Untitled Deck Flashcards
(46 cards)
qualitative v.s quantative observations
qualitative observation is and observation that can not be measured or expressed in numbers a quantatative obserbation is measurable and can be expressed in numbers
physical change
the substance involved remains the same substance, however, may change apearence of form. A physical change can be reversed by physical means.
chemical change/chemical reaction
the substsance is changed into one or more new substance that have different properties. Cannot be reverse by physical means.
infrence
a possible explanation of something you observe; or an educated guess based on your knowedhe, experience, and observation.
precipitate
a solid produced as the result of a reaction between two solutions.
exothermic reaction
a reaction in which heat is released.
endothermic reaction
a reaction in which heat is absorbed and the test tube or beaker will be noticbly cooler.
reactants
substances that are going to react with each other.
reactants make products
products
the substances that are made during a chemical reaction
reactants make products
Law of conservation of mass
During a reaction the way the atoms are joined is changed, however, atoms aren’t created or destryed so the mass of the products is equal to the mass of the reactants.
word equation
chemical name + chemical name arrow new chemical name
skeleton equation
a chemical equation written out with element symbols, arrows and + however aren’t balanced and don’t follow the law of conservation of mass.
how do you write a chemical equation
a balanced skeleton equation
how do you balance chemical equations
look at each individual element on both the reactants and products side and determine which atoms are unbalenced or balenced. If they are unbalenced add the appropiate coefecient in front. If the atom is a diatomic molecule if is alone it must contain a subscript.
aqueas
(aq) can be dissolved in water
synthesis
In a synthesis reaction, two elements or compounds combine to make one compound.
synthesis formula
a + b = c
decomposition
One reactant turns into two or more elements or compounds.
decomposition formula
a = b + c
combustion
a compound composed of only C, H, and sometimes O reacts with oxygen (02) if the combustion is complete the products will be CO2 and H2O
combustion formula
hydrocarbon + O2 turns into CO2 + H2O
single discplacement
One element replaces another. The reactans must be an element and a compount, and the product will be a new element and new compound.
single displacement formula
a + bc = ac + b
for a singe displacement reaction to occur …
the reacting metal must be more reactive than the metal that is being replaced in the compound. (refere to the acticity series of metsals)
