Chem 3-4 (A) Exam chp 8-16

based on the review ms windham gave

four indicators of a reaction

evolution of gas, production of heat/light, unexpected color change, formation of a precipitate

indicators

evidence for a reaction

driving forces

why a reaction has occured

driving forces for reactions

formation of a solid, formation of water, transfer of electrons, formation of a gas

what is the general form of equations

reactants -\> products

Law of Conservation of Mass

Matter is neither created nor destroyed

equation symbol for solid

(s)

equation symbol for gas

(g)

equation symbol for liquid

(l)

equation symbol for aqueous solution

(aq)

symbol for 'forms, produces'

-\>

symbol for heat

triangle

what are 3 types of chemical equations

word equation, skeleton equation, balanced equation

word equation

describes rxn in words

skeleton equation

1st step - just includes formulas but no coefficients

balanced equation

final goal, obeys law of conservation of mass

what is the goal of a balanced equation

to show correct formulas and symbols for each element or compound.

dissociation

in water, anions and cations are separated from each other and the solution conducts electricity

electrolytes

substances whose aqueous solutions conduct electricity

solubility rules

a reference used to determine whether an ionic compound will dissociate in water.

types of chemical reactions

synthesis, decomposition, single replacement, double replacement, combustion

precipitation reactions

reactions that forms solids

acid-base reactions

reactions between acid and base usually forming water and salt

synthesis (or combination)

two elements/ compounds combine to form 2 product

decomposition

1 compound breaks up into elements or smaller compounds. requires endothermic energy

single replacement

has an element and a compound as reactants

combustion

oxygen is a reactant and energy is released (exothermic) often. the reactants are a hydrocarbon and oxygen. products are water and carbon dioxide

oxidation- reduction reactions

reactions involving the transfer of electrons aka redox

representative particles

subunits of a substance. includes atoms, ions, formula units, or molecules

what is used for single elemental units with charges

ions

what is used for ionic compound units

formula units

what is used for molecular compound units

molecules

what is used for single elemental units

atoms

is NaCl a atom, ion, formula unit, or molecule

formula unit

1 mole is equal to

6.02 x 10^23 molecules

What is Avogadro's number?

6.02 x 10^23

Stoichiometry

the part of chem that describes relative amounts of substances in chemical reactions

what are the steps for stoichiometry

write the given info

convert to moles

use a "mole ratio" between the given and the unknown

convert to the desired unit

formula for percent yield

actual/theoretical x 100%

thermodynamics

the study of energy

energy

the ability to do work or produce heat

potential energy

stored energy

kinetic energy

energy of motion

what is also known as the first law of thermidynamics

the law of conservation of energy

temperature

a measure of the kinetic energu of the componenents of a substance

heat

a flow of energy due to a temperature difference

exothermic

releases heat energy

endothermic

absorbs heat energy

calorie

amount of energy needed to raise the temperature of one gram of water by 1 degree C joule

4.184 J equal

1 Cal

1 cal \= 1 kcal\=

1000 cal

heat capacity

the amount of heat required to raise the temp of an object or substance a given amount

q \=

mc∆T

change in enthalpy

the amount of heat exchanged under constant pressure

Frequency

the number of complete wavelengths that pass a point in a given time

Wavelength

the distance from the peak of one light or sound wave to the peak of the next.

continuous spectrum

white light contains all wavelengths

line spectrum

chararcteristic of a certian element; certain wavelengths based on energy change of elecetrons

ground state

minimum energy of an atom

excited states

energy levels higher than the ground state

energy level

general region where an electron may be

principle energy levels

correspond to row number 1-7

4 types of sublevels

s, p, d, f

s

1 orbital, 2 elements

p

3 orbitals, 6 elements

d

5 orbitals, 10 elements

f

7 orbitals, 14 elements

oribital diagram

shows the location of each individal electron

what do the arrows and lines represent in an orbital diagram

arrows-electrons and lines- orbitals

Aufbau Principle

electrons fill orbitals of lowest energy first

Pauli Exclusion Principle

An orbital can hold a maximum of 2 electrons and electrons must have opposite spins

hund's rule

electrons spread out to full orbitals of equal energy before pairing up

in which group does each element have a total of four elements in the outermost principal energy level

14 (IVA)

Given an atom with the electron configuration 1s2.2s2.2p3, how many orbitals are completely filled

2

what is the total number of valence electrons in an atom with the electron configuration 1s2 2s2 2p6 3s2 3p3

5

what is the electron configuration for Na+1

1s2 2s2 2p6

How many electrons can each orbital hold?

2 electrons

which sublevel has 3 different orbitals

p

atomic radius

half the distance between nuclei of two like atoms. describes the size of the atom

increases down a group

decreases across a period

ionization energy

the energy required to remove an electron from an atom

decreases down a group

increases across a period

list Na, Cl, P, and Mg in order of increasing atomic radius

Cl, P, Mg, Na

list Na, Cl, P, and Mg in order of increasing ionization energy

Na, Mg, P, Cl

electron dot diagram

shows only the valence electrons (corresponds to column number)

what do the dots represent

valence electrons

What does the element symbol represent?

Nucleus and inner electrons

octet rule

atoms lose, gain or share electrons in order to acquire a full set of eight valence electrons

Ionic bonds form between

metals and nonmetals

covalent bonds form between

two nonmetals

ionic compounds are also known as

salts

molecular compounds

covalent bound compounds

Electronegativity

ability of an atom to attract electrons during bonding.

increases across a period

decreases down a group