10th Class Chemistry Fundamentals

Study Notes

Distillation is the best technique for separating liquids with different boiling points
Distillation works by separating liquids based on their boiling points, with the liquid having the lower boiling point vaporizing first
If the boiling points are the same, distillation is not effective

Physical changes:
- NaCl dissolving in water (salt remains salt, just dissolved)
- An apple being cut (apple is still apple, just in smaller pieces)
- Heat changing H2O to steam (water changes state, but is still water)
- Alcohol evaporating (alcohol changes state, but is still alcohol)
- Ice melting (water changes state, but is still water)
Chemical changes:
- Ag tarnishing (silver reacts with sulfur to form silver sulfide)
- Baking soda reacting to vinegar (new substances formed, gas released)
- Fe rusting (iron reacts with oxygen to form iron oxide)

Physical properties:
- Color (e.g., blue)
- Density
- Solubility
- Melting point
- Luster
Chemical properties:
- Flammability
- Reacting with acid
- Supporting combustion

Elements:
- Gold (Au)
Compounds:
- Salt (NaCl)
- Pure Water (H₂O)
Solutions (homogeneous mixtures):
- Salt Water
- Steel (iron and carbon)
- Gatorade
Heterogeneous mixtures:
- Sand
- Soil
- Italian salad dressing
- Chocolate Chip Cookie
- Fruit Pebbles cereal

NaCl (salt) dissolves in water, remaining salt, but in a dissolved state, making it a physical change.
Silver (Ag) tarnishes when it reacts with sulfur to form silver sulfide, a new substance, making it a chemical change.
Cutting an apple into smaller pieces is a physical change, as the apple remains an apple, just in a different form.
Heating water (H2O) to produce steam is a physical change, as the water changes state but remains water.
Mixing baking soda with vinegar results in a chemical change, as new substances are formed and gas is released.
Rusting of iron (Fe) occurs when it reacts with oxygen to form iron oxide, a new substance, making it a chemical change.
Evaporation of alcohol is a physical change, as it changes state but remains alcohol.
Melting of ice to form water is a physical change, as water changes state but remains water.