CHEM 1001 MIDTERM STUDYY

What are the properties of a solid

Definite shape and definite volume

What are the properties of a liquid

Definite volume and takes the shape of its container

What are the properties of a gas

No definite shape and no definite volume

What is a physical change

A change in form or state without changing chemical identity

Why is melting ice a physical change

It remains H2O after melting

What is a chemical change

A change that produces a different substance

How is matter classified

Matter can be a pure substance or mixture / pure substances are elements or compounds

What is the difference between homogeneous and heterogeneous mixtures

Homogeneous is uniform throughout / heterogeneous is not uniform throughout

How many centimeters are in 1 inch

2.54 cm

What determines whether an object floats or sinks in water

Less dense than water floats / more dense than water sinks

What is proper scientific notation

A value from 1 to less than 10 multiplied by a power of 10

How does decimal movement affect scientific notation

Move decimal left for positive exponent / right for negative exponent / 0.005 = 5.0 x 10^-3

What is potential energy

Stored energy based on position or chemical composition

What is kinetic energy

Energy of motion

What energy conversions should you know

1 kJ = 1000 J / 1 kcal = 1000 cal / 1 kcal is about 4.18 kJ

What is the difference between exothermic and endothermic

Exothermic releases energy and is negative / endothermic absorbs energy and is positive

What are intermolecular forces

Attractions between molecules

What are dispersion forces

Weak attractions between nonpolar molecules caused by temporary dipoles

What are dipole-dipole forces

Attractions between polar molecules

What is hydrogen bonding

A strong molecular attraction when H is bonded to F O or N

What happens when an alkane chain gets longer

Intermolecular forces get stronger and boiling or melting point usually increases

What are the six phase changes

Melting solid to liquid / freezing liquid to solid / vaporization liquid to gas / condensation gas to liquid / sublimation solid to gas / deposition gas to solid

Which phase changes absorb or release heat

Melting vaporization sublimation are endothermic / freezing condensation deposition are exothermic

What specific heat formulas should you know

q = m c deltaT / deltaT = final temperature - initial temperature / water c = 4.184 J per g C

What are heat of fusion and heat of vaporization

Fusion is heat to melt 1 g / vaporization is heat to turn 1 g liquid into gas

What do plateaus and slopes mean on a heating curve

Plateau means phase change at constant temperature / slope means temperature change

What are groups and periods on the periodic table

Groups are vertical columns / periods are horizontal rows

Where are metals nonmetals and metalloids on the periodic table

Metals mainly left / nonmetals mainly right / metalloids along the zigzag line

What are the s p d and f blocks

Main group = s and p / transition = d / inner transition = f

What do subscripts in a chemical formula tell you

They show the number of atoms / C6H12O6 has 6 C / 12 H / 6 O

What is atomic number

The number of protons

How are mass number neutrons protons and electrons related

Mass number = protons + neutrons / neutrons = mass number - atomic number / neutral electrons = protons

What are the charges and locations of subatomic particles

Proton +1 nucleus / neutron 0 nucleus / electron -1 outside nucleus

What is electron configuration

The arrangement of electrons in energy levels and sublevels

What is the electron configuration of potassium

1s2 2s2 2p6 3s2 3p6 4s1

How many electrons can each sublevel hold

s = 2 / p = 6 / d = 10 / f = 14

What are valence electrons and core electrons

Valence electrons are outer and react / core electrons are inner and usually do not react

Why are noble gases stable and what do alkali metals do

Noble gases have filled outer levels / alkali metals lose one electron and form +1 ions

Why do elements in the same group have similar properties

They have similar outer electron configurations

What atomic size trend do the Chapter 3 slides give

Atomic size increases down a group and decreases left to right

What are the ionization energy and metallic character trends

Ionization energy decreases down and increases left to right / metallic character increases down and decreases left to right

What is an isotope

Atoms of the same element with the same atomic number but different mass numbers

What is a radioisotope

An isotope that emits radiation

What is an alpha particle

A helium nucleus with mass number 4 and charge +2

What is a beta-minus particle

A high energy electron with mass number 0 and charge -1

What is a positron

A particle with mass number 0 and charge +1

What is a gamma ray

Pure energy with mass number 0 and charge 0

How do alpha beta and gamma compare in penetration and shielding

Alpha is least and stopped by paper / beta needs heavier shielding / gamma is greatest and needs lead or concrete

What must balance in a nuclear equation

Total mass numbers and total atomic numbers must be equal on both sides

What happens in alpha decay

Mass number decreases by 4 / atomic number decreases by 2

What happens in beta-minus decay

Mass number stays the same / atomic number increases by 1

What happens in positron and gamma emission

Positron keeps mass same and lowers atomic number by 1 / gamma changes neither

What is nuclear fission

A large nucleus splits into smaller nuclei and releases large amounts of energy

What is nuclear fusion

Small nuclei combine into a larger nucleus and release large amounts of energy

What is half-life and how do you solve half-life problems

Half-life is time to lose half / number of half-lives = elapsed time divided by half-life / halve amount each time

What is a cation

A positive ion formed by losing electrons / it has fewer electrons than protons

What is an anion

A negative ion formed by gaining electrons / it has more electrons than protons

What common main-group ion charges should you know

Group 1 +1 / Group 2 +2 / Group 13 +3 / Group 15 -3 / Group 16 -2 / Group 17 -1

What is an ionic bond

Electron transfer between a metal and a nonmetal

What is a covalent bond

Sharing of electrons between nonmetal atoms

How do you write a correct ionic formula

Use the lowest whole-number subscripts so total positive and negative charge equals zero

How do you name a basic ionic compound

Name the cation first / name the monatomic anion second with an -ide ending

How are variable-charge metals named

Use a Roman numeral / FeCl2 = iron(II) chloride / FeCl3 = iron(III) chloride

What is a polyatomic ion

A group of covalently bonded atoms with an overall ionic charge

What important polyatomic ions should you know part 1

OH- hydroxide / NH4+ ammonium / NO3- nitrate / NO2- nitrite / CO3^2- carbonate / HCO3- bicarbonate

What important polyatomic ions should you know part 2

SO4^2- sulfate / SO3^2- sulfite / PO4^3- phosphate / PO3^3- phosphite / CN- cyanide / C2H3O2- acetate

How do -ate and -ite polyatomic ion names relate

-ite usually has one less oxygen than the related -ate ion

What covalent prefixes should you know

1 mono / 2 di / 3 tri / 4 tetra / 5 penta / 6 hexa / 7 hepta / 8 octa / 9 nona / 10 deca

How do you name a covalent compound

Name first nonmetal normally / second uses a prefix plus element root plus -ide

What covalent naming examples should you know

CO = carbon monoxide / CO2 = carbon dioxide / NCl3 = nitrogen trichloride / SF2 = sulfur difluoride

What do single double and triple covalent bonds mean

Single = 1 shared pair / double = 2 shared pairs / triple = 3 shared pairs / carbon commonly forms 4 bonds

What is the molecular shape of CH4

Tetrahedral

What is the molecular shape of PF3

Trigonal pyramidal

What is electronegativity

Ability to attract shared electrons / increases left to right / decreases down a group / fluorine is highest

How does electronegativity difference predict bond type

0.0 to 0.4 = nonpolar covalent / 0.5 to 1.8 = polar covalent / greater than 1.8 = ionic in the course rule

How do identical and different atoms affect bond polarity

Identical atoms make nonpolar bonds / different atoms may make polar bonds / larger difference means greater polarity

How can a molecule with polar bonds still be nonpolar

Bond dipoles can cancel because of the molecular arrangement

What molecular polarity examples should you know

CCl4 is nonpolar overall despite polar C-Cl bonds / H2O is polar / CH4 is nonpolar