ch. 9- chemical bonds Flashcards
Compound
A substance made of two or more elements chemically combined in a specific ratio
Chemical formula
Tells what elements a compound contains and the exact number of the atoms of those elements
Coefficient
Represents the # of units of each substance
Subscripts
Represents the # of atoms in a molecule of a particular element
Superscript
Represents oxidation # or how many electrons have been gained or lost
Chemical bond
Force that holds together the atoms in a substance
Atoms form compounds to become _______
Chemically stable
Ion
Positively/ negatively charged atom
Cation
+ charged atom
Anion
- charged atom
Ionic bond
The attraction between ions with opposite charges
- electrons are transferred
- b/w metal and nonmetal
Covalent bond
A chemical bond formed when 2 atoms share electrons
- happens b/w a nonmetal and nonmetal
Nonpolar
A covalent bond in which electrons are shared equally
Polar
A covalent bond in which electrons are shared unequally
Oxidation #
+/- # which indicates how many electrons an element has gained or lost when bonding
- also known as the charge
Binary ionic compound
Compound composed of 2 elements
- have charge of 0
Polyatomic ion
A +/- charged group of covalently bonded ions
Transition metals can have many ______
Charges
Hydrate
A compound that has water chemically attatched to its ions and written into its chemical formula
Binary covalent compounds
Form from the combo. of 2 nonmetals (or nonmetal and metalloid)
- do not involve ions
Chemcial equation
A way to describe a chemical reaction using symbols instead of words
What does a chemical equation identify (3 thing):
- identities of molecules in the reaction
- elements that make up the molecules
- whether the molecules are products or reactants
Chemical reaction
One or more reactants are changed to new substances through a rearrangement of the molecular or ionic structures
Law of conservation of mass
During reactions matter is neither created or destroyed
______ are used to balance equations
Coefficients
What are the steps to BCE (4)?
- Write a chemical equation for the reaction
- Count the atoms in the reactants and products
- Choose coeffcients that balance the equation
- Recheck the #’s of each atoms on both sides and change coefficients if needed
What are you never supposed to do when BCE?
Change subscripts
Synthesis reaction
2 or more substances combine to form a new substance
- A + B—> AB
One substance breaks down or decomposes into 2 or more simpler substances
- AB—> A + B
Single displacement
One element replaces another in a compound
- A + BC—> B + AC
Double displacement
- results in a precipitate (water/ gas)
- when a + ion of one compound swaps with another + ion of another compound
- AB +CD—> AD + CB
Exothermic
Energy is released in the form of heat
Endothermic
Heat energy is absorbed
Catalyst
Speeds up a chemical reaction
Inhibitor
Prevents/slows down a chemical reaction
