CHM1020 (Chemistry) Ch. 1
In the compound MgO, the Mg ion has a charge of ________, while the O ion has a charge of ________.
+2; -2
How many significant figures should the answer to the following calculation contain? 2.3 x 5.46 = ________
2
Which of the following equations represents a reduction half-reaction?
2H^+ +2e^- ---->H2
Express the quantity 0.0000000000835 correctly in scientific notation.
8.35 x 10^-11
Match each element with the appropriate charge in its ionic form.
Cl = -1 Sr = +2 S = -2 Al = +3
In the compound CrCl3 ________.
Cl has a -1 charge Cr has a +3 charge
Match the name of each element correctly to its symbol.
Na = sodium N = nitrogen S = sulfur Si = silicon Ag = silver
Match each element to its correct oxidation number.
O in O2 = 0 Na in NaCl = +1 O in H2O = -2 Fe in FeCl3 = +3
The composition of a mixture may be expressed as a percentage. Percent means parts per ________.
hundred
We often use units of ppm, ppb, and ppt to express very low concentrations. Match each unit to the correct definition.
ppm = parts per 10^6 parts ppb = parts per 10^9 parts ppt = parts per 10^12 parts
Managing human consumption of natural resources so that these resources are not exhausted is called ________.
sustainability
Which of the following statements correctly describe the atomic number of an element?
Each element has its own unique atomic number. The atomic number is equal to the number of protons in the nucleus.
Which of the following elements are commonly added to sand when making glass, to improve its thermal properties?
Potassium Boron Aluminum
Different forms of the same element (such as O2 and O3) are called ________. These forms differ in the way the atoms are bonded together.
allotropes
Sapphire is a natural gemstone that is harder than quartz. Sapphire is composed of ________.
aluminum oxide
Rare earth metals are used to produce ________.
catalytic converters in motor vehicles rechargeable batteries cell phone speakers
An atom of nitrogen (N) has a mass number of 15. This atom ________.
contains 7 protons in its nucleus. contains 8 neutrons in its nucleus.
An electric current is the net movement of ________.
electrons
Nanotechnology is concerned with science on what scale?
1 x 10^-9 m
When considering the most responsible end-use of a product, sustainability should take into account ________.
1. Environmental aspects such as preventing pollution 2. The need to improve the quality of life for all members of society 3. The fair distribution of resources
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.
1. He 2. Al 3. Zn 4. Rn
Match each of the following types of element with the correct description.
Metal - good conductor of heat and electricity Nonmetal - poor conductor of heat and electricity Metalloid - has properties between those of metals and nonmetals
Categorize each type of compound correctly.
Molecular compound: -composed of molecules -formed when nonmetals combine Ionic compound: -contains no molecules -formed when metals combine with nonmetals
Hematite is an iron ore containing Fe2O3. To obtain solid Fe metal from this ore ________.
O^2- ions will be oxidized Fe^3+ ions must be reduced the balanced half-reaction is Fe^3+ + 3e^- ----> Fe
Categorize each sample of matter correctly according to its composition.
Pure substance: -a pure silver coin -hydrogen gas -H20 Mixture: -salt water -gold-plated earrings
Classify each element according to its general position on the periodic table.
S = nonmetal Ca = metal Si = metalloid
Which of the following options correctly describe different samples of matter?
Tap water is an example of a mixture. CO2 is an example of a molecule.
Which of the following options correctly describe the mass number of an atom?
The mass number may vary between atoms of a particular element. The mass number is given by the sum of the protons and neutrons in the nucleus.
Which statement correctly describes the procedure used to predict the ion formed by nonmetal elements in Groups 15, 16, and 17?
The nonmetal gains enough electrons to attain the same number as its nearest noble gas.
In most modern touchscreens ________.
a conductive object touching the screen distorts the electric field layers of conductive wires are sandwiched between insulating surfaces
In a given chemical compound, the component ________ are present in ________ proportions by mass, regardless of the source of the compound.
elements; fixed
A conversion factor is the 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.
equivalent; 1
The accuracy of a calculation is limited by the quantity that has the ________ number of significant figures.
least
Chemists use the ________ as a unit of amount of substance.
mole
10 mm (millimeters) are equivalent to 1 cm (centimeter). To convert 15 cm to mm, you would ________.
multiply by 10
The chemical formula CCl4 indicates that there is/are ________ carbon atom(s) for every ________ chlorine atom(s).
one four
Scientific notation expresses a quantity with a single digit before the decimal point and followed by ________ raised to the appropriate power.
ten
An ore is ________.
a rock containing a significant concentration of a desirable metal
A molecule is an independent structure composed of two or more ________ chemically bonded together.
atoms
A material will conduct electricity more readily if ________.
the material is made of metal its electrons are mobile
Which of the following are rare earth metals?
Gadolinium (Ga) Cerium (Ce)
Which of the following ion combinations will result in an ionic compound that has a balanced number of positive and negative charges?
2Li^+ and S^2- Ca^2+ and 2F^- Na^+ and Br^-
Which of the following options correctly describe the chemical symbols for elements?
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 fluxes used in making glass?
Common fluxes include MgCO3 and CaCO3. Fluxes make the molten glass less viscous and easier to work. A flux lowers the melting point of the sand, thus lowering the temperature required for making the glass.
Match each type of material to the correct description.
Conductor - enables the flow of electricity Insulator - does not allow the flow of electricity
Classify each material according to its ability to enable the flow of electricity.
Conductor: -copper -silver -gold Semiconductors: -Si -GaAs -CdS Insulator: -plastic -concrete
Classify each compound correctly as either a covalent or ionic compound.
Covalent compound: -CO2 -PCl3 -N2 O3 Ionic compound: -NiO -FeCl3 -NaBr
Match each type of solid with the correct description.
Crystal - highly ordered arrangement of constituent particles Amorphous - disordered/random arrangement of constituent particles
Which of the following options correctly describe elements and compounds?
Elements and compounds are both pure substances. A compound contains two or more different elements. There are many more known compounds than elements.
Which of the following elements commonly occur as diatomic molecules?
Fluorine Hydrogen Oxygen Nitrogen
Match each solid with the correct description.
Glass - random array of silicon and oxygen linkages throughout the solid Quartz - pure crystallized SiO2 with a highly ordered arrangement at the atomic level
Classify each of the following mixtures correctly.
Homogeneous: -air -salt water Heterogeneous: -pasta salad -soil mixed with rocks -bean soup
Match each group on the periodic table with the characteristic behavior of the elements belonging to it.
Noble gases - generally unreactive Alkali metals - make soil and water alkaline Alkaline earth metals - result in hard water
Match each component of the atom with the correct description.
Nucleus - small region that contains almost all the mass of an atom Electron - negatively charged particle Proton - positively charged particle found within the center of the atom Neutron - uncharged dense particle located in the center of the atom
Match each process with the correct description.
Oxidation - loss of electrons Reduction - gain of electrons
High-tech devices may save energy because they are more energy efficient when being used, but their production requires more energy because ________.
The design process may use a great deal of energy The diverse materials required increase cost of production and manufacturing Microprocessors require an energy-intensive process to fabricate
which of the following options correctly describe the periodic table?
The elements in the periodic table are arranged based on similar chemical properties. The periodic table contains the chemical symbols that represent the elements.
What are the environmental challenges to extracting metals from recycled electronic devices?
The solvents used to remove the plastics are not generally environmentally friendly. Contaminated groundwater could contribute to an increase of cancers in surrounding communities. Groundwater could be contaminated with heavy metals.
Which of the following form the focus of the "cradle-to-grave" approach to consumer goods?
The waste products created when the goods are made The raw materials from which the goods are made The energy consumed to produce the goods
Which of the following are limitations of the "cradle-to-grave" approach to analysis of consumer goods?
This approach does not encourage sustainable practices. This approach assumes that consumer goods will not be recycled.
The smallest unit of an element that can exist as a stable independent entity is an ________.
atom
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.
cradle-to-cradle
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-grave
A chemical ________ (e.g., CO2) represents the elementary composition of any pure substance.
formula
The molar mass of any substance is the mass of 1 ________ of the particles of that substance.
g/mol
Which metals could usefully be recovered from electronic devices?
gold silver
A ________ is a type of chemical equation that shows the electrons either lost or gained by the reactants.
half-reaction
Elements in Group 17 are called ________, whereas elements in Group 18 are called ________ gases.
halogens noble
A ________ mixture is uniform throughout, whereas a ________ in not uniform and different components can be distinguished.
homogeneous; heterogeneous
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 ________.
mass charge
Chemistry is the study of matter, which is commonly defined as anything that has ________ and occupies ________.
mass space
The ________ number of an atom is equal to the total number of protons and ________ in the nucleus of the atom.
mass; neutrons
Sustainability is correctly defined as ________.
meeting present needs without compromising the ability of future generations to do the same
Silicon is a key component of electronic devices. This element is a ________, a type of element also called a ________.
metalloid; semiconductor
Solid compounds of metals found in rocks and soil are called ________.
minerals
To track the transfer of electrons in both ionic and molecular substances, we assign an ________ number to each element involved. This number reflects the charge the element would have if all bonds were ionic.
oxidation
Many metals occur as minerals in rocks and soil. A mineral in which a metal is bonded to oxygen is called an ________, whereas a mineral containing oxygen and silicon together is called a ________.
oxide silicate
Each element has a unique number of ________, which is called the atomic number. For a neutral atom, this number is also equal to the number of ________ present.
protons; electrons
Silica is a naturally occurring oxide of silicon, SiO2, which is transparent. Pure crystallized SiO2 is known as ________.
quartz
A ________ figure is a digit that represents the accuracy with which an experimental quantity is known.
significant
Hematite is an iron ore containing Fe2 O3. To obtain solid Fe metal from this ore ________.
the balanced half-reaction is Fe^3+ + 3e^- ----> Fe O^2- ions will be oxidized Fe^3+ ions must be reduced
A "cradle-to-grave" approach to analysis of the life of cycle of an item includes the idea that ________.
the end of the life cycle of one item leads naturally into the beginning of the life cycle of another
An electric current is ________.
the movement of charged particles such as electrons or ions
If a mixture of quartz and bauxite contains 78% quartz, this means that ________.
there are 78 g of quartz in 100 g of the mixture there are 78 g of quartz for every 22 g of bauxite 150 g of this mixture contains 117 g of quartz
Which of the following options correctly describe mixtures?
The components can be separated by physical means. The proportions of the components can vary.
Most elements occur in nature as ________.
compounds
Synthetic sapphire ________.
is denser than glass is produced by heating aluminum oxide powder to very high temperatures