CHAPS Unit 7: Chemical Formulas & Equations

What is a chemical symbol?

abbreviation for the element name

How many letters is a chemical symbol?

1 or 2

What is true of the first letter in a chemical symbol?

capitalized

What is a chemical formula?

representation of the elements that make up a compound

What is a compound?

combination of 2+ elements chemically combined in a definite ratio by mass

What information does a chemical formula provide?

elements and number of elements

What is a subscript?

number of each element present in the compound

What is a superscript?

charge of an ion

What is a coefficient?

number of present units

What is an empirical formula?

representation of simplest integer ratio between atoms in a compound

What is a molecular formula?

actual ratio of elements in a compound

What is the law of definite composition?

all compounds have the same percent composition

What is the law of multiple proportions?

some compounds are formed by the same 2 elements where the mass of one element is constant, while the other varies (but 2nd’s mass is in a ratio with 1st’s weight)

What is an ionic bond?

bond formed between metal and nonmetal

What is the oxidation number?

number of electrons lost, shared, or gained by an an element

What must the sum of the oxidation numbers be in a compound?

0

what comes first in the names of an ionic compound?

metal

what happens to the nonmetal in the name of an ionic compound?

last syllable replaced with ‘ide’

What is a polyatomic ion?

ion made up of more than 1 atom, carrying its own name

What happens when a subscript is applied to a polyatomic ion in an ionic compound?

placed outside parentheses

What are oxyanions?

series of anions with atom of an element and different number of oxygen atoms

What is the suffix of the oxyanion with less oxygen in an oxyanion series? (2 in series)

ite

What is the suffix of the oxyanion with more oxygen in an oxyanion series? (2 in series)

ate

What is the prefix for the oxyanion with lowest amount of oxygen in an oxyanion series (2+ in series)

hypo

What is the prefix for the oxyanion with highest amount of oxygen in an oxyanion series (2+ in series)

per

What is the criss-cross method

the charges become to subscripts of the other atom and then reduce

What is a binary ionic compound (type II)?

a compounds with a metal that can form more than one type of cation

How do you indicate the charge of the cation in binary ionic compounds?

roman numbers

When is the roman numeral needed?

more than 1 ionic compound forms between given pair of elements

When is the stock system used?

when element has more than 1 oxidation numner

What type of element is the stock system usually used for?

transition metals

What is the traditional system?

old system of nomenclature used for metals that form only 2 ions

What is the suffix for the lower charged atom in the traditional system?

ous

What is the suffix for the lower charged atom in the traditional system?

ic

What is the latin root for chromium (Cr)?

chrom

What is the latin root for manganese (Mn)?

mangan

What is the latin root for iron (Fe)?

ferr

What is the latin root for cobalt (Co)?

cobalt

What is the latin root for copper (Cu)?

cupr

What is the latin root for mercury (Hg)?

mercur

What is the latin root for tin (Sn)?

stann

What is the latin root for lead (Pb)?

plumb

What elements DON’T need a roman numeral?

group 1, group 2, aluminum (+3), silver (+1), zinc (+2)

What are the oxidation states of hydrogen?

+1, -1

What is a molecular compound?

compound made up of molecules

What is a molecule?

compound that contains covalent bond

What is a covalent bond?

bond between 2 nonmetals that share electrons

What should be the order when writing molecular formulas?

less electronegative nonmetal first

What is the prefix for one atom in binary covalent compounds?

mono

What is the prefix for two atoms in binary covalent compounds?

di

What is the prefix for three atoms in binary covalent compounds?

tri

What is the prefix for 4 atoms in binary covalent compounds?

tetra

What is the prefix for 5 atoms in binary covalent compounds?

penta

What is the prefix for 6 atoms in binary covalent compounds?

hexa

What is the prefix for 7 atoms in binary covalent compounds?

hepta

What is the prefix for 8 atoms in binary covalent compounds?

octa

What is the prefix for 9 atoms in binary covalent compounds?

nona

What is the prefix for 10 atoms in binary covalent compounds?

deca

What happens if the prefix ends with a or o and the element begins with a vowel in covalent compounds?

drop last vowel of prefix

When should you not use a prefix in molecular nomenclature?

first element has only 1 atom

What is the suffix for the element with the higher electronegativity in molecular nomenclature?

ide

When are prefixes not needed?

molecular compounds with hydrogen and 1 other element (neutral substances)

Do you reduce in molecular compounds?

no

Do you crisscross in molecular compounds, and why?

no, because oxidation numbers are just apparent charges

What is a binary compound?

compound made up of 2 elements

What is a ternary compound?

compound made up of 3+ elements, usually containing polyatomic

What is an acid?

water solution of certain hydrogen compounds

What do binary acids contain?

hydrogen and 1 other elements (anion doesn’t have oxygen)

How is sulfur an exception in binary acid nomenclature?

don’t stop ending

What is the prefix for binary acids?

hydro

What is the suffix for binary acids?

drop ending of NM, add ic + acid

What must you add after the formula for an acid?

(aq)

What is hydrogen’s oxidation state in acids?

+1

What do ternary acids contain?

hydrogen and a polyatomic ion, anion will have oxygen

What is the prefix for ternary acids?

no prefix

What is the suffix for ternary acids if the polyatomic ion ends in ‘ate’?

ic + acid

What is the suffix for ternary acids if the polyatomic ion ends in ‘ite’?

ous + acid

What is true of the polyatomic ions in ternary acid formula writing?

no parentheses

What are reactants?

substances that exist before chemical change or reaction

What are products?

new substances formed during chemical reaction

What is an endothermic reaction?

process that requires energy for reaction that absorbs energy

What is energy in an endothermic reaction?

reactant

What is an exothermic reaction?

chemical reaction that releases energy

What is energy in an exothermic reaction?

product

What does + mean in chemical reactions?

separation of 2 reactants or products

What does → mean in chemical reactions?

produces

What does (s) mean in chemical reactions?

solid

What does (l) mean in chemical reactions?

liquid

What does (g) mean in chemical reactions?

gas

What does (aq) mean in chemical reactions?

aqueous solution

What does ∆ mean in chemical reactions?

addition of heat

What must you balance equations with?

positive integers that are coefficients

What is a molecular equation?

equation that shows complete chemical formula of reactants and products

What is a complete ionic equation?

equation in which all soluble strong electrolytes are shown as ions

What are strong soluble electrolytes?

strong acids, strong bases, soluble ionic compounds

What are spectator ions?

ions that are identical on both sides of complete ionic equation and play no direct role in reaction

What is a net ionic equation?

ionic equation where spectator ions are omitted

How do you write net ionic equations?

write balance molecular equation, rewrite equation to show ions that form in solution, and cancel spectator ions

What is synthesis?

combination reaction; reaction where 2+ reactants combine and form a single product

What is decomposition?

reaction where single reactant is broken into 2+ simpler substances