Which of the following has been test the LEAST and therefore is the LEASE reliable?
HOW MANY of the following four quanitites contain TWO significant figures, no more and no less?
24 miles per hour
10 decigrams per gram
In a graduated cylinder, if the meniscus of the liquid level rests JUST BARELY ABOVE the line for 5.3 mL, and the next line up is at 5.4 mL, which of the following options is the best way to record this volume?
If an atom that is originally uncharged GAINS three electons, it become _____ .
Given the following division probem: (6.626x10-34)/(9.63x108)=? What is the answer reported to the correct number of significant figures? (Assume both values are measured values.)
The study of matter that contains carbon is performed by a chemist in which branch of chemistry?
For which of the following choices do the two symbols describe atoms with the same number of protons?
B) 12C, 13C
A pure substance that CAN be broken down into simpler substances through some sort of typical chemical reaction is _____.
A) a compund
HOW MANY of the following seven elements are spedded correctly and are diatiomic elements?
B) 0 or 1
For which of the following choices are the numbers arranged correctly from smallest to largest?
A) (smallest) 2.11x10-3, 0.0023,3.04x10-2
How many electrons are in a 3s subshell that is only half filled?
How many sugnificant figures are in the value "0.02050 millimeters"?
HOW MANY of the following terms are associated with METAL elements
group 2A (orIIA)
3x103 m is the same as:
If an intern made an error and gave a patient a does of 275µg rather than 275mg of a drug, then:
B) the patient received an underdose by a factor of 1000
How many significant figures are in the answer to the following problem?
(Assume all values used in the calculation are measured quantities.)
HOW MANY of the following compunds have a name that ends with -ide? NaCN
Pure nitrogen in its natural form (at room temperature) exists as _____.
E) two atoms in a triple bond
In the compund Cr2O3, what is the charge on one of the Cr ions?
In the "sepatartions" experiment, how many of the following reasons could explain a % salt value that was LOWER than expected?
· Some salt was removed with the iron filings in the iron removal step
· The salt was not dissolved completely, so any undissolved salt would be in the filter paper with the sand
· The sand was not in the oven long enough to remove all of its water, giving the salt a lower overall mass percentage.
· Sputtering of dry salt caused loss of salt out of the beaker during heating.
· The salt was not in the oven long enough to remove all of its water giving the salt a lower overall mass percentage.
B) 4 or 5
The correct formula for the compund aluminum bisulfate is _______.
What is the electron configuation of the element scanduim (atomic number 21)?
a)1s22s23d104f3 b)1s22s22p63s23p64s3 c)1s22s22p63s23p64s23d1 d)1s22s22p63s23p63d3 e)1s21p61d101f3
What is the correct name of an ionic compound made only from sulfur and calcium?
C) calcium sulfide
Which of the following three dimensional molecules is polar?
D) CH2F2, where c is the only central atom
HOW MANY of the following comounds have FORMULA UNITS as their smallest units?
Which of the following groups of elements most likely form ANIONS when the become charged?
A centeral atom with BENT geometry has a bond angle about ____ degrees when they are ONLY THREE directions of electrons emanating from the centeral atom.
Which of the following atoms is least likely to form an ion?
HOW MANY of the following are isoelectronic with the electron configuration of the argon atom?
Ca2+ Al3+ P3- S2+ a) 0
Based strictly on periodic table position, which of the following has the highest electronegativity?
Which of the statements regarding the S-F bond is TRUE, if one of these atoms have 4.0 electronegativity while the other has 2.5 electronegativity? The S-F bond _____.
E) has a dipole pointing AWAY FROM the sulfur atom
The acidic component of stomach acid (or gastric juice) is ____.
a) hydrochloric acid
b) H2SO4 c) acetic acid
d)HNO3 e)phosphoric acid
a) hydrochloric acid
In a particular experiment to prepare a compound, the theoretical yield is 34.7g. If the actual yield is 31.2g, what is the percent yield?
Which of the following compounds is NOT an acid?
b) NaC2H3O2 c) HClO4 d) all of these are acids
e) none of these are acids
How many moles of H atoms are in 12.0 moles of CH4?
b) 6.02x1023 c)1.00
Which of the following is a correctly balanced equation of combustion reaction?
a) CaCO3--> CaO + CO2 b) 4Fe +3O2 --> 2Fe2O3 c) H2SO4 + 2NaOH --> 2H2O + Na2SO4 d) Ca2O2 --> Ca2 + O2 e) none of these
e) none of these
What occurs when the ionic compound NaNO3 dissolves in a lot of H2O to form a solution?
B) Na+ & NO3- ions are the solutes
A diprotic acid is a compound that
B) can donate up to 2 protons per molecule.
8.75 moles of ammonia contain how many ammonia molecules?
b) 6.02x1023 c)5.27x1024 d) 8.75x1023 e) cannot be determined
To balance the equation __C8H18 (g) + __O2 (g) --> __CO2(g) + __H2O(g) the correct coefficients in the blancks from left to right are:
MOLARITY is defined as the numner of
C) moles of solute per liter of total solution
What is mater?
Anything that has mass, and takes up space
What is chemistry?
The study of matter
What are the states of matter?
Solid, liquid, gas
What is physical change?
A change that does not alter the matter's chemical makeup.
What is chemical change?
a change that alters the matter's chemical makeup.
What is a diatomic molecule?
a molecule that contains two atoms
What is a triatomic molecule?
a molecule that contains three atoms
What is a polyatomic molecule?
an atom that has three or more atoms
what is a homoatomic molecule?
a molecule that contains atoms of only one element
What is a heteroatomic molecule?
a molecule that contains atoms from more than one element.
What is a pure substance?
a substance that contains only one component
What is an element?
a pure substance that cannot be broken into simpler forms by any chemican reaction
What is a compound?
a pure substance that can be broken down into two or more individual elements
What is a mixture?
a substance that contains two or more components,
what is a homogeneous mixture?
a mixture that is evenly distributed throughout
What is a heterogeneous mixture?
a mixture that is not evely distributed throughout
On the periodic table colums are calls___.
On the periodic table rows are called __.
Positive ions are ___.
negative ions are ___.
What is the "octet" rule?
the tendency for atoms to want 8 electrons in the valence shell
What is a chemical bond?
an attractive interaction between two atoms formed by a simple rearrangement of one or two calence electrons
What is a covalent bond?
formed when two atoms each share a valence electron with the other
Occurs between two nonmetal atoms
covalent bonds form molecules
What is an ionic bond?
formed when one atoms steals a valence electron from another
occurs when one atom is metal and the other is a nonmetal
ionic bond form formila unit
What is the VSEPR theory?
Valence shell electron pair repulsion.
According the this theory, valence electrons want to get as far away from each other as possible.
What is a polar covalent bond?
when one atom has a greater pull on the electrons of the bond
what is a nonpolar covalent bond?
when neither atom has greater pull on the elecrons of the bond.
Atoms with 1 to 3 valence electrons will tend to ____ electrons to get an octect
Atoms with 4 to 7 electrons will tend to ___ electons to get an octet.
What is the dipole moment?
The direction in which electrons of a polar covalent bond are pulled.
What is electronegativity?
the electron affinity of an atom while in a bond.
What is avogadros number?
What is theoretical yield?
the maximum number of grams of a product that can be produced based on the stoichiometry of a chemical reaction
What is experimental yield?
the actual number of grams of a product this is produced in a chemical reaction
What is percent yield?
# moles solute=
molarity x liters
What is arrhenius theory?
Arrhenius acid :substance that give up H+ ions
Arrhenius base: substance that give up OH- ions
What is wrong with Arrhenius theory?
it is to restrictive. Ammonia acts as a base, but doesn have OH- ions to give up.
Bronsted-lowry theory (acids)
Bronsted acid- substance that donates protons
monoprotic acid- can give up to one proton
diprotic acid- can give up to two protons
triprotic acid- can give up to three protons
Bronsted-lowry theory (base)
bronsted base subtance that accepts protons.
Explain the pH scale
pH 0 - is the most acidic, least basic
pH 7 - is neutral
pH 14- is the most basic, the least acidic.
Explain the pOH scale
pOH0 - most basic, least acidic
pOH14- most acidic, least basic.
The pOH scale works like the pH scale, but in the opposite direction.
What is buffer?
an aqueous solution containubg roughly equal concentraions of a weak acid and its conjugate base.
What is the job of a buffer?
not to neutralize pH but keep the pH from drastically changing.