CHEM 1030 Exam 3 – Forbes Questions With
Correct Answers
Law of Conservation of Mass - CORRECT ANSWER✔✔-matter cannot be created
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or destroyed and therefore mass is always conserved in a chemical reaction
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stoichiometric coefficient - CORRECT ANSWER✔✔-tells us the ratio of each
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element in a chemical equation - based on moles
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What reacts in a chemical equation? - CORRECT ANSWER✔✔-MOLES REACT
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WITH MOLES - grams do not react with grams
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deriving empirical formulas from percent composition - CORRECT ANSWER✔✔-1.
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assume you have 100 g of sample
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2. convert percentages to mass values
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3. convert mass to moles
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4. calculate a mole ratio by dividing by the smaller mole value
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5. convert mole ratio to small whole numbers
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percent composition - CORRECT ANSWER✔✔-the percentage by mass of the
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constituent elements of a compound with respect to its total mass
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finding percent composition - CORRECT ANSWER✔✔-% comp.= [(mass of
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element)/(total mass)] x 100 | | |
, relationship between molecular and empirical formula - CORRECT ANSWER✔✔-
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molecular formula = (empirical formula)n | | | |
how to find n in reference to deriving molecular formula - CORRECT ANSWER✔✔-
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n = molecular mass / mass of 1 empirical formula unit
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combination reaction - CORRECT ANSWER✔✔-two or more reactants combine to
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form a new larger product
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decomposition reaction - CORRECT ANSWER✔✔-a single reactant breaks down to
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form 2 or more products
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single displacement reaction - CORRECT ANSWER✔✔-a single element displaces a
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similar element in another compound
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double displacement reaction - CORRECT ANSWER✔✔-two elements are
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displaced (like switching partners) - similar things replace similar things
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combustion reaction - CORRECT ANSWER✔✔-a rapid reaction between a
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molecule/compound and oxygen that produces energy (heat) | | | | | |
hydrocarbon combustion - CORRECT ANSWER✔✔-when a hydrocarbon reacts
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with oxygen to form carbon dioxide and water
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CH + O2 -> CO2 + H2O + heat
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Correct Answers
Law of Conservation of Mass - CORRECT ANSWER✔✔-matter cannot be created
| | | | | | | | | | |
or destroyed and therefore mass is always conserved in a chemical reaction
| | | | | | | | | | |
stoichiometric coefficient - CORRECT ANSWER✔✔-tells us the ratio of each
| | | | | | | | | |
element in a chemical equation - based on moles
| | | | | | | |
What reacts in a chemical equation? - CORRECT ANSWER✔✔-MOLES REACT
| | | | | | | | | |
WITH MOLES - grams do not react with grams
| | | | | | | |
deriving empirical formulas from percent composition - CORRECT ANSWER✔✔-1.
| | | | | | | | |
assume you have 100 g of sample
| | | | | |
2. convert percentages to mass values
| | | | |
3. convert mass to moles
| | | |
4. calculate a mole ratio by dividing by the smaller mole value
| | | | | | | | | | |
5. convert mole ratio to small whole numbers
| | | | | | |
percent composition - CORRECT ANSWER✔✔-the percentage by mass of the
| | | | | | | | | |
constituent elements of a compound with respect to its total mass
| | | | | | | | | |
finding percent composition - CORRECT ANSWER✔✔-% comp.= [(mass of
| | | | | | | | |
element)/(total mass)] x 100 | | |
, relationship between molecular and empirical formula - CORRECT ANSWER✔✔-
| | | | | | | |
molecular formula = (empirical formula)n | | | |
how to find n in reference to deriving molecular formula - CORRECT ANSWER✔✔-
| | | | | | | | | | | |
n = molecular mass / mass of 1 empirical formula unit
| | | | | | | | | |
combination reaction - CORRECT ANSWER✔✔-two or more reactants combine to
| | | | | | | | | |
form a new larger product
| | | |
decomposition reaction - CORRECT ANSWER✔✔-a single reactant breaks down to
| | | | | | | | |
form 2 or more products
| | | | |
single displacement reaction - CORRECT ANSWER✔✔-a single element displaces a
| | | | | | | | |
similar element in another compound
| | | | |
double displacement reaction - CORRECT ANSWER✔✔-two elements are
| | | | | | | |
displaced (like switching partners) - similar things replace similar things
| | | | | | | | |
combustion reaction - CORRECT ANSWER✔✔-a rapid reaction between a
| | | | | | | | |
molecule/compound and oxygen that produces energy (heat) | | | | | |
hydrocarbon combustion - CORRECT ANSWER✔✔-when a hydrocarbon reacts
| | | | | | | |
with oxygen to form carbon dioxide and water
| | | | | | |
CH + O2 -> CO2 + H2O + heat
| | | | | | | |
