chem exam 1

chapters 1-5

matter

has mass & takes up space

substance

specific type of matter

states

solid, liquid, gas

scales

atomic (small) & macroscopic (large)

solid

close together & ordered arrangement of atoms, strong

liquid

disordered arrangement, but interacting atoms, some strength

gas

far apart and no interaction of atoms, no strength

energy

-capability to do work

-moving an object against an opposing force

-can be kinetic or potential energy

energy of motion

more motion = more energy

temperature

measure of average KE of particles. higher temp, higher KE

heat

moves from high to low

potential energy

- stored energy, through position or composition

- the more unstable, the higher the PE

-reactions go towards the most stable state

difference

heat energy released when fuel (high PE) is burned

PE & food

- carbs & fats, high PE

- products of metabolism low PE

- energy is released to power metabolism

metric system

used in medicine and science

SI system

international unit

meter (m)

distance, length

gram (g)

mass, weight

liter (L)

volume

second (s)

time

1mL

1cm³

sig figs

- “guess” one place value beyond what can be read

- record all certain digits, assume uncertain

placeholder zeros

-aren’t significant!

-zeros in a decimal before the first integer

- large numbers with many zeros but no decimals

exact numbers

- obtained by counting

- whole numbers

- defined quantities

- no uncertainty or sig figs

round to

- the smallest amount of sig figs in an equation

- at the end!

conversion factors

1. identify given & asked for units

2. identify conversion between given & asked

3. express conversion a two conversion factors

4. multiply given by conversion factor

5. solve & round

density

- d = m/V

- units: g/mL, g/cm³

specific gravity

- density of substance/density of water!!

- important for diagnosis kidney function conditions (low-over hydrated, high-dehydrated)

- density of water is 1.000g/mL

normal specific gravity

1.002-1.030

dosage

mg drug/kg body weight

q.d

once a day

q.i.d

4x a day

b.i.d

2x a day

fahrenheit

- relative, uses + & -

- US only

- NOT for medicine

celsius

- worldwide!

- relative, uses + & -

normal body temp

37C, 98F

boiling temp

100C, 212F

freezing temp

0C, 32F

conversion between C &F

-C = (F-32)/1.8

-F = 1.8C + 32

atoms

- sphere

- protons & neutrons = nucleus

- electrons surround nucleus, fast & random

proton

positive

neutron

neutral

electron

negative

atom mass

- from protons and neutrons

- electrons have negligible mass, determine volume

charge

protons & electons

atomic number

number of protons

atomic mass

avg mass of isotopes of the same element

atomic symbol

uppercase letter then lowercase letter

isotopes

- same protons & electrons, diff neutrons

- identified by mass #

isotope nuclear symbol

- mass # superscript

- atomic # subscript

groups of elements

exhibit similar properties

groups 1A-8A

main!

1A

alkali metals

2A

alkaline earth metals

7A

halogens

8A

noble gasses (most stable)

groups 1B-8B

-transition metals

-inner transition metals

periods

rows

metals, nonmetals, metalloids

- bold diagonal steps separate left metals from nonmetals on right

-Al is a metal!

metals

- exist as a solid at room temp, except Hg

- shiny

- good conductors

- flexible

nonmetals

- dull

- exist as solids, liquids, & gasses

- poor conductors

metalloids

properties in between metals and nonmetals

electron arrangement

determines physical and chemical properties

quantum mechanics

- electrons have certain allowed energy levels

- n = symbol for levels

- the larger n is, the smaller the difference between energy levels is

- n = 2n²

2 valence electrons

level 1

8 valence electrons

levels 2 & 3

valence electrons

- electrons in the outermost shell

- does not equal total electrons

periodicity

repeating patterns found in the periodic table

octet rule

- 8 is very stable

- electrons want a filled valence shell

ionic compounds

- salts!

- charged ions

- form when metal atoms transfer electrons to nonmetal atoms

- held together by strong opposite charges

- net charge

-structure determines function

- compounds have different properties than their elements

cation

- from metal losing electrons

- positive charge in superscript

anion

- negative charge in superscript

- from nonmetals gaining electrons

ionic bond

strong electrostatic attraction between oppositely charged ions

ions

change in electrons

ionic compound ratio

reflected in subscript

electrolytes

-ions dissolved in water conduct electricity

- super important in the body

cations 1A, 2A, 3A

- lose all valence electrons

- name of cation, same as element

- electron arrangement of noble gas before it

- Be & B exception

anions 5A, 6A, 7A

- nonmetals

- gain electrons to fill shell

- same electron arrangement as noble gas after

- name is element name w/ -ide ending

naming ionic compounds

-cation name + anion name

-no need for subscripts

writing formula unit of a ionic compound

- list cation and anion symbol w/ no charges

- make sure sum of charges is 0

- simplify when possible!

4A transition metals

- don’t always lose all their valence electrons

- name w/ roman numeral

- some fixed ions, silver, zinc, cadmium

silver ion

Ag⁺

zinc ion

Zn²⁺

cadmium ion

Cd²⁺

2 ways to figure out transition metal charge

- crisscross method

- math

heavy metals

- mainly Pb (lead II & IV) & Hg (mercury I & II)

- Pb²⁺ & Hg₂²⁺ are poisonous

ionic compounds in products

- calamine lotion → zinc oxide & iron(III) oxide

- many toothpastes contain fluoride

polyatomic ions

- come from molecules

- contain 1+ covalent bond

- unequal amt of protons & electrons

- unique name, formula, 7 charge

- few cations

cation polyatomic ions

- NH₄⁺ ammonium

- H₃O⁺ hydronium

writing formula unit for polyatomic ions

- same as monoatomic

- can use parenthesis on polyatomic ion if subscript is needed

naming polyatomic ions

- name cation

- name anion (use name of polyatomic)

- be careful w/ suffixes!

polyatomic ions in products

- bleach

- preservatives

- tooth enamel

covalent compounds

- made of identical molecules, composed of 2+ nonmetal atoms joined by covalent bonds

- nonmetal ions joined

• Si & B (metalloids) can too !

- includes many cellular compounds such as proteins, carbs, DNA, & RNA

- diff shapes & sizes

diatomic elements

- H₂, N₂, O₂, F₂, Cl₂, Br₂, I₂

• (H7 on periodic table)

- never by themselves, always paired up w/ another element

the covalent bond

- 2 hydrogen atoms → H₂

- valence electrons shared

- has noble gas electron arrangement

- more stable atoms

molecular formulas

- covalent molecule

- specifies # of each type of atom in each molecule as subscripts, usually alphabetical

- differs from ionic formulas

- DON’T simplify subscripts

• glucose C₆H₁₂O₆

naming simple binary compounds

- name first element, then second w/ -ide

- insert prefixes indicating # of each atom type

- mono- only for second element

one

mono

two

di

three

tri