Chapter 2 And 1.3 Flashcards
(28 cards)
Element vs. compound
Element: substance made form ONLY one type of atom
Compounds: substances made form 2 or more types o atoms
Pure substance vs. mixture
Pure substance: all particles are the same and no & defined an constant
Mixture: different particle types
A combination of pure substances
Physical properties vs. chemical properties
Physical: can be observed without changing identity of substance
Chemical: can only be observed when substances react with something else
Physical change vs. chemical change
Physical: a change in appearance, but no change in composition
Chemical: a new substance is formed
Extensive vs. intensive properties
Extensive: depends on substance amount ( mass and volume)
Intensive: does not depend on amount of substance. (Color, smell)
Solids vs. liquids vs. gases
Solid: independent shape, tight particles, has shape and volume.
Liquid: close particles, not independent shape
Gas: fills volume (expands), far apart particles
Reactants vs. products
Reactant: chronicles present at start of reaction
Product: chronicles produced in reaction
Exothermic vs. endothermic reactions
Exothermic: give off heat
Endothermic: absorbed heat
Four indications of chemical reaction
- Transfer in energy (heat/light)
- Change in color
- Production of gas
- Formation of precipitate
Defiance precipitate
A solid that forms and settles on the bottom of an aqueous solution
What does the law of conservation of mass state
In a physical and chemical change always stays the SAME
Product weight= reactant weight
Reversible vs. irreversible change
Reversible: melting and freezing
Irreversible: tearing paper
Matter
Everything with mass and volumes
What is the difference between an Observation and an Inference
Observation- information gathered using the 5 senses and measurement
Inference- conclusion based on the observations and past knowledge
Define chemistry
The study of matter and it’s changes
Lab safety
Freakin common sense
Measuring to the correct decimal
Measure to what you can and guess once
Define an atom
Atom is smallest particle of an element that retains its identity in a chemical reaction
View of an atom changes overtime
- Democritus
Thought atoms were solid spheres (smallest they get) - Dalton
Tough matter consisted of small lumps (atoms) - Thomson
Plumb pudding model (discovered electron and thought it would also have something positively charged) - Goldstein
He discovers the nucleus
5. Ruthoford
Electron cloud through tin foil experiment.
6. Bohr
Electron orbitals
7. Chadwick
Discovered the neutron
Compare and contrast subatomic particles (electron, proton, neutrons)
Electron e- -1 charge 1/1849 mass 9.11x10 to the -28th mass
Proton p+ +1 charge 1 mass 1.67x10 to the -24th mass
Neutron n0 0 charge. 1 mass 1.67x10 to the -24th mass
Interpret a nuclear symbol
Mass # is the top left
Atomic # is the bottom left
Charge is the top right
Mass - atomic number = neutrons
Isotope
Atoms with different number of neutrons
Define average atomic mass and how to calculate it
It’s the weight average of all the naturally occurring isotopes in that element. Found on periodic table below element symbol.
Describe how the Bohr of an atom improved upon earlier models.
It specified that electrons ain’t in electron clouds but in specific paths (orbits) around the nucleus. The highest energy
Level is furthest from the nucleus.
