Chem Unit 2 Flashcards
Mass
Quantity of matter (number of atoms or molecules)
Weight
Measure of gravitational attraction
Pure substances
A material composed of only one type of particle
Ex: gold, oxygen
Pure substance single atom
Substance composed of only one type of atom; atoms are not bound to each other
Ex: copper, silver
Pure substance elements
Substance composed of only one type of atom, can be bonded together
Ex: diamond, graphite
Pure substance chemical compounds
Consists of atoms chemically combined together, have different properties than the individual elements themselves
Law of multiple proportions
Atoms can combine in multiple ratios, so long as while atoms are combined
Mixtures
A combination of pure substances, has unique chemical & physical properties themselves, and separated by physical means
Homogeneous mixtures
Composed of only one phase with a uniform distribution, so every part is identical
Heterogeneous mixtures
Non-uniform distribution of components, may have visibly different parts
Ex: chocolate chip cookies, muddy water
Solutions
Homogenous, has components mixed in a single phase, particles are small enough that they are not visible and do not settle out over time, transparent
Colloids
Heterogeneous, particles are still small enough that they cannot be seen and will not settle out over time
Suspensions
Heterogeneous, particles are large enough they can be seen and will settle over time
The Tyndall effect
Particles reflect light as it is coming through the mixture
Intensive vs extensive properties
Intensive- depend on the substance itself
Ex- color, density, solubility
Extensive- depend on the substance and how much you have
Ex- mass, volume, thermal energy
Signs of a chemical change
- temp change
- formation of a gas
- formation of a precipitate
- color change
- emission of light
Forms of energy
- potential energy
- kinetic energy
- thermal energy
- electrical energy
- sound energy
- radiant energy
Potential energy
Stored energy due to an objects position and current state
Conservation of energy
Energy is always conserved
Lost energy is usually converted to heat, sound
Exothermic vs endothermic reactions
Exothermic give off energy
Endothermic takes in energy
Energy transfer of temperature with different amounts
(Amount 1 X temp 1) + (amount2 X temp2)
Over amount 1 + amount 2
Methods of separating mixtures
- magnet
- density/decant
- filter
- chromatography
- evaporation
- distillation
- centrifuge
Decanting
Separates a mixture of solid and liquid or immiscible liquids, substances settle and separate by gravity from different densitys
Paper chromatography
A liquid mixture separates based on different properties of the individual liquids, father away the more similar
Centrifuge
Spins very rapidly in order to separate substances with different densities quicker
Exothermic phase changed
Freezing, condensation, deposition
