Topic 1 & 2
What is the difference between a Pure Substance and Mixtures?
Pure substance = Have only 1 type of particle. They are all the same and blend chemically. (elements)
MIXTURES - have two or more pure substances in it. NO CHEMICAL change takes place.
How do we separate simple mixtures?
Filters!
Which way does Buoyant force push? Which force is it opposing?
Buoyant force is pushing upwards against gravity
True or False?
Gasses and liquids are compressible
False
who is the "Science Guy"
Bill Nye
What is the Solute, and what is the Solvent? Can you give an exmaple?
SOLUTE - the substance being dissolved (eg. Sugar)
SOLVENT - The substance doing the dissolving (eg. Water)
What is viscosity? Give an example of something with High and Low Viscosity?
Viscosity = The property that describes a fluid’s thinness or thickness
High Viscosity = Honey, Molasses,
Low = Water, Wine, Vinegar
What is Density referring to?
Place these in order of Least to Most Dense
Solid Gas Liquid
Density = How tightly Packed the particles in a substance are
Least: Gas, Water, Solid :Most
What are some ways humans have used the compressibility of gases to our advantage?
Air bags, shoe technology, crash pads, tires and wheels
Why is it easier to float in the dead sea?
Because the extra salt increases the density. So more dense items can float easier
How can we increase the speed of dissolving something?
name 3 out of the 4 ways
Agitation (shaking or stirring)
Break up the solute (make it smaller) so its dissolved easier
Add Heat
Increase Pressure
Sometimes we need more than filters to obtain different products. Can you explain how Fractional Distillation works?
Hot air (gases) rises
Difference in boiling point
Top of tower versus bottom
Condenses and collects
What do submarines and Aquatic fish use to control their buoyancy? (Sink and Rise)
Submarine = Balace Tanks
Fish = Swim Bladders
What is the relationship between Pressure and Area?
As you increase Area, pressure will decrease
As you decrease Area, Pressure will increase
Explain the mechanical flaw / error that occurred and the reason why the Titanic sank
The titanic did not completely seal the rooms / spaces. When it hit the iceberg and water started rushing in. Instead of just being isolated to one space, water was able to flow over and spread across the entire boat
What is a Colloid? Can you give examples?
Heterogeneous mixture that does not settle after stirring (but can still be separated). An emulsifying agent can be used to keep it an emulsion
ex = Mayo Peanut butter
What is Desalination of water? Explain how it works.
Desalination = removes impurities & minerals from salt and ocean water
How it works = Sea / ocean water is heated. From there the water turns into its gas form (steam / evaporation) and travels up a series of pipes. from there it cools, comes into contact with a copper pipe where the purified water is transported to its reservoir
How would you make something float in water if its overall density is higher?
Hint: Think of the Aluminum example
Change its shape
increase the area
add air pockets
What was the gas that used to be released from Aerosol cans
was it good or bad for the environment? why?
CFC - Chlorofluorohydrocarbon
Bad for the environment. It would pollute our ozone layer
Why do your ears pop when you are in a plane or diving deep in water
Airplane ear happens when there is an imbalance in the air pressure in your middle ear and the air pressure in the environment.
As you descend, water pressure builds on top of you. Ears popping is a body response
What's the difference between a Homogeneous Mixture and a Heterogeneous Mixture.
Give an example of each
Heterogeneous = (Mechanical Mixture) Two or more substances mixed together, but you can still see individual parts
ex - Greek salad, veggie oil & water, chocolate chip cookie
Homogeneous = (solutions) Things mixed so well together that it looks like one thing
ex - mouthwash, perfume, Kool-aid
How does Temperature effect Flow Rate for a gas and a liquid?
Liquid - increasing temperature will increase the flow rate: therefore, decreasing viscosity
Gas - Opposite! Increasing temperature will decrease the flow rate: therefore, increasing its viscosity
Explain the Eureka moment for Archimedes.
What was he asked to do
What was some of problems that arised
Answers may vary
Explain how Hydraulic Systems work
.
What are the steps to separating the valuable minerals from different ores?
Use gold as an example:
Blast and crush the ore
Mix the crushed ore with water to create a suspension
Add chemical to dissolve the gold
Filter
Add Zinc to release gold from solution
Gold residue sinks and is carried into a collecting tray