the safest technique for diluting a concentrated acid is to stir constantly while pouring the
acid into the water slowly
true or false: to safely light a bunsen burner, a student should adjust the burner to an open air valve and an open gas valve
true
what process involves a chemical change?
burning
what is an intensive property of matter?
density
one difference between a mixture and a compound is that
a compound can only be separated into its components by chemical means
at room temperature, a mixture of sand and water can be seperated by
filtration
expressed to the correct number of significant figures, what is the correct sum of (3.04g+4.134g+6.1g)?
13.3g
in a laboratory exercise to determine the density of a substance, a student found the mass of the substance to be 6.00 grams and the volume to be 2.0 milliliters. expressed to the correct number of significant figures, the density of the substance is
3.0g/ml
given: (52.6 cm)(1.214 cm). what is the product expressed to the correct number of significant figures?
63.9 cm^2
what is the quantity of 7896 millimeters expressed in meters
7.896m
what is the major advantage of the metric system over other systems of units?
is in multiples of 10
what quantity is represented by the metric system prefix deci-?
0.1
what is the metric system prefix for the quantity 0.000000
micro-
when 345.67 cm is added to 87 cm, the sum is correctly to _______ significant digits
3
the SI prefix for one millionth is
u
750.0 expressed in correct scientific notation is
7.599 x 10^2
an atom of an element contains 20 protons, 20 neutrons, and 20 electrons. this element is
an alkaline earth metal
the mass number of an atom is equal to the number of
neutrons plus protons
an experiment using alpha particles to bombard a thin sheet of gold foil indicated that most of the volume of the atoms in the foil is taken up by
empty space
when the electrons of an excited atom fall back to lower levels, there is an emission of energy that produces
spectral lines
the characteristic bright-line spectrum of an atom is produced when
electrons move from higher to lower energy levels
element x has two isotopes. if 72.0% of the element has an isotopic mass of 84.9 atomic mass units, and 28.0% of the element has an isotopic mass of 87.0 atomic mass units, the average atomic mass of element x is numerically equal to
(72.0
84.9)/(100)+(28.9
87.0)/100
what is the mass number of an atom that contains 19 protons, 19 electrons, and 20 neutrons
39
the elements of period 2 have the same
number of occupied principal energy levels
what is the maximum number of electrons that can occupy an orbital?
2
alkali metals, alkaline earth metals, and halogens are elements found respectively in groups
IA, IIA, and VIIA
in the modern periodic table, the elements are arranged in order of increasing
atomic number
given the electron configuration of an atom in the ground state: 1s^2 2s^2 2p^6 3s^2 3p^4....... this element is found in the periodic table in
period 3 and group 16
on the periodic table of the elements, all the elements within group VIA have the same number of
valence electrons
the number of valence electrons in an atom with an electron configuration of 1s^2 2s^2 2p^6 3s^2 3p^4 is
6
what is the highest principal quantum number assigned to an electron in an atom of zinc in the ground state
4
what is the wavelength of an electromagnetic wave that travels at 3 x 10^8 m/s and has a frequency of 60 Hz?
(300000000m/s)/(60Hz)
what is the approximate energy of a photon having a frequency of 4 x 10^7 Hz? (h=6.6x10^-34Js)
3x10^-26J
frequency of a photon having an energy 5x10^-24J (h=6.6x10^-34Js)
7x10^9Hz
compared to a proton, a neutron has
no charge and the same mass
the atomic mass of an element is the weighted average of the
atomic masses of the naturally occurring isotopes of that element
compared to the covalent atomic radius of a sodium atom, the covalent atom radius of a magnesium atom is smaller. the smaller radius is primarily a result of the magnesium atom having
a larger nuclear charge
as the elements Li to F in period 2 of the periodic table are considered in succession how do the relative electronegativity and the covalent radius of each successive element compare
the relative electronegativity increases, and the covalent radius decreases
the total number of completely filled orbitals in an atom of nitrogen in the ground state is
2
as the elements in period 3 are considered from left to right, they tend to
gain electrons more readily and increase in nonmetallic character
when an alpha particles is emitted by an atom, the atomic number of the atom will
decrease by 2
to determine the age of organic material, which mole ratio needs to be determined
14c to 12c
what is the total mass of 222Rn remaining in an original 160-milligram sample of 222Rn after 19.1 days
PLEASE JUST SHOOT ME NOW, I HATE CHEMISTRY SOO MUCH DDD:
a chemical bond between two atoms results from simultaneous
attraction by the two nuclei for the electrons
energy is released when the atoms of two elements bond to form a compound. compared to the total potential energy of the atoms before bonding, the total potential energy of the atoms after bonding is
lower and the compound formed is stable
the attraction which exists between carbon dioxide molecules in solid carbon dioxide is due to
van der waals forces
four single bonds of a carbon atom are directed in space toward the corners of a
regular tetrahedron
when a metal atom combines with a nonmetal atom, the nonmetal atom will
gain electrons and increase in size
the shape and bonding in a diatomic bromine molecule are best describes as
symmetrical and nonpolar
a substance was found to be a soft, nonconducting solid at room temperature. the substance is most likely
a molecular solid
metallic bonding occurs between atoms of
copper
hydrogen bonding is strongest between molecules of
H2O
oxygen, nitrogen, and fluorine bond with hydrogen to form molecules. these molecules are attracted to each other by
hydrogen bonds
what type of bonding is found in all molecular substances
covalent bonding
compound contains both ionic and covalent bonds
CaCO3
what is the chemical formula for nickel (II) hypochlorite
Ni(ClO)2
name of the compound whose formula is N2O5
nitrogen (V) oxide
what is the correct name for the compound with the formula CrPO4
chromium (III) phosphate