Chem Comp + others

Physical Property

Physical Property

A property that can be observed, measured, or changed without changing the substance itself.

Matter

Anything that has mass and takes up space.

State/Phase of Matter

A form that matter can take - solid, liquid, or gas.

Characteristic Property

A quality of a substance that never changes and can be used to identify the substance

Physical Change

A change in a substance that does not change its identity

Chemical Property

a property of matter that describes a substance's ability to become a new substance

Chemical Change

A change that occurs when one or more substances change into entirely new substances with different properties.

Density

Mass per unit volume

Mass

the amount of matter in an object

volume

The amount of space an object takes up

evidence of chemical change

gives off a gas (bubbles), changes color (not always), temperature change, forms a precipitate, change in odor

A physical change is reversible

sometimes true

a chemical change is reversible

false

Which of the following is not an example of a physical property?

color

Which of the following is not an example of a chemical property?

texture

flammability

the ability of a substance to burn easily

What is the density of water?

The density of water is 1 g/cm3

Mass is a

chemical property

A substance's __________________________ properties predict how it will react with other substances.

chemical

T or F? You cannot classify matter based on chemical properties.

True

Mass is the amount of matter in an object. __________________________ is the gravitational pull on the mass of an object

Weight

Which formula listed below correctly finds density?

D= g/v

Law of Conservation of Mass

Matter is not created nor destroyed in any chemical or physical change

chemical formula

A combination of chemical symbols and numbers to represent a substance

reactants

the starting material in a chemical reaction; usually on the left side of a chemical equation

products

the substances that are formed by the chemical change; usually on the right side of a chemical equation

open system

A system in which matter can enter from or escape to the surroundings.

closed system

A system in which no matter is allowed to enter or leave

polar molecule

molecule with an unequal distribution of charge, resulting in the molecule having a positive end and a negative end

element

any substance that cannot be broken down into simpler substances

atom

The smallest component of an element having the chemical properties of the element

nucleus

the center of an atom

isotopes

atoms of the same element that have different numbers of neutrons

compound

a substance that is composed of atoms of to or more different elements that are chemically combined

covalent bond

a chemical bond that involves sharing a pair of electrons between atoms in a molecule

molecule

Is a group of atoms held together by covalent bonds.

ionic bond

the attractive force between two ions of opposite charge

metabolism

all of the chemical reactions that occur within an organism

mixture

combination of substances in which individual components retain their own properties

solution

mixture of two or more substances in which the molecules of the substances are evenly distributed

pH

measure of how acidic or basic a solution is

acid

any compound that forms H+ ions in a solution

base

compound that produces hydroxide ions (OH-) in solution

hydrogen bond

weak chemical bond formed by the attraction of positively charged hydrogen atoms to other negatively charged atoms

diffusion

The process by which molecules move from an area of higher concentration to an area of lower concentration.

isomers

compounds that have the same numbers of atoms of the same elements but different structures and hence different properties

polymer

large molecule formed when many smaller molecules bond together

carbohydrate

any organic compound that is made of carbon, hydrogen, and oxygen and that provides nutrients to the cells of living things

amino acids

the building blocks of proteins

peptide bond

covalent bond formed between amino acids.

enzyme

a protein that changes the rate of a chemical reaction

nucleic acid

complex macromolecule that stores cellular info in the form of a code

nucleotides

Nucleic acids are polymers made of smaller subunits

What does the octet rule state that explains why atoms bond?

An atom bonds to have eight valence electrons to become stable.

The diagram shows an electron shell model of a sodium atom. How would the model change as the atom forms bonds?

The third shell would be empty so that the eight electrons in the second level would be outermost after the atom loses one electron.

Atoms of which elements form bonds without satisfying the octet rule?

helium (He) and hydrogen (H)

Based on the location of nitrogen (N) on the periodic table, how many additional electrons does a nitrogen atom need in its valence shell to satisfy the octet rule when it forms bonds?

three

What is the most likely way in which an atom of magnesium (Mg) will satisfy the octet rule when it forms bonds?

by losing two electrons

Fluorine (F) and bromine (Br) are in the same group on the periodic table. How do atoms of these elements compare when they form bonds?

Both a fluorine atom and a bromine atom gain one electron, and both atoms become stable.

A force that holds atoms together is a chemical

bond

When sodium atoms (Na) and chlorine atoms (Cl) join to make sodium chloride, or table salt, they form an ionic bond. Using this information, which pair of elements is most likely to form an ionic bond?

metal and nonmetal

An atom of lithium (Li) forms an ionic bond with an atom of fluorine (F) to form lithium fluoride. How are the valence electrons of these atoms rearranged to form this bond and what proportion is needed?

Electrons are transferred from the lithium atom to the fluorine atom. 1 lithium ion and 1 fluoride ion will form (LiF)

Metal atoms tend to give away valence electrons when they bond with nonmetal atoms. What type of bond will form between the metal and nonmetal atoms and why does this bond form?

An ionic bond will form because electrons are transferred.

Lead is malleable, so it can be pounded into flat sheets without breaking. How does the bonding within lead help to explain this property?

Metallic bonds involve many valence electrons shared by many atoms, so the bonds can move around as the metal is pounded.

How many dots belong in the electron dot diagram of a boron (B) atom?

three

Sal drew the electron dot diagram of an aluminum atom. How should Sal correct his diagram?

He should add a single dot to the symbol.

Sunni drew an electron dot diagram of a silicon atom. In addition to changing the symbol to C, how would this diagram compare with an electron dot diagram of a carbon atom (C)?

The same number of dots would appear in the diagram for carbon.

What information on the periodic table is used to complete electron dot diagrams?

The number of valence electrons is represented by the dots in the electron dot diagrams.

The electron dot diagram shows the arrangement of dots without identifying the element. Which element symbol's could replace the question mark in the diagram?

nitrogen (N), phosphorus (P), and arsenic (As)

The electron dot diagram shows the arrangement of dots without identifying the element. Which element symbol's could replace the question mark in the diagram?

oxygen (O), sulfur (S), selenium (Se), and tellurium (Te)

Covalent Bond

sharing of electrons (occurs between nonmetals)

Polar Covalent Bond

Unequal sharing/pulling of electrons between nonmetals (use electronegativity difference to determine if a bond is polar - if the EN difference is above 0.3 assume it is a polar covalent bond)

Nonpolar Covalent Bond

Equal sharing/pulling of electrons between nonmetals (if EN difference is 0, 0.1, or 0.2 assume it is a nonpolar covalent bond)

Single Bond

2 electrons (or 1 pair of electrons) being shared between 2 atoms (also called a sigma bond)

Double Bond

4 electrons (or 2 pairs of electrons) being shared between 2 atoms (made up of 1 sigma bond and 1 pi bond)

Triple Bond

6 electrons (or 3 pairs of electrons) being shared between 2 atoms (made up of 1 sigma and 1 pi bond)

Hybridization (hybrid orbitals)

sp, sp2, sp3

linear shape (180 bond angle)

central atom hybridization is sp

bent shape (close to 109.5 bond angle)

central atom hybridization is sp3

trigonal planar shape (120 bond angle)

central atom hybridization is sp2

trigonal pyramidal shape (close to 109.5 bond angle)

central atom hybridization is sp3

tetrahedral shape (109.5 bond angle)

central atom hybridization is sp3

Polar Molecule (not the same as a polar bond)

If on the central atom there are lone pairs of electrons (also called unshared electrons) or electrons that are not involved in bonding the molecule will be polar (regardless of the bonds). The overall pull is uneven.
Trigonal pyramidal and bent shaped molecules will always be polar molecules.

Nonpolar Molecule (not the same as a nonpolar bond)

If on the central atom there are NO lone pairs of electrons (also called unshared electrons) the molecule will be nonpolar (regardless of the bonds). The overall pull is even.

What is the wave mechanical model?

our most current model of the structure of an atom

What is an orbital?

a probability distribution map of a region where the electron is likely to be found 90% of the time

What are 2 key observations that lead to the development of the wave mechanical model of the atom?

1. The path of an electron cannot be determined
2. an electron behaves both as a particle and a wave

What is the Pauli Exclusion Principle?

electrons in the same orbital have to have different spins

when describing an orbital what does the designations s,p,d, or f tell you?

the shape of an orbital

As the value of n increases what also increases?

the energy level, the distance from the nucleus, and the number of sublevels

How many orbitals does each sublevel have?

the s sublevel has 1 orbital, the p sublevel has 3 orbitals, the d sublevel has 5 orbitals, the f sublevel has 7 orbitals

what is the maximum number of electrons that each sublevel can hold?

the s sublevel can hold 2 electrons, the p sublevel can hold 6 electrons, the d sublevel can hold 10 electrons, and the f sublevel can hold 14 electrons

when describing the electrons in an orbital, we use arrows pointing up and down to indicate what property?

spin

what is the max number of electrons that can be found in any given orbital?

2 electrons

How many sublevels are present in any given energy level

the number of sublevels in any given energy level is equal to n (principle energy level)

How do electrons fill orbitals?

Electron fill lower energy levels before higher ones, then within an energy level they fill each orbital before pairing.

Charles' Law Equation

Gay-Lussac's Law Equation

Boyle's Law Equation

Boyle's Law Graph