Chem 155- Chapter 1
proton's charge
+1
electron's charge
-1
neutron's charge
0
electron's weight
0 amu
neutron's weight
1 amu
proton's weight
1 amu
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: Rn, He, Al, Zn
1. He 2. Al 3. Zn 4. Rn
12/6 C. what does each symbol represent
12- mass number (protons + electrons) 6- atomic number (number of protons and electrons) C- element, Carbon
which of the following reflects the correct procedure to calculate the molar mass of CH2Cl2
12.0 + 2(1.0) + 2(35.5) = 85.0g/mol
an atom of chlorine has a mass of 36. this atom has ___ protons and ___ neutrons in its nucleus
17; 19
the chemical formula CCl4 indicates that there is/are ___ carbon atoms for every ___ chlorine atom
1; 4
convert 20nm to m, given: 1nm= 1x10^-9m
20nm x (1x10^-9m)/1nm
specify the number of protons and electrons in a neutral atom of chromium
24 protons, 24 electrons
.00005
5x10^-2
0.05
5x10^-2
500
5x10^2
50,000
5x10^4
5,000,000
5x10^6
which of the following chemical symbols are correct: C is carbon CO is cobalt Ar is argon I is iron
C is carbon Ar is argon
which of the following elements commonly occur as diatomic molecules
Fl, O, N, H
examples of covalent compounds
N2O5, CO2, PCl3
examples of ionic compounds
NiO, FeCl3, NaBr
which of the following are elements
O2, Na, Cu
what is H2O
a comound
metal is
a good conductor of heat and electricity
what is air
a mixture
which of the following correctly defines a molecule
a molecule is independent structure consisting of two or more atoms chemically bonded together
homogeneous mixture examples
air, salt water
which of the following options correctly describe the characteristic behavior of the elements in a particular group on the periodic table
alkali metals and alkaline earth metals make soil and water alkaline noble gases are generally unreactive
different forms of the same element like O2 and O3 are called ____. these forms differ in the way the atoms are bonded together
allotropes
what is O3
an element
the smallest unit of an element that can exist as a stable independent entity is an
atom
a molecule is an independent structure composed of two or more ____ chemically bonded together
atoms
heterogeneous mixture examples
bean soup, soiled mixed with rocks, pasta salad
which of the following statements correctly describe different forms of matter
both mixtures and pure substances are forms of matter mixtures can consist of any four phases of matter
minerals are
chemical compounds found in rocks and soil
which of the following options correctly describes the chemical symbols for the elements
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
molecular compound
composed of molecules formed with nonmetals combine
most elements occur in nature as
compounds
compound
consists of two or more elements chemically bonded
ionic compound
contains no molecules formed when metals combine with nonmetals
element
contains only one type of atom
mixture
contains two or more different substance which can usually be physically separated
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
insulator
does not allow the flow of electricity
in a given chemical compound, the component ___ are present in ___ proportion by mass, regardless of the source of the compound
elements; fixed
conductor
enables the flow of electricity
a chemical ____ (e.g., CO2) represents the elementary composition of any pure substance
formula
elements in group 17 are called ____, whereas elements in group 18 are called ____ gases
halogens; noble
pure substance
have uniform composition and are composed of only one type of particle
give the name of the "lightest" element in Group 8A
helium
the composition of a mixture may be expressed as a percentage. percent means parts per
hundred
pure substances examples
hydrogen gas a pure silver coin H2O
neutron's location
in the nucleus
proton's location
in the nucleus
semiconductors
include metalloids such as silicon are less conductive than metals enable a flow of electricity
the accuracy of calculation is limited by the quantity that has the ___ number of significant figures
least
which of the following options correctly describes the forms in which elements exist in nature
many metals exist as compounds of oxygen or oxides nonmetals like O or N may occur in either elemental form or in the form of compounds
chemistry is the study of matter, which is commonly defined as anything that has ___ and occupies ___
mass, space
what is calcium
metal
what is silicon
metalloid
silicon is a key component of electronic devices. this element is a ___, a type of element also called a
metalloid; semiconductor
which of the following correctly describe different forms of matter
mixtures can consist of any four phases of matter both mixtures and pure substances are forms of matter
chemists use the ___ as a unit of amount of a substance
mole
the molar mass of any substance is the mass of 1 ___ of the particles of that substance
mole
what is Sulfur
nonmetal
electron's location
outside the nucleus
metalloid has
properties between those of metals and nonmetals
mixture examples
salt water gold-plated earrings
a ____ figure is a digit that represents the accuracy with which an experimental quantity if known
significant
which of the following are examples of mixtures
soil tap water
managing human consumption of natural resources so that these resources are not exhausted is called
sustainability
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
a crade-to-cradle approach to analysis of the life 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
which of the following form the focus of the cradle-to-grace approach to consumer goods
the energy consumed to produce the goods the waste products created when the goods are made the raw materials from which the goods are made
give the name and chemical symbol for the element with 54 protons
xenon, Xe
how many sig figs should be the answer to the following calculation contain: 2.3 x 5.46
2
nonmetal is
a poor conductor of heat and electricity
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
is CO2 molecular or ionic
molecular
this half reaction: Ni -> Ni 2+ + 2e- represents the process of ___ because electrons are _____
oxidation; lost
many metals occur as minerals in rocks and soil. a mineral in which a metal is bonded to oxygen is called ____, whereas a mineral containing oxygen and silicon together is called a ____
oxides; silicates
which of the following statements correctly describes the atomic number of an element
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 options correctly describe mixtures
the components can be separated by physical means the proportions of the components vary
which of the following options correctly describe the mass number of an atom
the mass number is given by the sum of protons and neutrons in the nucleus the mass number may vary between atoms of a particular element
which of the following statements correctly describe subatomic particles
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
an electric current is
the movement of charged particles such as electrons or ions
which of the following options correctly describes the periodic table
the periodic table contains the chemical symbols that represent the elements the elements in the periodic table are arranged based on similar chemical properties
