The Core of Chemistry 96 pg guide Flashcards
What is a theory?
An explanantion of some event or phenomenon that is well supported by data.
- not facts
- ‘may change with discovery of information
- tested over and over with same results
- why something occurs
- predict results of future observations
What is a law?
A description of a natural event or phenomenon shown to occur again and again under the same conditions. A scientific law describes the observed pattern without trying to explain it.
- accepted as true and universal
- well supported by observations, experimentation, and data
- can be challenged and possibly disproven although it is very rare
Accuracy
Refers to how close a measured value is to the true measurement (true value) of something
Precision
Refers to the ability to take the same measurement and get the same result over and over.
Weight
A measure of the pull of gravity between an object and the earth.
It is actually a measure of force
weight= mass x gravity
Weight on other planets based on 100 pounds
- Mercury- 38
- Venus- 88
- Earth- 100
- Mars-38
- Jupiter- 235
- Saturn-105
- Uranus- 89
- Netune- 120
Density
The amount of matter per unit of volume
- density= mass/ volume
Convert oC to K
oC + 273.15= K
Convert oF to oC
F= (1.8 x (C)) + 32
Convert oC to oF
C= F - 32
1.8
What is pressure? What is the formula?
The amount of force exerted on an area.
pressure= force/area
Force
The amount of push or pull on an object.
What are the two types of matter? Name their subcategories?
- Pure Substance
- Compounds
- Elements
- Mixture
- Homogeneous (soda pop, brass)
- Heterogeneous (pizza, salad)
What are the properties of matter?
- Physical properties
- Chemical properties
Define: Physical Properties of Matter
A property of matter that can be observed without changing the substance into another substance.
E.g. density, color, boiling point, and melting point.
Define: Chemical Properties of Matter?
Determined by the ability of a substance to react with or change into another substance.
What is toxity?
The potencial of a substance to have a harmful effect on an organism. It is a chemical property because you can only determine toxicity by observing how a substance reacts with another substance.
Can vitamins be toxic?
Yes, in extremely large quantities.
Is toxicity related to the amount of a substance?
Yes
Which word correctly expresses that something is not flammable: Inflammable or Nonflammable?
Nonflammable.
Inflammable is actually a synonym for flammable.
What is the fire triangle? What are it’s conditions?
The fire triangle is made uo cerain conditions that are needed for a fire to occur.
- Fluel
- Oxygen
- Energy
Define: Crystalline solids or Crystalline structure
A solid made up of atoms or molecules that are organized in specific repeated patterns. (e.g. quartz, cotton candy)
Define: Amorphous solids
Solids made up of atoms or molecules that are locked into place. However, those atoms or molecules do not organize into a specific form or neat, repeating structure. (e.g. glass, wax, rubber)
What is Viscosity?
A property of liquids that describes the “thickness” of the material. It is a measure of the liquid’s resistance to flow. The less viscous a liquid is (the lower its viscosity), the more easily it flows.
What is surface tension?
A property of liquids that describes the attraction of liquid molecules at the surface. (It brings the molecules closer together at the surface.) The stronger attraction of molecules at the surface of the liquid creates a surface “film.” This film makes moving an object through the surface of a liquid more difficult than moving the object when it is completely submerged in the liquid.
Define: Effusion
The process by which gas particles flow through small holes in a container. This is why a baloon filled with helium gas will deflate over time.
Define: Molecular Mass
The mass of one molecule of a substance
What effect does molecular mass have on effusion?
Gases with a lower molecular mass effuse more quickly than gases with a higher molecular mass.