Chapter 1 - Chemistry and Measurement Flashcards
What is Chemistry?
the central science, everything depends on it
Give some examples of what chemistry has provided for us in the world
- better crop yields
- more nutritious food
-fuels - better health (medications)
What 3 phases does matter exist in?
Solid, liquid, gas
What are pure substances?
they have a fixed composition and have unique properties that can be used to identify a substance
ex: elements and compounds
What is a mixture?
composed of 2 or more pure substances in which each substance maintains its identity and they can be separated into their components
What is a homogenous mixture?
“solution” in which the composition is the same throughout
- if you split it into two bottles/pieces, the two pieces/bottles would have the same components
What is a solution
a solute dissolved into a solvent
What is the solute?
the substance being dissolved
ex: salt or sugar
What is the solvent?
the dissolving medium
ex: water (H20)
Give an example of a homogenous mixture
coffee, metal alloys (Brass, Bronze)
What is a heterogenous mixture?
mixture that is non uniform in appearance in which its composition varies throughout
ex: a rock, choc chip cookie, salad
What is filtration as a method of separating mixtures?
passing a mixture through fine pores to separate solid from a liquid
What is distillation as a method of separating mixtures?
separation of homogenous mixtures by boiling points (heat it up until one substance’s boiling point is hit)
What is chromatography as a method of separating mixtures?
separating a mixture by color (paper chromatography)
What are extensive properties?
dependent on the amount of the substance and cannot be used to identify a substance
ex: mass, volume
What are intensive properties?
independent of the amount of the substance and can be used to identify a substance
ex: boiling point, specific heat, density
What are physical properties?
properties than can be measured w/o changing the identity of the substance
ex: color, boiling point
What is density?
mass/volume, an intensive property made up of 2 extensive properties
ex: the difference between cake and cheesecake
What is solubility?
how much of a substance will dissolve in a specific amount of solvent at a specific temp
ex: KNO3 -> 32g/100g H20 @ 20 degrees C
Absorbance and Transmittance
a substance has a specific color due to its absorbance and transmittance of light
- the color is what is transmitted because it was not absorbed
What are chemical properties?
properties that can be determined only by changing the identity and composition of the substance
- destructive test is needed
ex: Flammability
nano- (n)
10^-9
pico- (p)
10^-12
What are the 2 things that accuracy is dependent upon?
- The measuring device
- The skill of the operator
