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