Chemistry Exam 1

The conversions between the different units of temperature.

*F=(9/5**C)+32 K=*C+273.15

mono-

1

di-

2

Ion compounds that will result in an ionic compound that has a balanced number of positive and negative charges.

2 Li+ and S^2- Ca^2+ and 2 F- Na+ and Br-

An experiment requires 42.5 g of sulfuric acid, which is easier to measure by volume than by mass. What volume in mL should be measured out, if the density of the sulfuric acid is 1.84 g/cm^3?

23.1 mL

A particular isotope of an element is represented byt he symbol 36CL17 (numbers on left side, 36 on top and 17 of bottom). The mass number of the isotope is equal to ____, and this number represents the total number of protons plus ________ in the nucleus. The atomic number of the isotope is equal to ____, and this number represents the number of ________ in the nucleus.

36, neutrons, 17, protons

penta-

5

0.000558 in Scientific Notation

5.58*10^4

hexa-

6

hepta-

7

Chemical Changes

A candle burns in air and grows steadily shorter. A log is burned and produces white ash. The composition of the substance is altered during a chemical change. The physical properties of the substance are changed during a chemical change.

Compounds

A compound is a (pure) substance. A compound has a fixed mass ratio of its components. A compound contains a fixed number of atoms in its formula.

The macroscopic view of the three states of matter.

A liquid conforms to the shape of its container. A liquid has a fixed volume. A gas conforms to both the shape and the volume of the container it is in.

Chemical Change

A log is burned and produces white ash. A candle burns in air and grows steadily shorter.

Molecule

A molecule is an independent structure consisting of two or more atoms covalently bonded together.

The information contained within a structural formula.

A structural formula contains the numbers and types of atoms in a molecule. A structural formula shows how the atoms of a molecule are bonded together.

The three temperature scales and their relationships to eachother.

Absolute zero is 0 K or -273.15*C. All temperatures in the Kelvin scale (other than 0 K) are positive. Both the Kelvin and Celsius scales have the same size degree unit.

How to name binary acids.

Acids are named differently depending on their physical state. Binary acids contain the nonmetal root and then the suffix -ic. Binary acids have the prefix hypro- to specify that they contain hydrogen.

Inorganic Compounds

All other components.

SI base units and derived units.

All the base units are based on metric units. There are 7 base units in the SI system.

Element

An element may consist of two or more of the same atoms bonded together. An element consists of only one kind of atom.

Metalloid

An element that has properties between those of metals and nonmetals.

Metal

An element that is a good conductor of heat and electricity, has a shiny surface, is malleable and ductile.

Nonmetal

An element that is generally a gas or a dull brittle solid at room temperature, and is a poor conductor of heat and electricity.

Weight and Mass

An object's weight is a result of gravitational force. The mass of an object is the amount of matter it contains. The mass of a given object is constant.

HBr

Diatomic Molecule

Law of definite proportions

Different samples of the same compound always contain its constituent elements in the same proportion by mass.

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.

Molecular Formula

Gives the actual number of atoms of each element in a molecule.

Empirical Formula

Gives the smallest whole number ratio of atoms of each element in a compound.

A change is temperature may cause a change in the physical state of a substance. A physical change resulting from a change in temperature.

Ice crystals form on cold surfaces when the temperature of humid air drops below freezing. Water vapor cools and condenses to produce liquid water. When dry ice is warmed to room temperature, the solid sublimes to form a vapor.

How to round a number correctly.

If the digit removed is greater than 5, the preceding number increases by 1. If the digit removed is a 5, the preceding number is increased by 1. Rounding at each intermediate step of a multistep calculation can introduce additional error.

Law of multiple proportions

If two elements can combine to form more than one compound, the mass of one element that combine with a fixed mass of the other element are in ratios of samll whole numbers.

PbO

Lead (II) oxide

Molecular Compounds

Many molecular compounds are binary compounds. The smallest unit of a molecular compound is called a molecule.

Law of conservation of mass

Matter can neither be created nor destroyed.

Addition and Subtraction

The answer is rounded to have the same number of digits after the decimal as the quantity with the fewest digits after the decimal.

Multiplication and Division

The answer is rounded to have the same number of significant figures as the quantity with the fewest significant figures.

How to name an ionic compound.

The cation is named first and the anion second. For a monatomic anion, the element name is changed to end in -ide.

How does a mixture differ from a pure substance?

The components of a mixture can be seperated by physical means. The composition of a mixture may vary.

Ionic Compounds

The correct chemical formula for sodium chloride (table salt) is NaCl not Na+Cl-. The formula of an ionic compound is usually written as an empirical formula. Ionic compounds are composed of cations and anions.

Millikan's oil-drop experiments

The determination of the charge on a single electron.

Rutherford's gold-foil experiment

The discovery of the nucleus of the atom.

Thomson's experiment with cathode rays

The discovery that atoms can be divided into smaller particles.

15N7 (15 on top and 7 on bottom)

The element contains 8 neutrons in its necleus. The element contains 7 protons in its nucleus.

The arrangement of the periodic table.

The elements in the upper right portion of the periodic table are nonmetals. The horizontal rows of the periodic table are called periods. Elements in the same group have similar chemical properties.

Scientific Notation

The exponent can be a positive or negative integer. One digit is present to the left of the decimal point in all cases.

The chemical formulas of ionic compounds.

The formulas of ionic compounds are usually empirical formulas. The sum of the charges of each ion that make up an ionic compound must be zero.

The mass number of an element.

The mass number is given by the sum of the protons and neutrons in the nucleus. The mass number is often written as a left superscript next to the atomic symbol. The mass number of an element is given the symbol A.

How to name a binary molecular compound.

The name of the first element remains unchanged, except for the addition of a prefix where appropriate. A Greek numerical prefix is used to indicate the number of atoms of each element in the compound. The second element is named with its root and the suffic -ide.

Atomic Structure

The number of protons equals the number of electrons in a neutral atom. The protons and neutrons together comprise most of the mass of the atom. The nucleus comprises a very small fraction of the total volume of the atom.

Physical Change

The physical form of the substance changes during a physical change. The chemical composition of the substance is not altered during a physical change.

The digit removed is 5 or greater than 5.

The preceding number increases by 1.

The digit removed is less than 5.

The preceding number remains unchanged.

Element symbols that are written in the correct format.

The symbol for magnesium is Mg. The formula CO indicates that there are two elements present. Carbon has the symbol C.

The observations that led to the development of the nuclear model of the atom.

Thomson measured the mass/charge ratio for an electron. The discovery of cathode rays led to an understanding that the atom contains smaller particles. Rutherford determined that the main mass of the atom is concentrated in a central region.

The chemical formula of the ionic compound that is composed of Ti^4+ and O^2- ions.

TiO2

What information is contained is a chemical formula?

Types of elements present in a compound. Ratio of elements in a compound.

Neutron

Uncharged dense particle located in the center of the atom.

The significance of zeros in a reported number.

Zeros to the left of the first nonzero digit are not significant. Zeros to the right of the number are significant as long as there is a decimal point present.

Group 1A

alkali metals

Group 2A

alkaline earth metals

NH3

ammonia

An ion with more electrons than its neutral atom is called a(n) ___________.

anion

Z

atomic number: the number of protons in the nucleus

X

atomic symbol: the element symbol found on the periodic table

Isotopes are atoms of the same element that have the same ______ number but a different _______ number. This is because isotopes have the same number of protons but a different number of _______.

atomic, mass, neutrons

When naming a binary molecular compound, the number of ________ of each element is indicated by a Greek numerical _______. The first element in the name is numbered only when more than _________ atom of that element is present.

atoms, prefix, one

Al (atomic number 13) ________ 3 electrons to form the Al^3- ion, which therefore contains a total of ________ electrons.

loses, 10

A

mass number: the total number of protons and neutrons in the nucleus

The _____ number of an atom is equal to the sum of the protons and _______ in the nucleus of the atom.

mass, neutrons

The _______ number of an atom is equal to the sum of the protons and ________ in the nucleus of the atom.

mass, neutrons

Chemistry is the study of matter, which is commonly defined as anything that has _______ and occupies _______.

mass, space

Chemistry is the study of matter, which is commonly defined as anything that has _________ and occupies _________.

mass, volume

Densisty is defined as the ratio of _____ to _______ for a substance or sample.

mass, volume

Chemistry is the study of _________.

matter and its composition the changes of matter the properties of substances

Ionic compounds are made up of cations and anions. All cations in ionic compounds except NH4^+ are derived from _______ atoms.

metal

CH4

methane

The ________ formula shows the exact number of atoms of each element in the smallest unit of a substance.

molecular

The charge of an ion with more electrons than its neutral atom is _______.

negative

Ionic compounds are electrically _______ overall. Therefore, the sum of the charges on the cation and anion in each formula unit must be equal to _______.

neutral, zero

NO2

nitrogen dioxide

When water changes from a solid to liquid, the H2O particles present in the solid form become H2O particles in the liquid form. During this process there is ________ in the chemical composition of the substance. This is defined as a(n) _________ change.

no change, physical

Group 8A

noble gases

An atom is composed of a very dense central _______ containing _______, which are positively charged, and neutrons, which have ________ electrical charge.

nucleus, protons, neutral

The chemical formula of carbon tetrachloride (CCl4) tells us that a molecule of this compound contains ______ carbon atom(s) and ________ chlorine atom(s).

one, four

Which two elements do oxoacids always contain?

oxygen hydrogen

An element is the simplest form of matter that has unique ________ and chemical properties. An element consists of only one kind of ________.

physical, atom

The charge of an ion with fewer electrons than its neutralatom is _______.

positive

Each element has a unique number of _______, which is called the atomic number. For an electrically neutral atom, this number is also equal to the number of _____ present.

protons, electrons

The color of a sports drink represents ________ data, whereas the exact amount of food coloring added to the drink represents _________ data.

qualitative, quantitative

A conversion factor is a(n) ________ used to express a quantity in different units of measurement. Multiplying by a conversion factor is the same as multiplying by ___ because the numerator and denominator are equivalent.

ratio, 1

Every measuremtn includes some uncertainty, which is usually assumed to be reflected by the ______ digit of the number. All the digits recorded in a measurement are called the _______ figures of the measurement.

rightmost, significant

The compound MgS is correctly named magnesium _________.

sulfide

To represent an ion, the charge on the ion is written as a right _______ next to the element symbol. If the charge is a number other than one, the number is usually written _______ the positive or negative sign.

superscript, before

When adding or subtracting numbers in scientific notation the exponent of the product will be _________.

the same as the exponents of the numbers being added

When multiplying numbers in scientific notation the exponent of the product will be _______.

the sum of the exponents of the numbers being multiplied

H2O

water

The correct name for HI when dissolved in aqueous solution is ________.

hydroiodic acid

A(n) ______ compound is composed of cations and anions

ionic

In the Stock system Roman numerals are used to name ______ compounds containing a metal that can form more than one ________. The Roman numeral specifies the ________ on the metal.

ionic, ion, charge

An ionic compound consists of a three-dimensional ______ of ions. Each cation is surrounded by anions and vice versa, so that there is no individual unit of the compound. The chemical formula of an ionic compound is always written as the simplest or _____ formula.

lattice, empirical

What is the basic unit of an element that can enter into chemical combination?

Atom

The correct chemical formula for barium hydride.

BaH2

The most common form of each element at room temperature.

Cl2 O2

Dalton's atomic theory

Compounds result from the combination of a specific ratio of atoms of different elements. Atoms of the same element are identical. All matter consists of atoms.

Organic Compounds

Contain C, usually in combination with elements such as H, N, O, or S.

dinitrogen pentoxide

N2O5

Electron

Negatively charged particle.

Solid

Particles close together and organized.

Liquid

Particles close together but not held rigidly in position.

Gas

Particles far apart and disorganized.

Data

Pieces of quantitative information collected through observation.

C6H12O6

Polyatomic Molecule

Proton

Positively charged particle found within the center of the atom.

Chemical Properties

Properties that a substance displays as it transforms into or associates with another substance or substances.

Physical Properties

Properties that can be measured without changing the identity or composition of a substance.

Variable

Quantity that can have more than a single value; controlled in an experiment.

What information is contained in a chemical formula?

Ratio of elements in a compound. Types of elements present in a compound.

The correct formula for rubidium sulfate.

Rb2SO4

The correct chemical formula for sulfur tetrafluoride.

SF4

Experiment

Set of steps designed to test a hypothesis.

Structural Formula

Shows the relative placement and connections of atoms in a molecule.

Nucleus

Small region that contains almost all of the mass of an atom.

The procedure used to determine the number of significant digits in a reported quantity.

Start at the left and move right until you reach the first nonzero digit. "Trailing zeros" to the right of the nonzero number may or may not be significant. For a quantity without a decimal point, it is usually assumed that railing zeros are not significant. The use of scientific notation eliminates this ambiguity. All digits from the first nonzero digit onward (going to the right) are significant, if there is a decimal point.

Processes that require heat to occur.

Tap water is boiled in a large pot. Solid carbon dioxide (dry ice) sublimes to the gaseous form.

Hypothesis

Testable proposal made to explain observations or data.

SI base quantities and their units.

The SI unit for length is the meter. The correct abbreviation for kelvin is K.

The SI base quantities and their units.

The Si unit for length is the meter. The correct abbreviation for kelvin is K.

An ion with fewer electrons than its neutral atom is called a(n) ________.

cation

When naming an ionic compound, the _______ is always named first. To name the anion, the root of the nonmetal name is added to the suffix -_______. The anion O2- is therefore named _______.

cation, ide, oxide

Ionic Compound

cesium iodide potassium chloride

During a chemical change or reaction, a substance is changed into one or more differetn substances. The ________ composition and the physical _________ of the new substance(s) will be different from those of the original substance.

chemical, properties

The ionic compound CrCl3 is correctly named _________.

chromium (III) chloride

The compound Cu2O is correctly named ________.

copper (I) oxide

Use the nomenclature rules to name the molecular compound Cl2O7 correctly.

dichlorine hetoxide

A compound consists of two or more different ________ that are chemically bonded together in fixed proportions. A compound can be broken down into simpler substances, a process that involves a(n) ________ change.

elements, chemical

A number that is part od a unit definition has an infinite number of significant figures associated with it and is a called a(n) ________ number. Such numbers do not determine the number of _________ figures in an answer.

exact, significant

The anion formed by the element fluorine is called _______ and the anion formed by the element chlorine is called ________.

fluoride, chloride

Chemists use chemical _________ to express the composition of molecules and ionic compounds in terms of chemical symbols.

formulas

Group 7A

halogens

A student carried out an experiment using a circular piece of aluminum foil (of known thickness) to determine the value of pie. The accepted value of pie is 3.1416. The student's results were 3.6689, 3.6691, 3.6687, and 3.6693. What is the best statement about this student's results in regard to precision and accuracy.

high precision and low accuracy