CHEM MIDTERM TOPIC 2-FORMULAS AND EQUATIONS
Terms
undefined, object
copy deck
- diatomic molecules
-
molecules written with a subscript of 2 because they are elements that exist in nature as two identical atoms covalently bonded
-BrINClHOF - what kind of bond do diatomic molecules have?
- covalent
- qualitative info
- relates to things that canot be counted or measured
- quantitative info
- deals with things that can either be counted or measured
- empirical formulas
-
-include all types of compounds
-represents the simplest integer ratio in which atoms combine to form a compound - what do ionic substances form if they dont form units or molecules?
- ions in a compound
- how are ions in a compund written?
- in an empirical formula
- molecules
- units formed by covalently bonded substances
- molecular formula
- a multiple of the empircal foormula
- how do ions form a compound?
- negatively charged ions attract positively charged ions
- polyatomic ion
- a group of atoms covalently vonded together possessing a charge
- how do you form a bionary ionic compound formula?
-
the positively charged metal is placed first, and the negatively charged nonmetal comes second or at the end
-the negative ion is slightly changed from the element to end in -ide - what do you do if a binary compound contains two nonmetals rather than a metal and a nonmetal?
-
-it is a binary covalent compound
you put the element with the LOWEST electronegaviity first
-you use a prefix to tell how many of each element there are - prefixes for naming a binary covalent compound
-
1- mono
2- di
3- tri
4- tetra
5- penta
6- hexa
7- hepta
8- octo - endothermic processes
- processes that reuqire energy inorder to occur
- what happens to temp. during an endothermic reaction and why?
- the surrounding temp. is lowered bc the energy required is absorbed from the surroundings
- what does a endothermic process look like?
-
A+ energy--->B
or A+B+energy--->B+C - exothermic process
- process that releases thermal energy they it occurs
- what happens the temp during an exothermic reaction and why?
- the temp increases because energy is given off to the surrounding area
- what does an exothermic reaction look like?
- A+b--> C+ energy
- what has a a higher potential energy, exo or endothermic reactions?
- endothermic reactions have higher potential energy
- aqueos
- can be dissolved in water
- synthesis reaction
-
-when two or more reactions combine to form a sginel product
A+B--->AB - decomposition
-
-the reverse of syntehsis
-a single compound is broken down into two or more impler substances
AB---> A+B - single replacement
-
one element replaces another in a compound
-a metal replaces another metal
A+BC-->B + AC - how can a nonmetal replace a nonmetal?
- a nonmetal can replace a less active nonmetal (table j)
- double replacment
- AB+CD--->AD+BC
- how do you know if a double replacement will occur (3 ways
-
1. one of the products is a solid
2. one of the products is a gas
3. if a molecular substance such as water is formed - how do you determine an unknown reactant and product?
- figure out what would balance the equation
- how do you determine missing mass in equations??
- balance the mass on both sides of the equation