Unit 1
Which of the following form the focus of the "cradle-to-grave" approach to consumer goods? Select all that apply.
The energy consumed to produce the goods The raw materials from which the goods are made The waste products created when the goods are made
Silica glass is made by ________.
heating sand to a temperature high enough to melt it and then cooling the liquid until it hardens
The atomic number is the
number of protons in a nucleus.
Which of the following elements are commonly added to sand when making glass, to improve its thermal properties? Select all that apply.
Boron (B) Aluminum (A) Potassium (K)
Which of the following are physical changes? Select all that apply.
Breaking a bottle Melting ice
flourine =
F
Iron =
Fe
Hydrogen =
H
Which of the following elements commonly occur as diatomic molecules? Select all that apply.
N O F H
The most common elemental form of nitrogen is ______.
N2
Sulfur =
S
Silicon =
Si
Which of the following are examples of mixtures? Select all that apply.
Soil and tap water
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
Which of the following are examples of chemical changes? Select all that apply.
burning a candle rusting of iron
Minerals are _______.
chemical compounds found in rocks and soil
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
A solid that has a highly ordered structure at the atomic level is referred to as a(n) ______, whereas solids with a relatively disordered structure are described as _______.
crystal; amorphous
On a periodic table, the columns of elements with similar properties are
groups
Is blood a heterogeneous or homogeneous mixture?
heterogenous (becuase it is not clear)
Sulfur is a
nonmetal
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
Chemistry is the study of ______. (Select all the options that correctly complete the sentence.)
the changes of matter matter and its composition the properties of substances
atomic number
the number of protons in the nucleus of an atom, which determines the chemical properties of an element and its place in the periodic table.
Nuetron
uncharged dense particle located in the center of the atom
Which of the following options correctly describe atoms? Select all that apply.
-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 are extremely small.
Which of the following options describe the correct format used when writing the chemical formula of a substance? Select all that apply.
-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.
Which of following options correctly describe the periodic table? Select all that apply.
-The periodic table contains the chemical symbols that represent the elements. -The elements in the periodic table are arranged based on similar chemical properties.
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 air samples are toxic? Select all that apply.
0.9 ppm SO2 5.0 × 102 μg/m3 of NO2
Which differentiates a compound from a mixture of two or more elements?
A compound does not exhibit the individual properties of the elements of which it is composed
Which of the following statements correctly defines a molecule?
A molecule is independent structure consisting of two or more atoms chemically bonded together.
Silver =
Ag
Group 1=
Alkali metals
Argon =
Ar
Carbon =
C
Calcium =
Ca
Which of the following options correctly describe the chemical symbols for elements? Select all that apply.
Chemical symbols are also called atomic symbols. Chemical symbols are abbreviations for elements named for properties, planets, places, and people.
The periodic table is organized such that elements with similar _____ properties fall into vertical columns called _____.
Chemical; groups
Cobalt =
Co
Which of the following options correctly describe elements and compounds? Select all that apply.
Elements and compounds are both pure substances. There are many more known compounds than elements. A compound contains two or more different elements.
Group 17 =
Halogens
Solid compounds of metals found in rocks and soil are called _____.
Minerals
Nitrogen=
N
Sodium =
Na
is air a pure substance?
No. It is a mixture.
Group 18=
Noble gases
The elements on the right side of the periodic table are:
Nonmetals
Which of the following options correctly describe the form(s) in which elements exist in nature? Select all that apply.
Nonmetals such as oxygen and nitrogen may occur either in elemental form or in the form of compounds. Many metals exist as compounds of oxygen, or oxides.
Which of the following are elements? O2 Na NaCl Cu CaCo3
O2 Na Cu
Which of the following are allotropes of oxygen?
O2 O3
Which of the following options correctly describe silica? Select all that apply.
Quartz is a form of silica. Silica is a naturally occurring substance. Silica has a well-ordered structure composed of repeating linkages between Si and O.
Sulfur=
S
Which of the following options correctly describe different samples of matter? Select all that apply.
Tap water is an example of a mixture. CO2 is an example of a molecule.
Which of the following statements correctly describe the atomic number of an element? Select all that apply.
The atomic number is equal to the number of protons in the nucleus. Each element has its own unique atomic number.
Which of the following statements correctly describe subatomic particles? Select all that apply.
The mass of an electron is much smaller than the mass of a proton. Protons are positively charged. The electrons are located outside the nucleus of an atom.
What distinguishes the atoms of one element from another?
The number of protons
What are the environmental challenges to extracting metals from recycled electronic devices? Select all that apply.
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.
T/F Only 118 elements exist but over 20 million compounds have been isolated and characterized.
True
Classify each substance correctly according to type. (mixture, element, compound) O3 H2O air
air= mixture O3= element H2O= compound
Group 2 =
alkaline earth metals
A molecule is an independent structure composed of two or more _____ chemically bonded together.
atoms
A substance that can be broken down into two or more simpler substances by chemical methods is called a(n)
compound
Most elements occur in nature as ______.
compounds
A chemical _____ (e.g., CO2) represents the elementary composition of any pure substance.
formula
Calcium is a
metal
silison is a
metalloid
CH4
methane
NaCl(aq) is a pure element, pure compound, or mixture?
mixture
A(n) __________ is a fixed number of atoms held together by chemical bonds in a certain spatial arrangement.
molecule
Electron
negatively charged particle
Proton
positively charged particle found within the center of the atom
parts per 109 parts
ppb
parts per 106 parts
ppm
parts per 1012 parts
ppt
The nucleus of an atom contains
protons and neutrons only
nucleus
small region that contains almost all the mass of an atom
When an electronic device is recycled, the metals are recovered by _____.
treatment with strong acid