CHM265 Ch.1 Reading Questions
cradle-to-grave
An approach to analyzing the life cycle of an item, beginning with the raw materials from which it is made to its ultimate disposal, is called the _____ approach.
cradle-to-cradle
An approach to consumer goods that aims at recycling, so that the end of the life cycle of one item leads naturally into the beginning of the life cycle of another, is the ___ approach.
17, 19
An atom of chlorine (Cl) has a mass number of 36. This atom has ___ protons and ___ neutrons in its nucleus.
ions electrons
An electric current is the net movement of _____.
insulator
Does not allow the flow of electricity
Element= one atom Compound=two atoms of different elements bonded together
Element= Compound=
conductor
Enables the flow of electricity
noble gases
Generally unreactive
metal
Good conductor of heat and electricity
alkali metals
Make soil and water alkaline
chemical compounds found in rocks and soil
Minerals are _____.
The proportions of the components can vary The components can be separated by physical means
Mixtures...
There are 14.0 g of nitrogen in every 46.0 g of NO2 The percentage of oxygen in NO2 is equal to 32.0/46.0 x 100% The percentage of nitrogen in NO2 is equal to 30.4%
Molar mass of NO2=46.0 g/mol; molar mass of nitrogen=14.0 g/mol; molar mass of oxygen=16.0 g/mol.
electron
Negatively charged particles
mixture
Physical combination of two or more species
nonmetal
Poor conductor of heat and electricity
Quartz
Pure crystallized SiO2 with a highly ordered arrangement at the atomic level
Glass
Random array of silicon and oxygen linkages throughout the solid
alkaline earth metals
Result in hard water
10
Scientific notation expresses a quantity with a single digit before the decimal point and followed by ____ raised to the appropriate power.
F,T,T,F
T/F The chemical symbol for iron is I T/F The chemical symbol for argon is Ar T/F The chemical symbol for carbon is C T/F The chemical symbol for cobalt is CO
mass, neutrons
The ____ number of an atom is equal to the total number of protons and ___ in the nucleus of the atom.
least
The accuracy of a calculation is limited by the quantity that has the _____ number of significant figures.
Is equal to the number of protons in the nucleus Each element has its own unique atomic number
The atomic number of an element...
mole
The molar mass of any substance is the mass of 1 ___ of the particles of that substance.
contains the chemical symbols that represent the elements the elements in the periodic table are arranged based on similar chemical properties
The periodic table...
The sum of the oxidation numbers for the atoms in a neutral compound is zero The ON for a monatomic ion is the same as its charge
The rules for assigning oxidation numbers (ON):
mass, charge
To balance a half-reaction, the number and type of each element present is balanced to reflect the conservation of _____ in the reaction. Electrons are added to the appropriate side of the equation to reflect the conservation of _____.
20 nm x 1 x 10^-9 __________ 1 nm
To convert from 20nm to m, given that 1nm=1 x 10^-9 m, set up the equation as:
+4
What is the oxidation number of S in SO2?
+2
What is the oxidation number of iron in FeO?
the number of atoms of a particular element is indicated by a subscript A chemical formula is a symbolic way to represent the composition of a substance
When writing the chemical formula of a substance...
Hydrogen, Oxygen, Nitrogen, and Fluorine
Which element commonly occurs as a diatomic molecule?
O2 O3
Which of the following are allotropes of oxygen?
pure substance
form of matter with a definite composition
reduction
gain of electrons
oxidation
loss of electrons
proton
positively charged particle found within the center of the atom
neutron
uncharged dense particle located in the center of the atom
significant
A ___ figure is a digit that represents the accuracy with which an experimental quantity is known.
molecule
A ______ is independent structure consisting of two or more atoms chemically bonded together
formula
A chemical ____ (CO2) represents the elementary composition of any pure substance.
equivalent, 1
A conversion factor is ratio of _____ quantities used to express a quantity in different units of measurement. Multiplying by a conversion factor is the same as multiplying a quantity by ____ because the numerator and denominator are equivalent.
are extremely small compounds contain two or more different types of atoms An atom is the smallest unit of an element that can exist as a stable, independent entity
Atoms...
mass, space
Chemistry is the study of matter, which is commonly defined as anything that has ____ and occupies ______.
mole
Chemists use the ___ as a unit of amount of substance.
air=mixture O2= pure substance
Classify air and oxygen (O2) as mixture or pure substance
Covalent compound=CO2, N2O5, PCl3 ionic compound=NaBr, FeCl3, NiO
Classify each compound as either covalent or ionic compound: NaBr, CO2, FeCl3, NiO, N2O5, PCl3
Ne-noble gas Cl-halogen Cu-metal
Classify each element correctly according to its type and/or the group it belongs to: Ne, Cl, Cu
Molecular Compound=composed of molecules, formed when nonmetals combine Ionic Compound=contains no molecules, formed when metals combine with nonmetals
Classify each item as molecular (covalent) compound or ionic compound: composed of molecules, contains no molecules, formed when nonmetals combine, formed when metals combine with nonmetals
Pure substance=pure silver coin, hydrogen gas, H20 mixture=salt water, gold-plated earrings
Classify each item as pure substance or mixture: salt water, pure silver coin, hydrogen gas, H20, gold-plated earrings Pure substance= mixture=
Conductor= gold, silver, copper Semiconductors= GaAs, Si, CdS insulator= plastic, concrete
Classify each material as conductor, semiconductor, or insulator based on its ability to enable the flow of electricity: GaAs, Si, plastic, concrete, gold, silver, copper, CdS
homogeneous-salt water, air heterogeneous-bean soup, soil mixed with rocks, pasta salad
Classify each of the following as a homogeneous or heterogenous mixture: air, salt water, bean soup, soil mixed with rocks, pasta salad
O3-element H2O-compound air-mixture
Classify each substance as compound, mixture, or element: O3, H20, air
Compound=two different atoms bonded together element=atoms on their own
Compound= element=
compound
Consists of two or more elements, chemically bound
element
Contains only one type of atom
gain, lose
Copper occurs in a variety of compounds in ores. Chalcocite is a mineral composed of Cu2S. In order to extract solid Cu metal from this ore, the Cu ions must ___ electrons and the S2- ions must ____ electrons.
8.35 x 10^-11
Express the quantity 0.0000000000835 (10 0s) correctly in scientific notation.
taps into a source that is far more concentrated than metal ores mined from the ground
Extracting metals by recycling electron devices...
Many metals exist as compounds of oxygen, or oxides Nonmetals such as oxygen and nitrogen may occur either in elemental form or in the form of compounds
Form(s) in which elements exist in nature:
metalloid
Has properties between those metals and nonmetals
2
How many significant figures should the answer to the following calculation contain? 2.3 x 5.26
elements, fixed
In a given chemical compound, the component ____ are present in _____ proportions by mass, regardless of the source of the compound.
is abbreviated mol indicates amount of substance
In chemistry, the mole
+2, -2
In the compound MgO, the Mg ion has a charge of ____, while the O ion has a charge of ____.
sustainability
Managing human consumption of natural resources so that these resources are not exhausted is called ____.
oxide, silicate
Many metals occur as minerals in rocks and soil. A mineral in which a metal is bonded to oxygen is called a(n) _______, whereas a mineral containing oxygen and silicon together is called a(n)___
CCl4=154.0 g/mol PF3= 88.0 g/mol SO2= 64.1 g/mol
Match each compound correctly to its molar mass: CCl4, PF3, SO2, 154.0g/mol, 88.0 g/mol, 64.1 g/mol
mass ratio of N-0.824 mass percent of N-82.4 mass ratio of H-0.176 mass percent of H-17.6
Match each element in the compound NH3 to its correct mass ratio and mass percentage: 17.6, 82.4, 0.176, 0.824
O in O2= 0 Na in NaCl= +1 O in H2O= -2 Fe in FeCl3= +3
Match each element to its correct oxidation number: O in O2, Na in NaCl, O in H2O, Fe in FeCl3
Cl- -1 Sr- +2 S- -2 Al- +3
Match each element with the appropriate charge in its ionic form: Cl, Sr, S, Al
Group 1A-Alkali metals Group 2A-Alkaline earth metals Group 7A-Halogens Group 8A-Noble Gases
Match each group in the periodic table with the correct name as indicated Group 1A- Group 2A- Group 7A- Group 8A-
He-2 Al-13 Zn-30 Rn-86
Rank the following elements correctly according to its number of protons, starting with the element that has the least number of protons at the top of the list: Zn, Rn, Al, He
is denser than glass is produced by heating aluminum oxide powder to very high temperatures
Synthetic sapphire...
1, 4
The chemical formula CCl4 indicates that there is/are ____ carbon atom(s) for every ____ chlorine atom(s)
hundred
The composition of a mixture may be expressed as a percentage. Percent means parts per
12.o g C ————- x 100% 85.o g CH2Cl2
The molar mass of CH2Cl2 is 85.0 g/mol, wile the molar mass of carbon is 12.0 g/mol. The percent of carbon in this compound is correctly expressed as
oxidation
To track the transfer of electrons in both ionic and molecular substances, we assign a(n)_____ number to each element involved. This number reflects the charge the element would have if all bonds were ionic.
ppm=parts per 10^6 parts (million) ppb=parts per 10^9 parts (billion) ppt= parts per 10^12 parts (trillion)
We often use units of ppm, ppb, and ppt to express very low concentrations. Match each unit to its correct definition: parts per 10^9 parts, parts per 10^6 parts, and parts per 10^12 parts
groundwater could be contaminated with heavy metals the solvents used to remove the plastics are not generally environmentally friendly contaminated groundwater could contribute to an increase of cancers in surrounding communities
What are the environmental challenges to extracting metals from recycled electronic devices?
number of atoms, electrons
When balancing a half-reaction, the conservation of mass is reflected by balancing the ___ on both sides of the equation, while the conservation of charge is reflected by adding ___ to the appropriate side of the reaction.
Cerium and Gadolinium
Which are rare earth metals? Gold, Cerium, Calcium, Gadolinium
There are many more known compounds than elements A compound contains two or more different elements Elements and compounds are both pure substances
Which describes an element and compound.
Na+ and Br- Ca2+ and 2F- 2 Li+ and S2-
Which ion combinations will result in an ionic compound that has a balanced number of positive and negative charges? Mg2+ and Cl-, Na+ and Br-, Ca2+ and 2F-, K+ and O2-, 2 Li+ and S2-
silicon
Which metalloid is a key component of electronic devices?
This approach assumes that consumer goods will not be recycled This approach does not encourage sustainable practices
Which of the following are limitations to the "cradle-to-grave" approach to analysis of consumer goods?
Fe2+ > Fe3+ + e-
Which of the following equations represents an oxidation half-reaction? Na+ + e- > Na, Fe2+ > Fe3+ + e-, Cl2 + 2 e- > 2 Cl
Chemical symbols are also called atomic symbols Chemical symbols are abbreviations for elements named for properties, planets, places, and people
Which of the following options correctly describe the chemical symbols for elements?
The molar mass of a molecular substance is the mass per moles of its molecules The periodic table can be used to calculate the molar mass of any substance The molar mass of oxygen is 16.00 g/mol. This means that 1 mole of oxygen atoms has a mass of 16.00 g.
Which of the following statements correctly describe molar mass?
The nonmetal gains enough electrons to attain the same number as its nearest noble gas.
Which statement correctly describes the procedure used to predict the ion formed by nonmetal elements in groups 15, 16, and 17?
mixture= physical combination of two more species pure substance= form of matter with a definite composition
mixture= pure substance=
nucleus
small region that contains almost all the mass of an atom