Mix and Flow of Matter
Topic 1: Mixing Matter
The main points of the Particle Model of Matter
What is the difference between pure substances, mixtures, and solutions?
Pure Subtances: A class of matter made up of only one substance (eg., water, salt).
Mechanical Mixture: A class of matter that is made up of multiple substances, the molecules don't fully mix. You can often see the different parts (eg., fruit salad) Also referred to as Heterogeneous Mixture, which means the different parts are visible and clear.
Solutions: A class of matter made up of multiple substances that are fully mixed, you cannot tell the difference between parts. (eg., apple juice) Also referred to as Homogeneous Mixtures. The mixture looks the same throughout.
Classification Key
Suspension: A suspension is a heterogeneous mixture where small particles particles are added to the fluid, Suspensions won't dissolve.
Colloid: A mixture where the pieces are so small, you can hardly tell, but they are not fully dissolved. In between a suspension and a solution. (eg., milk)
Solutions
What is a Solution? A mixture of multiple substances where the particles are fully mixed with eachother, Solutions look like one substance, and it is difficult to seperate the parts.
Solutions are made up of a solvent and a solute. Solutes are substances dissolved in the solvent. Solvents aren't always water.
What is dissolving? A process where a solute's particles completely mix with a solvent. When a solute is able to dissolve, it means it's soluble.
The process of dissolving can be explained using the PMOM. When the particles in a solute are more attracted to the solvent than they are to eachother, the solute's particles are pulled apart.
Concentration
One of the properties of a solution is it's concentration. Concentration describes the amount of a solute compared to the amount of a solvent.
Unsaturated: More solute can stil be dissolved, not fully dissolved yet.
Saturated: All the solute that can be has been dissolved.
Supersaturated: The solvent has been affected in a way that it's able to dissolve more solute than it could usually.
Concentration = solute (g) / solvent (mL)
Increasing the Rate of Dissolving
Topic 2: Properties of Fluids
Viscosity is a physical description of a fluid's resistance to flow. Viscosity = Thickness. Thicker fluids are more viscous.
Flow rate is a measurement of how easily a fluid flows. We can measure this by speed or distance.
When a liquid heats up, it's molecules start to move faster. This increases the flow rate, and makes things less viscous.
Compressibility is the measure of how much a volume of matter decreases when placed under pressure. Squished.
The volume of solids cannot be changed. Solids cannot be compressed.
Dilution is making a liquid thinner/less dense.
Liquids cannot be easily compressed because they have a definite volume.
Gases don't have a definite volume or shape, we can compress it easily.
How are density and buoyancy connected?
Mass: The amount of matter in a substance. (kg)
Volume: the measurement of the amount of space occupied by the substance.
What is density? Density is the mass per unit volume of an object.
Density = Mass / Volume
The density of water is equal to 1g/cm³ If the density of an object is less than 1, it will float. If the density is more than 1, it will sink.
Pressure
Pascal's Law states that when pressure is applied to an enclosed liquid, the pressure and force is transmitted equally throughout the liquid in all directions.
Buoyancy is the tendency of an object to float when placed in a fluid. When an object is in a liquid, the force of gravity pulls it down, the liquid however exerts an opposite force that pushes the object upward. This is called the buoyant force!
Buoyant Force: An upward force, opposite to the pull of gravity on an object in a fluid.