# Chem exam 1 review

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2017-10-18 21:31

## Chap 3

Question | Answer |
---|---|

How to find average atomic mass of an element | f1M1 + f2M2 +… + fnMn where f is the fraction representing the natural abundance of the isotope and M is the mass number (weight) of the isotope. |

What is Avogadro's number and what does it represent | 6.0221367x10^23 and it represents a mole |

How many grams of Li is one mole of Li atoms | 6.941 (same as atomic mass) |

for any element, what is molar mass also equal to | atomic mass (amu) |

what are the units for molar mass | grams |

how to go from grams to amu | multiply by 6.022x10^23 |

how to go from amu to grams | multiply by 1.66x10^-24 |

how to calculate number of atoms of an element | number of moles multiplied by avogadro's number |

how to calculate number of moles of an element | mass of element divided by molar mass in g/mol |

what is molar mass also known as | molecular weight |

unit for molar mass | g/mol |

how to find molar mass of a compound | find atomic mass of each element and then multiply that by each element's subscript and then add the results together |

when are zeros significant | after a number on the right of the decimal or between numbers |

when multiplying exponents how do u decide how many significant digits to put in the answer | look at how many significant digits the factor with with exponent and also the most significant digit has |

what is um | micrometeres |

go over hw assignments | ok |

what is formula for density(p) | mass/volume |

how many in to cm | x 2.54 |

mi to km | x 1.61 |

hr to sec | 3600 |

km to mi | divide by 1.61 |

m to ft | x 3.28 |

cubic m to l | x 1000 |

cubic meters to cubic inch | x 61023.7 |

l to cubic inch | x 61.0237 |

cubic m to l | x 1000 |

gal to l | x 3.78541 |

name for LiH | Lithium hydride |

name for AlI3 | Aluminum Iodide |

## chap 1

Question | Answer |
---|---|

how many elements, how many natural, how many man made | 118, 82, 36 |

extensive properties | as opposed to intensive properties depend on how much material is there |

example of microscopic measurement | mole |

SI unit for temperature | Kelvin |

celsius to kelvin | PLUS 273.15 |

celsius to fahrenheit | x1.8 then plus 32 |

fahrenheit to celcsus | minus 32 then divide by 1.8 |

pico | 10^-12 |

tera | 10^12 |

(for si exponents for tera giga mega kilo deci centi milli micro nano pico) it go | (by 3's): 12 9 6 3 now negative 1 2 3 6 9 12 |

weight equals what on earth and what on the moon | mass on earth, mass times .1 on moon |

SI unit for volume | cubic metre |

cubic metres to litres | x 1000 |

how many milliliters is one cubic centimeter | 1 |

SI unit for volume | kg/m^3 |

how many atoms are in 12 grams of carbon | 6.022x10^23 |

amu to mole | atoms/6.022x10^23 |

## chap 2

Question | Answer |
---|---|

atomic theory by who of when is what | by Democritus 5th century to Dalton 1808 is belief everything is made up of atoms |

who's theory is law of definite proportions supported by and what is it | its in dalton of 1808's atomic theory it says elements' proportions of atoms are either integers or simple fractions |

laws that support dalton's atomic theory of 1808 | law of conservation of mass ( in chemical reactions), law of definite proportions ( of a compounds), law of multiple proportions (between compounds) |

amu to g | x 1.66x10^-24 |

how to calculate molecular weight nd what is unit | for each element in the compound find the atomic mass and multiply that by how many of that element there is in the compound then add the result with that of the other elements in the compund and thats the molecular weight in g/mol |

how to go from g to mol | g/molecular weight |

explain law of multiple proportions | when two elements combine with each other to form more than one compound, the weights of one element that combine with a fixed weight of the other are in a ratio of small whole numbers |

## chap 4

Question | Answer |
---|---|

define a solution | a homogenous mixture of two or more substances |

what is an aqueous solution | a solution in which the solvent is water and the solute is initially liquid or solid |

difference between electrolyte and nonelectrolyte | electrolyte when dissolves in water makes a solution that can conduct electricity |

difference between strong and weak electrolyte | strong electrolyte dissociates 100% but a weak electrolyte does not completely dissociate |

what is Ionization | losing or gaining electrons to become positively or negatively charged thus forming an ion |

hydration definition | the process in which an ion is surrounded by water molecules arranged in a specific manner. |

What property of water enables its molecules to interact with ions in solution | water is a polarized compound and can hydrate both positive and negative ions |

a reaction that is an example of metathesis reaction | precipitate reaction |

another name for metathesis reaction | double displacement reaction |

what is precipitate reaction | results in formation of an insoluble compound aka precipitate |

what does metathesis reaction involve | the exchange of parts between two compounds |

what property of a solution determines whether a precipitate forms | solubility |

what is solubility | the maximum amount of a solute that will dissolve at a certain temp |

look at | slide 16 of chap 4, memorize insoluble and exceptions |

formula for ammonium | NH4+ |

ions that do not change in a reaction | spectator ions |

ionic equation vs molecular equation | ionic shows ions for each, molecular shows molecule version of the equation |

net ionic equation | does not show spectator ions |

steps to write net ionic equations | balance equation, identify precipitates, shows dissociation, cancel spectator ions, balance charges w/ ions |

what do acids produce after reacting w/ certain metals | hydrogen gas |

what is produced when acids react w/ carbonates and bicarbonates | carbon dioxide gas' |

what type of acid and base solutions conduct electricity | aqueous |

how do bases feel | slippery |

what type of acids and bases are proton donors and acceptors respectively | bronsted |

what is a neutralization reaction and what does it produce | it is a reaction between acid and base and produces water and salt |

what is oxidation reduction reaction | electron transfer reaction |

what is the oxidation number of free elements in an uncombined state | zero |

what is the oxidation number of a monatomic ion | the same as the charge |

O usually has an oxidation number of -2 but what is the oxidation number for O2 | -1 |

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