, temp is directly related to solubility
* pressure is indirectly related to solubility in gases

Concentration Units:
1.) Percentage
% = raw/ total x 100 expressed g/g, g/mL, mL/mL
% = g/mL solute // g/mL solution x100
2.) Mole Fraction (x)
- similar to percentage without the times 100
- XASolute= moles of solute/ moles of solution
Ex. 1 mole of Carbon = 12.011 g C 1 mole HCl = 36.45 g HCl

Xb= mole of solvent/ moles of solution (has no unit)
- adding fractions shou0202ld be equal to one (ex. Mole of solvent – 0.2, other – 8.0)
M (morality) = moles of solute/ L of solution; m (molality) = moles of solute/ kg og Solvent

N = (weight of solute/ MW x number of eq) // L of solution

Ex. Na+Cl- = 1 Ca-2O

3.) Molarity
4.) Molality
5.) Normality

Experiment 1: salty waters
Evaporation
- a process by which liquid water is converted to vapor
- wind speed, temp, and humidity affect the rate of evaporation o high wind speed and temp high ROE o High humidity low ROE

BP of water: 100*C
BP of NaCl -: 1413 *C

Other ways to separate:
- Dist

Experinent 2: Conservation of Mass
- The total mass of all products is equal to the total mass of all reactants in a closed system

Nac2CO3 → NacCl + CaCO3
NaCl + CaCO23 ___> + H2SO4 → CaSO4 + H2O + CO2

Experiment 3: Layering Liquids
1.) Density – objects mass per unit volume
- intensive property
- Specifica gratity
2.) Miscibility
- the property of liquids to mix in all proportions forming a homogeneous solution

Experiment 4: Paper chromatography
- Chromotography is a separation techniquw
- Separation depends on how strongly the component so f the mixture are absorbed (stuck in the process) on the stationary phase of how reality they dissolve in the mobile phase (inisde na)
- Retention factor (Rf) = distance traveled by solute/ distance traveled by solvent

1.) Liquid Chroma – separates liquid samples with a liquid solvent (mobile phase) and a column composed of solid beads (stationary phase)
2.) Gas chroma – separates vaporized samples with a carrier gas (mobile phase) and a