Fundamental Ideas Flashcards
(15 cards)
What is a mixture?
Two or more substances (elements or compounds) not chemically bonded.
Mixtures can contain various proportions of components.
Define a pure substance.
One type of particle only.
Pure substances can be elements or compounds.
What is filtration used for?
Separates insoluble solids from liquids (e.g., sand from water).
Filtration is a common technique in both laboratory and industrial processes.
What is crystallisation?
Separates a dissolved solid by evaporating the solvent (e.g., salt from saltwater).
Crystallisation is often used to purify substances.
What does simple distillation accomplish?
Separates solvent from solution (e.g., water from ink).
Simple distillation is effective for solutions where the solvent has a significantly lower boiling point than the solute.
What is fractional distillation?
Separates a mixture of liquids with different boiling points (e.g., ethanol and water).
Fractional distillation is used in the petroleum industry and to produce alcoholic beverages.
What technique does chromatography use?
Separates substances in a mixture based on how far they travel on paper.
Chromatography is widely used in chemistry for separating and analyzing mixtures.
What happens during evaporation?
Liquid → gas.
Evaporation occurs at any temperature and involves molecules at the surface of a liquid.
List the changes of state.
- Melting (solid → liquid)
- Freezing (liquid → solid)
- Evaporation/Boiling (liquid → gas)
- Condensation (gas → liquid)
- Sublimation (solid → gas)
Each change of state involves energy transfer and changes in particle arrangement.
Describe the particle arrangement in a solid.
Regular, close.
Solids maintain a fixed shape and volume due to strong intermolecular forces.
How do particles move in a liquid?
Slide.
Liquids have a definite volume but take the shape of their container due to weaker forces than in solids.
What is the arrangement of particles in a gas?
Far apart, random.
Gases fill the volume of their container and have very weak intermolecular forces.
True or False: The forces between particles in a gas are strong.
False.
Gases have weak intermolecular forces, allowing particles to move freely.
What is the movement of particles in a solid?
Vibrate.
In solids, particles are fixed in place and can only move slightly due to thermal energy.
What type of separation technique is used to separate ink into different colors?
Chromatography.
The separation depends on the solubility of each dye in the solvent used.
