CHEM 1001 - Quiz 1

Chemistry

The study of matter and its properties.

Matter

Anything that has mass and occupies space - characterized by its physical and chemical properties.

3 States of Matter

Solid (s) - defined volume, particles are close together, retains its shape.

Liquid (l) - defined volume, particles are close together but they move around, adopt the shape of their container.

Gas (g) - has no definite volume, adopts the full volume of the container, particles are in constant random motion.

Pure Substance

Single component, constant composition (such as water, iron, glucose or table salt). Elements and Compounds.

Mixture

2+ more components, varying composition (such as sand, air, iron ore, tap water or bronze).

Elements

Pure substance that cannot be broken down via chemical reaction (such as CU (copper)).

Compounds

Composed of 2+ different elements (such as H2O or NaCl).

Scientific Notation

Used to describe very large or very small numbers.

Move decimal point back to the first number, count and put it x 10^number moved

Positive exponent = very large, negative exponent = very small.

Metric Units

Standard set of units in scientific communication

Length = meters (m)

Mass - grams (g)

Time = seconds (s)

Volume - liters (L)

Metric Prefixes

Indicates whether an amount is larger or smaller than the bass unit.

Kilo (k)

1kg = 1000g

Centi (c)

100cm = 1m or 1cm = 0.01m

Milli (m)

1000ml = 1L or 1ml = 0.001L

Micro (μ)

10^6μg = 1g - 1 million

Nano (n)

10^9nm = 1m - 1 billion

Temperature

Celsius - many countries and science

Kelvin - chemist and engineers

Fahrenheit - United States

Temperature in Kelvin

= T in C + 273

Temperature in Celsius

= T in K - 273

Temperature in Fahrenheit

= 9/5 (T in C) + 32

Temperature in Celsius

= 5/9 (T in F - 32)

Elements

All are represented by a 1 or 2 letter code (elemental symbol) - capitalization matters.

Stair Step Line

Elements along the line = metalloids

Elements to the left = metals

Elements to the right = nonmetals

Metals

Shiny and conductive

Nonmetals

Not shiny and no conductive.

Metalloids

Intermediate properties

96% of the human body mass =

Carbon, hydrogen, oxygen, and nitrogen = building block of elements

H & O = water

C, H, & O = carbohydrates and lipids

C, H, O, & N = proteins and nucleic acids (DNA)

Macronutrients = 0.1-2.7% by mass

Essential in the daily diet (100+mg per day)

K, Na, Cl = body/brain or nerve fluids

Mg, S = muscles

Ca, P = bones

P = DNA

Micronutrients = ,0.1% by mass (,15mg or less per day)

Fe = red blood cells

Zn = liver, kidney and enzymes

I = thyroid function

Atomic Structure: 3 Subatomic Particels

• Protons (p^+) = +1 (positively charged), mass(kg) = 1.67x10^-27

• Neutron (n^o) = 0 (charge of zero), mass = 1.67x10^-27

• Electron (e^-) = -1 (negatively charged), mass = 9.11x10^-31

  • Most of an atom’s mass is in the nucleus (p+n)

  • Most of an atom’s volume comes from the electrons (outside of the nucleus)

Every atom of a given element has the same number of protons

Atoms are electrically neutral (uncharged)

Number of Protons

= atomic number (Z) and number of electrons

Top Number

= atomic number = number of protons

Nuclide Number

Periodic Table Organization

Columns = groups

Rows = periods

Two taller columns on each side = main group elements

Middle = transition metals

Bottom separate rows - top = lanthanides, bottom = actinides

Elements in the same column (group) have similar properties

Group 1

Alkali metals (except hydrogen)

Group 2

Alkaline earth metals

Group 17

Halogens

Group 18

Noble gases

Electron Configuration

Occupy discrete energy levels (orbitals).

4 Types of Orbitals

S = Sphere - set of 1 orbital

P = Infinity circle - sets of 3 orbitals (3 axis)

D = Clover leaf (4 leaf) - sets of 5 orbitals

F = Double clover leaf - sets of 7 orbitals

Orbitals can hold a maximum of 2 electrons

S: 2 total electrons

P: 6 total

D: 10 total

F: 14 total

Periodic Table Blocks

First two rows = S Block

Last 6 = P Block

Middle = D Block

Bottom = F Block

Core Electrons vs. Valence Electrons

• Valence = electrons in the highest s and p shells

• Core = electrons in the lower s and p shells

Lewis Dot Structures

Dots in the top, bottom, left, and right of the element’s symbol. Dots = valence electrons.

Chemical Bond

The joining of 2 atoms in a stable arrangement (noble gas configuration). Atoms gain, lose, or share electrons to reach that noble gas configuration (8 valence electrons). Either ionic or covalent bonding.

Ionic Bonding

When electrons are transferred from one atom to another.

• Metal + nonmetal

Covalent Bonding

When electrons are shared between atoms.

• 2 nonmetals or metaloid and nonmetal.

Ions are Charged Species

Cation: positively charged = more protons than electrons - formed by metals.

Anions: negatively charged = more electrons than protons - formed by nonmetals.

Main Group Elements Form Ions to Achieve Noble Gas Configuration

Left loses electrons to get a positive charge.

Right gain electrons to get a negative charge.

Middle can gain or lose electrons (covalent).

Ions of Life - Na+ (sodium)

Regulates blood pressure, blood volume, and helps maintain organ function.

Ions of Life - K+ (potassium)

Maintains fluid balance in cells, regulates nerve function and signals, and muscle contractions.

Ions of Life - Mg2+ (magnesium)

Nerve conduction and muscle contraction.

Ions of Life - Fe2+ (iron)

Oxygen transport in blood.

Ions of Life - Ca2+ (calcium)

Found in bones and teeth, nerve conduction and muscle contraction.

Ions of Life - Mn2+ (manganese)

Blood clotting.

Ions of Life - Cl- (chloride)

Fluid balance.

Ions and Ionic Compounds

Ions are charged (cations or anions)

Compounds (2 or more elements) electrically neutral.

Ionic Compounds - the charge of all ions have to cancel.

How to determine the chemical formula of an ionic compounds (sodium and chlorine)

• 1. Identify the cation and anion. 

  • Sodium (Na^+), Chlorine (Cl^-)

• 2. How many of each are needed for an overall charge of zero. 

  • One of each

• 3. Write the cation first, than the anion, with numbers greater than 2 as subscripts

  • NaCl = chemical formula

Naming Ionic Compounds

All ionic compounds have 2 word names (cation in name than anion name)

• Sodium (cation) chloride (anion)

Naming Cations

Type I: main group metals and Ag+, Zn2+, and Al3+

• Cation name is just the name of the metal.

Type II: transition metal sna d Pb and Sn.

• Cation name is the metal name (charge in roman numerals)

  • FeCl₂ = Fe²+Cl^- = Iron (II)

• Polyatomic = Ion name

Naming Anions

Main group nonmetals = root+ide

• Element:            Root:

     F                    fluor-

    Cl                   chlor-

    Br                   brom-

     I                     iod-

     H                    hydr-

     N                    nitr-

     O                    ox-

     S                     sulf-

     P                     phosph-

Polyatomic = ion name

Covalent Compounds

Formed when you have a metal + nonmetal or when you have a polyatomic ion in your compound.

Lewis Structures - How to draw (PCl₃)

• 1. Count up the valence electrons

  • P = 5

  • Cl = 3(7) = 21

  • Total = 26 e^-

• 2. Draw the skeleton of your structure

  • Cl - P - Cl

      Cl

• Unique atom goes in the middle

• 3. Add the remaining electrons to outer atoms first, than inner atoms

  • Cl - P - Cl

       Cl

• Each line represents 2 electrons, so 6 are used through the lines

• Add 3 (6) to each Cl and 1 (2) to P

• 4. Check the octet rule and adjust if needed

  • Octet Rule: most electrons want 8 electrons

  • If you need to adjust, make lone pairs into shared pairs (add a second line to connect two of the atoms)

  • Exceptions to octet rule: Hydrogen only wants 2 electrons

Naming Covalent Compounds

• CO_2 = Carbon Dioxide

• Prefix + 1st element = first word

• Prefix + 2nd element + ide = second word

• First word: 2 or more you use the prefix

• Second word: always use the prefix

  • # of atoms: 

    • 1 = mono - 

    • 2 = di -

    • 3 = tri - 

    • 4 = tetra - 

    • 5 = penta - 

    • 6 = hexa - 

    • 7 = hepta - 

    • 8 = octa - 

    • 9 = nona - 

    • 10 = deca - 

Gases

Compounds in the atmosphere of earth are generally gases.

• Gas particles are in constant random motion

• When they collide with a container surface, they exert a pressure.

  • Pressure = force/unit area

Gas Units

• Psi = pounds per square inch = tires

• InHg = inches of mercury = weather

• Atm, torr = atmosphere = chemistry

• mmHg = millimeters of mercury = blood pressure

  • 1atm = 14.7psi = 760mmHg = 760torr

  • Atm - standard chemistry unit = atmospheric pressure at sea level on earth

Ideal Gas Law

The pressure volume, temperature, and the amount of gas are all related to each other.

PV = nRT

P = pressure (atm)

V = volume (L)

n = number of moles of gas (mol)

R = ideal gas constant (0.0821L*atm/mol*K)

T = Temperature (K)

PV = nRT - Relationships

• V and T Relationship 

  • When you increase the temperature of air particles, you increase their speed = increase in volume (assuming pressure and amount of gas are constant). 

  • Example = hot air balloon

  • If you lower the temperature the volume also decreases

• P and T Relationship

  • If you increase the pressure you increase the temperature (assuming the volume and amount of gas are constant)

  • Example = pressure cooker

  • If you lower the pressure the temperature also decreases

• n and V relationship

  • If you increase the amount of gas the volume increases

  • Example = inflating a balloon

• P and V Relationship

  • At sea level/ground you have a tube of toothpaste - toothpaste and ground pressure are the same. As you rise in the air, the toothpaste has the same pressure but the airplane's pressure is less pressurized = more pressure in the toothpaste compared to the airplane’s pressure. 

  • As the pressure increases, the volume must decrease

  • Example = exploding products after airplane