Physical Science test 3
What kind(s) of bonding takes place in NaOH?
both covalent and ionic
What is the number of oxygen atoms in Al2(SO4)3?
12
What is the total number of atoms in calcium phosphate, Ca3(PO4)2?
13
What is the formula weight of methane, CH4?
16 u
What is the mass percent of sodium in washing soda, Na2CO3?
43.4%
The maximum number of electrons that can have the principal quantum number 2 in a given atom is
8
What is the total mass of products in the methane reaction shown before question 11? CH4 + 2O2 → CO2 + 2H2O
80 u
What is the number of atoms on each side of the equation? CH4 + 2O2 → CO2 + 2H2O
9
What is the empirical formula of C4H8?
CH2
A decomposition reaction always breaks down a compound into the elements that make up the compound.
False
An atom becomes a positive ion by gaining an electron.
False
Atoms gain or lose electrons in chemical reactions in order to increase their energy state.
False
Elements in the same row of the periodic table exhibit similar chemical properties.
False
In combination reactions, elements react to form compounds.
False
Ionic bonds occur between atoms from adjacent groups.
False
Substances that lose electrons in reactions are called oxidizing agents.
False
The -ide ending in nitrogen dioxide tells you that this is an ionic compound.
False
The atomic number of an element is the total number of protons and neutrons in the nucleus.
False
The empirical formula gives the actual number of atoms of each kind in a compound.
False
The sum of the coefficients must be the same on both sides of a chemical equation.
False
When balancing a chemical equation, you need to change subscripts to make the number of atoms of an element the same on both sides of the equation.
False
The element M forms a stable ionic compound MCl2. If M were allowed to react with bromine, the resulting compound would have the formula
MBr2.
Atoms from an element in group VA are allowed to react with atoms from an element in group VIIIA. What type of compound is likely to form?
None of the above. ionic covalent polar
A covalent bond is a shared pair of electrons.
True
An electron moves from one orbital to another only when it absorbs or emits energy.
True
Atoms gain or lose electrons in order to attain a valence orbital arrangement like that of a noble gas.
True
Chemists effectively count atoms by weighing matter.
True
In a chemical equation, the reactants are found on the left side of the arrow.
True
J.J. Thomson discovered that cathode rays were really a stream of electrons.
True
Protons and neutrons have about the same mass.
True
Protons are so much more massive than electrons that you can neglect the mass of electrons when determining the mass of an atom.
True
The breaking and making of chemical bonds can explain chemical reactions and energy flow.
True
The representative elements have one to eight valence electrons.
True
The word halogen comes from the Greek, meaning salt-former.
True
When balancing a chemical equation, the number of H atoms in 2 CH4 is eight.
True
When compounds containing carbon and hydrogen are burned in air, the products are usually carbon dioxide and water.
True
Evidence of a chemical reaction includes
a color change. a change in temperature. the production of a gas. All of the above.
J. J. Thomson reasoned that cathode rays were really charged particles because
a magnet deflected cathode rays.
Which of the following is a sign of an ion exchange reaction?
a precipitate is formed.
When atoms of non-metallic elements react with one another, they tend to seek stability by
acquiring a noble gas electron arrangement.
Atoms that have eight valence electrons would tend to
be inert.
What is the correct name for the ionic compound, CaF2?
calcium fluoride
A chemical reaction is balanced by changing (the)
coefficients.
What type of chemical bond does the sharing of a pair of electrons form?
covalent
John Dalton reasoned that atoms exist from the evidence that
elements always combined in certain fixed ratios.
Atoms in an incandescent gas
emit characteristic frequencies of light.
The amount of energy released when wood is burned is
equal to the amount of solar energy that was stored by the plant.
The formation of an ionic bond
involves a transfer of one or more electrons. results in a release of energy. helps atoms achieve a noble gas electron arrangement. All of the above.
The reaction between water solutions of sodium chloride and silver nitrate produces a precipitate: NaCl(aq) + AgNO3(aq) → NaNO3(aq) + AgCl(s). This is an example of
ion exchange
Atoms from an element in group IIA are allowed to react with atoms from an element in group VIIA. What type of compound is likely to form?
ionic
In an ionic compound, the metal
is written first.
Which combination of elements results in the formation of a white crystalline solid that dissolves to form a solution that conducts electricity?
metal and non-metal
The smallest unit of a covalent compound that still retains the properties of the compound is called a(an)
molecule.
Neutral atoms of a given element all have the same
number of protons. atomic number. number of electrons. All of the above.
The formation of a positive ion
occurs when an electron is removed from an atom.
According to the quantum mechanical model, electrons exist in
orbitals.
The reaction 2 Mg + O2 → 2 MgO is an example of
oxidation. combination. combustion. All of the above.
A chemical bond that involves somewhat unequal sharing of electrons is called
polar.
The atomic number of an element is the number of
protons.
An oxidizing agent is a substance that
removes electrons from another substance.
The reaction: 2 NaI + Cl2 → 2 NaCl + I2 is an example of
replacement.
Robert Millikan discovered that
the electron carries the smallest unit of electrical charge.
Because of our belief in the law of conservation of mass, it seems reasonable that
the number of atoms of reactants must equal the number of atoms of products.
When Rutherford found that some of the alpha particles fired at the gold foil were widely deflected, he concluded that
the positive charge in an atom is concentrated in a tiny nucleus.
Isotopes of an element are atoms that have
the same number of protons, but a different number of neutrons.
Ionic compounds are generally
white, crystalline solids.
