Chemistry 101 Ncsu Test 1

Front 1

Distinguish between an atom, molecule, element and compound

Back 1

Element- simplest form of a substance, one or more of a single type of atom

Molecule- two or more chemically bound atoms

Compound- two or more different types of atoms

Front 2

Difference between Law & Theory

Back 2

Scientific laws descibe observations, they don't explain them. Theories provide an explanation which incorporates facts, laws, inferences, & tested hypotheses

Front 3

Avogadro's Number Equals...

Back 3

One mole - which is the number of atoms or molecules present in a sample of an element or compund with a mass equal to its atomic or molecular mass expressed in grams

6.02 * 10^23

Front 4

What is Atomic Mass?

Back 4

The mass of one mol of each particular atom

Units in g/mol

1 mol N atoms = 14g
1mol Pb atoms = 207.2g

Front 5

Calculate the Mm of H2O

Back 5

(2*1 g/mol)+(1*16 g/mol) = 18g/mol

Front 6

Conversion Process

Back 6

Grams of a Substance ⇆ Moles of a Substance ⇆ Number of Particles

(150g of S_8 ⇆ 0.6 mol S_8 ⇆ 3.6*10^22 molecules of S_8)

Front 7

O2 = How many mol oxygen molecule?

How many mole of oxygen atom?

Back 7

1 mol oxygen molecule

2 mol oxygen atom

Front 8

Limiting Reactant

Back 8

The reactant which is used up completely in a reaction. The other is in excess.

Front 9

(A/Z) X ^n

What do A, Z, & n represent?

Back 9

(A)=Mass number - # of protons +# of neutrons

(Z)=Atomic number - # of protons (often omitted)

(n)=charge ( - or + )

Front 10

Isotope

Back 10

atoms that have the same number of protons (are the same element) but have different number of neutrons

Front 11

Cations

Back 11

ions with more protons than electrons

#p > #e

Na - e- → Na+

Front 12

Anions

Back 12

ions with less protons than electrons

#p < #e

Cl + e- → Cl-

Front 13

Element. List some examples

Back 13

A substance is composed of identical atoms. Gold, silver, oxygen, hydrogen, lead, chlorine, helium, iron, copper, fluorine, arsenic

Front 14

Compound. List some examples

Back 14

substance composed of two or more elements chemically combined. Water - H2O; Salt - NaCl; Sugar - C6H12O6; Ammonia - NH3

Front 15

Atomic Number: What are the atomic numbers of helium, hydrogen, carbon, oxygen?

Back 15

The number of protons in the nucleus of an atom of an element. Helium-2; carbon-6; hydrogen-1; oxygen-8

Front 16

Mass number

Back 16

The sum of protons plus neutrons n the nucleus of an atom

Front 17

Molecule

Back 17

A group of two or more atoms held together by chemical bonds

Front 18

Ion (provide examples)

Back 18

An atom or group of atoms which contains a positive or negative electrical charge (ex. Na+; Cl-; SO4^2-)

Front 19

Cation and Anion (provide examples)

Back 19

cation - positively charged ion (Na+; Fe+2; NH4+; Ag+); anion - negatively charged ion (Cl-; SO4-2; OH-; P-3)

Front 20

Valence electroncs

Back 20

The electrons found in the outermost energy level of an atom

Front 21

Oxidation number

Back 21

A number (positive or negative) representing the charge on an ion or atom involved in a chemical bond

Front 22

Three general rules for determining oxidation numbers

Back 22

1) Atoms of uncombined elements equal 0; 2) Hydrogen = +1 (in metallic hydrides =-1); 3) Oxygen = -2 (in peroxides =-1); (bonded with fluorine =+2)

Front 23

Positive Ion: which elements tend to form them?

Back 23

Metals tend to form positive ions by losing electrons (Na → Na+ e-)

Front 24

Negative Ion: which elements tend to form them?

Back 24

Non-metals form negative ions by gaining electrons (Cl +e- →Cl-)

Front 25

Atomic Mass

Back 25

A weighted average mass of the atoms of an element (assuming the carbon-12 isotope is exactly 12) (ex. Atomic mass of C=35.45 is calculated from two isotopes. Cl-35 and Cl-36)

Front 26

For any substance, write a general formula to convert from Moles to Grams

Back 26

g=(n)(MM) where, n = moles MM = molecular mass g = grams

Front 27

For any substance, write a general formula to convert from Grams to Moles

Back 27

n = g/MM; n = moles; MM = molecular mass; g = grams

Front 28

For any substance, write a general formula to convert from Moles to Number of Particles

Back 28

(n)(6.02x10^23) = P; n = number of moles; P = number of particles

Front 29

For any substance, write a general formula to convert from Number of Particles to Moles

Back 29

n = P/6.02x1023; n = number of moles; P = number of particles

Front 30

Reactants; Products

Back 30

1) The starting materials in a chemical reaction; 2) The substances formed in a chemical reaction

Front 31

Balance Equations: H2 + N2 ↔ NH3; NaCL + Br2 ↔ NaBr + Cl2

Back 31

1) 3H2 + N2 ↔2NH3; 2) 2NaCl + Br2 ↔2NaBr + Cl2

Front 32

Period

Back 32

A horizontal row of elements in the periodic table. All have the same number of shells of e-. Across the period, the elements' properties change.

Front 33

Column or Family

Back 33

A verticle group of elements on the periodic table in the same column. They have similar properties and the same number of valence electrons.

Front 34

Describe the change in atomic radius across the periodic table

Back 34

The atomic radius tends to decrease from left to right across the table and increase down the columns

Front 35

Ionization energy

Back 35

The energy change required for the removal of the outermost electron from the gaseous atom to form a +1 ion

Front 36

Describe the change in Ionization Energy across the periodic table

Back 36

Ionization energy tends to increase from left to right across the table and decrease down the columns

Front 37

Quantum Number

Back 37

A number used to describe the energy levels available to an electron. Each electron in an atom has a unique set of four.

Front 38

Ground State

Back 38

Electron is at its lowest energy level as close to the nucleus as possible

Front 39

Excited State

Back 39

An electron absorbs energy and moves to a higher energy level above the ground state

Front 40

List the names of the four sublevels and their electron capacities

Back 40

sublevel s holds two electrons; p holds 6; d holds 10; f holds 14

Front 41

Which sublevels are present in energy levels 1, 2, 3, and 4-7?

Back 41

1: s; 2: s, p; 3: s, p, d; 4-7: s, p, d, f

Front 42

Describe the shapes of the orbitals: 1) s; 2) p; 3) d; 4) f

Back 42

1) s- sphere; 2) p - dumbbell shape with 2 lobes; 3) d - double dumbbell; most have 4 lobes; 4) f - most have 8 lobes

Front 43

What is the order for filling sublevels (aufbau process) from lowest to highest energy

Back 43

1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d

Front 44

Electron configuration

Back 44

The distribution of electrons into shells and sublevels for an atom of an element. Each element has a unique electron configuration.

Front 45

Valence

Back 45

The number of electrons in the atom's highest numbered shell.

Front 46

List the four steps of the scientific method

Back 46

1. observation & collection of quantitative or qualitative data

2. formulation of a hypothesis to explain the observation

3. prediction based on the hypothesis

4. testing the prediction

Front 47

Nature seeks a position of _________energy and favors a change in E that is __________

Back 47

Lowest

Negative

Front 48

Electromagnetic Force

Back 48

When charged particles are brought together, the are either attracted, or repelled by each other

Front 49

Coulomb's Law

Back 49

Energy = Force * Distance

E ~ q1q2 / r

Front 50

For attractive forces, E is _________

Back 50

Negative

Front 51

For repulsive forces, E is ___________

Back 51

Positive

Front 52

When a proton and an electron move apart, there is a(n) _______ in energy

Back 52

Increase

Front 53

All waves travel at ___________

Back 53

The speed of light

(c) = 2.998 * 10^8 ms^-1

Front 54

Long wavelength =

______________ frequency

&

_________________ energy

Back 54

Low

Front 55

short wavelength =

_________ frequency

&

___________ energy

Back 55

High