Chem Flashcards
Matter
Anything that has mass and takes up volume/space
Diffusion
The process of movement of particles from a high concentration area to a low concentration area to form an equilibrium
How does perfume liquid perform diffusion?
The liquid from the perfume spreads into the air, the liquid perfume has a higher concentration of particles than the air around and hence the particles move around until they reach equilibrium
2 factors affecting the rate of diffusion
Temperature - Higher temperature means higher kinetic energy, which makes the particles move faster and collide more frequently
Molecular Mass - Heavier molecules diffuse slower due to lower kinetic energy, while lighter molecules diffuse faster due to their lower molecular mass, Hydrogen gas (H2) has a molecular mass of 2 g/mol and diffuses faster than oxygen gas (O2) with a molecular mass of 32 g/mol.
solute
the substance which is being dissolved
Solvent
The liquid that is doing the dissolving (can sometimes be a gas as well)
concentration
Amount of particles in an area
Element
a chemical substance that cannot be broken down into other substances, composed of protons, neutrons and electrons, eg - Hydrogen
Mixture
Made of 2 or more substances that have been physically combined, can be separated using physical means, eg - soup
compound
two or more elements that have been chemically combined in a fixed ratio, eg - Water (H2O)
Pure substance
composed of a single element/compound and has a fixed and definite composition, eg - Iron
How to check if a substance is pure or not?
A pure substance has a constant and fixed melting point and boiling point, while an impure substance has a lower and broader melting point and a higher and broader boiling point
Homogenous mixture
Particles are distributed evenly and have a uniform composition
Heterogenous Mixture
Components are mixed and can easily be identified. Has a non-uniform composition
Element, mixture or compound - Zinc
Element
Element, mixture or compound - Saltwater
Mixture
Element, mixture or compound - Sugar Syrup
Mixture
Element, mixture or compound - Marble Chips
Compound
Element, mixture or compound - Aluminium
Element
States of Matter
Solid, Liquid and Gas
Properties of Solid
Particles are closely packed together and vibrate off each other, with definite shapes, High density and incompressible. Intermolecular space is less
Properties of liquid
Particles move freely, and medium kinetic energy, definite volume but no shape (takes the shape of a container), not compressible. Intermolecular space is more than solid but less than gas
Properties of gas
Particles roam around freely at high speeds, with no fixed volume and no fixed shape, compressible, low-density. Very high intermolecular space
Kinetic Theory of Matter
States that all matter is made of tiny particles (atoms) that are always moving
What are Heating and Cooling Curve
A simple line graph that shows the phase change a given substance undergoes with increase/decrease in temp
What are solutions
Homogenous mixtures which contain small solute particles in a solvent, eg - sugar in water
What are Suspensions
Heterogenous mixtures in which small particles of a solid remain suspended from a liquid/gas, eg - muddy water
What are colloids
Heteregrnous mixture made of 2 phases. The dispersed phase and the dispersion medium. They are mixtures where tiny particles are spread out but don’t settle, eg - milk powder and water mixture
Rank colloids, suspensions and solutions based on particle size (biggest to smallest)
- Suspensions
- Colloids
- Solutions
What are emulsions
Liquid + Liquid mixtures which are immiscible (not forming a homogeneous mixture when mixed) or are partly miscible, eg - Mayo, paint, egg yolks
What are the 6 main methods of separation of mixtures?
- Filtration
- Evaporation
- Simple Distillation
- Fractional Distillation
- crystallization
- chromatography
What is Chromatography
a technique for the separation of a mixture by passing it in solution in which the components move at different rates.
What is Paper Chromatography
The experiment uses to ink to see how it distributes on chromatographic paper
Does the solute travel more or the solvent, in chromatography
solute
Explain the stationary phase in chromatography
The stationary phase is that substance which does not move. Usually a solid but in paper chromatography, it can be a liquid as well
Explain the mobile phase in chromatography
The phase where the substance moves down the column and into the stationary phase.
What is Rf value?
is a ratio used to describe the distance a component in a mixture travels in relation to the distance the solvent travels
How to calculate Rf value
distance travelled by solute (stationary phase)/ Distance travelled by solvent
List some everyday uses of Chromatography
Forensic science
Creating Vaccines,
Food and Beverage Testing
Drug testing
What is Filtration
Used to separate solid from liquid. It is done with filter paper or a funnel
Eg - Getting chalk residue from chalk and water mixture
What is evaporation
Used to separate a solid from a solution it has been dissolved in. The solution is heated so that the liquid is evaporated and only the solid remains
What is Crystallization
separates solid from a solution by turning the mixture into crystals, then the crystals are left to dry. The remaining parts are the residue of the solid
What is simple distillation and what are its steps
Used to get the solvent from a solution
Steps:
1. Impure substance is heated
2. It boils and steam rises and condenses in condenser
3. Impurities are left behind
4. Steam condenses into the pure liquid and drops into the beaker
What is Fractional Distillation and what is its steps
Used to separate liquid from each other
Steps:
1 Mixture is heated
2. Wanted substance evaporates into the column
3. It then condenses in the beads in the column causing the beads to heat
4. When the beads reach a certain temp. (when the liquid stops condensing), wanted substance will heat and rise while the unwanted travels through the condenser and drops on the beaker.
Real-world uses of fractional distillation
purification of water
separating ethanol and water.
Separating crude oil into petroleum, diesel, etc.
