chem. unit test Flashcards
cation
positively charged ion
anion
negatively charged ion
ionic bond
simultaneously strong attraction of positive and negative ions in ionic compound
covalent bond
bond that results from the sharing of outer electrons between non-metal atoms
decomposition
1 substance breaks apart into 2 or more new substances
synthesis
2 or more substances combine to form 1 new product
endothermic
reaction is cooler than surroundings
exothermic
reaction is warmer than surroundings
physical change
when substance changes form but not chemical composition (paper cutting, ice melting)
chemical change
substance is altered at molecular level, creating a new chemical (bubbles/fizz, new colour, temp change, precipitate)
law of conservation of mass
in any given chemical reaction, the total mass of the reactants equals the total mass of the product
corrosion
the breakdown of a metal resulting from reactions with chemicals in its environment
galvanized steel
steel that bas been coated with a protective layer of zinc, which forms a hard, insoluble oxide
hydrogen test
- lowering burning splint into test tube
- splint pops
oxygen text
- lowering a glowing wooden splint into the test tube
- splint re-lights
carbon dioxide test
- add limewater into the test tube
- turns cloudy
hard or soft?
molecular - soft
ionic - hard
buffering capacity
the ability of a substance to resist changes in pH
phytoremediation
uses plants to clean up contaminated environments
pH scale
numerical scale ranging from 0-14 used to compare the acidity of solutions
acids contain
H
bases contain
OH
acid pH
0-6
base pH
8-14
