Chemistry Final Study

What is the systematic process used for investigating the material world?

The Scientific Method

In the scientific method, the step that involves using senses or machines to notice a phenomenon is called _____.

Observation

What characteristic must a scientific 'Question' have based on an observation?

It must be specific and testable.

A statement that predicts the answer to a scientific question is known as a(n) _____.

Hypothesis

According to the validation rule, a hypothesis can never be proven true; it can only be _____ or _____.

Supported or rejected

In an experiment, what are the factors that remain constant called?

Controls

Factors in an experiment that are changed or manipulated are called _____.

Variables

How does the independent variable relate to the dependent variable?

Changing the independent variable results in a change in the dependent variable.

Scientific Model

An explanation of how phenomena occur and how data or events are related.

What is a 'Theory' in a scientific context?

A broad generalization that explains a set of facts or phenomena.

Data that is numerical and measurable is classified as _____ data.

Quantitative

What is the definition of 'Matter'?

Anything that has mass and takes up space (volume).

The smallest unit of matter that retains the properties of an element is the _____.

Atom

Two or more atoms combined through a bond form a(n) _____.

Molecule

Pure Substance

Matter containing only one type of atom with unique chemical and physical properties.

A gas composed of single atoms that do not bond to others, such as Helium, is called _____.

Monoatomic

The Law of Conservation of Mass states that matter cannot be _____ or _____.

Created or destroyed

In a chemical reaction, which two properties must always be conserved?

Mass and charge

What is 'Energy' defined as in a physical system?

The ability to do work.

Energy associated with the motion of an object is called _____ energy.

Kinetic

Energy that is stored and waiting to be used is called _____ energy.

Potential

How many Joules are equivalent to 1 calorie (cal)?

4.184 J

One Food calorie (Cal or kcal) is equal to _____ scientific calories (cal).

1000

What does 'Temperature' specifically measure in a sample of matter?

The average kinetic energy of the particles.

Heat

The transfer of thermal energy from one substance to another.

In a chemical reaction, what is the symbol ΔH used to represent?

Heat of reaction (change in heat).

Why do chemical systems undergo reactions to reach a lower potential energy?

To achieve a more stable state.

The Greek philosopher Democritus proposed the idea of 'Atomos', which means _____.

Indivisible (or that which cannot be divided).

Which philosopher rejected the idea of atoms and believed matter was made of earth, water, air, and fire?

Aristotle

John Dalton's atomic theory stated that all atoms of a given element are _____.

Identical

Which scientist discovered the electron using a cathode ray tube?

J. J. Thomson

What was the main conclusion of Ernest Rutherford's Gold Foil Experiment regarding atomic structure?

The atom is mostly empty space with a small, dense, positively charged nucleus.

Which subatomic particle was discovered by James Chadwick in 1932?

The Neutron

What is the charge and mass (in amu) of a proton?

Charge: +1; Mass: 1 amu.

What is the charge and location of an electron within an atom?

Charge: -1; Location: Outside the nucleus.

The number of _____ in the nucleus determines the 'Atomic Number' and identity of an element.

Protons

Isotope

Atoms of the same element that have different numbers of neutrons (and thus different masses).

How is the modern periodic table arranged?

By increasing atomic number.

Elements in the same group of the periodic table have similar chemical properties because they have the same number of _____.

Valence electrons

What is the name of the Group 17 elements?

Halogens

What is the name of the Group 18 elements, which are known for being inert and monatomic?

Noble Gases

Nuclear Charge

The total charge of the nucleus (determined by the number of protons), which attracts the electron cloud.

What is the 'Shielding Effect' in an atom?

Inner core electrons interfering with the attraction between the nucleus and valence electrons.

The tendency of atoms to prefer a full valence shell (usually 8 electrons) is known as the _____.

Octet Rule

What is the trend for 'Atomic Radius' across a period from left to right?

It decreases due to increased nuclear charge.

Why does 'Atomic Radius' increase as you move down a group?

Because of the shielding effect and the addition of more Principal Energy Levels (PELs).

Ionization Energy (IE)

The energy required to remove an electron from an atom.

Ionization energy _____ across a period and _____ down a group.

Increases; decreases

Electronegativity (EN)

A unitless measure of an atom's desire to keep its electrons and gain more.

When a neutral atom loses electrons to become a cation (+), its radius gets _____.

Smaller

When a neutral atom gains electrons to become an anion (-), its radius gets _____.

Larger

Between which types of elements does 'Covalent Bonding' typically occur?

Between nonmetals.

To form a covalent bond, the two elements must have an electronegativity difference of _____ or less.

2.0

List the seven 'Diatomic Elements' that naturally form pure compounds of two atoms.

H₂, N₂, O₂, F₂, Cl₂, Br₂, I₂

In a Lewis Structure, what does a single line represent?

One shared pair of electrons (2 total electrons).

A double bond involves the sharing of _____ electrons between two atoms.

4

A triple bond involves the sharing of _____ electrons between two atoms.

6

Which element is most likely to be the 'central atom' in a molecule if multiple elements are present?

Carbon

What is the Greek prefix used for 'four' in covalent nomenclature?

Tetra-

What is the Greek prefix used for 'seven' in covalent nomenclature?

Hepta-

In naming binary molecular compounds, what suffix is added to the second element?

-ide

When naming the first element in a covalent compound, when should the prefix 'mono-' be used?

Never (the 'mono-' prefix is dropped for the first element).

Name the covalent compound with the formula P₄O₁₀.

Tetraphosphorus decoxide

What is the formula for 'Dichlorine heptoxide'?

Cl₂O₇

Acids are substances that often start with the element _____.

Hydrogen

Polyatomic Ion

A charged group of covalently bonded atoms that acts as a single unit.

What is the name and formula of the only common positively charged polyatomic ion (cation)?

Ammonium (NH₄⁺)

What is the name of the polyatomic ion OH⁻?

Hydroxide

What is the difference between the polyatomic ions 'Nitrate' and 'Nitrite'?

Nitrite (NO₂⁻) has one less oxygen than Nitrate (NO₃⁻).

Between which types of elements does 'Ionic Bonding' occur?

Metals and nonmetals.

In ionic bonding, the metal _____ electrons to become a _____.

Loses; cation

In ionic bonding, the nonmetal _____ electrons to become a _____.

Gains; anion

Why do metals have a tendency to lose electrons?

They have low ionization energy and low electronegativity.

When drawing ionic Lewis structures, what must be placed around the symbols to show they are ions?

Brackets (and the charge).

What is the 'Golden Rule' of balancing charges in ionic compounds?

The total positive charge must equal the total negative charge (net charge is zero).

The method of using an element's charge as the subscript for the other element in an ionic formula is called the _____.

Criss-cross method

Ionic formulas must always be reduced to the _____.

Lowest whole-number ratio

What is required in the name of an ionic compound containing a transition metal (d-block)?

A Roman numeral indicating the metal's charge.

Name the ionic compound MgCl₂.

Magnesium chloride

What is the name of Fe₂O₃?

Iron(III) oxide

When naming an ionic compound with a polyatomic ion, when should you change the polyatomic ion's name to end in '-ide'?

Never (polyatomic ion names are not changed).

VSEPR Theory

Valence Shell Electron Pair Repulsion theory; used to predict molecular geometry based on electron repulsion.

In VSEPR theory, a single bond, a double bond, and a lone pair each count as exactly _____ electron domain.

One

What is the 'Electron Geometry' of a molecule with 4 electron domains?

Tetrahedral

If a molecule has 3 domains and 0 lone pairs, its molecular geometry is _____.

Trigonal planar

What is the 'Molecular Geometry' of water (H₂O), which has 4 domains including 2 lone pairs?

Bent

Resonance

When multiple valid Lewis structures can be drawn for a single molecule (usually involving a moving double bond).

How do you calculate 'Formal Charge' (FC) for an atom?

FC = Valence Electrons - (Dots + Dashes)

Regarding formal charge, which values are most preferred for a stable structure?

Formal charges of 0.

What is the 'Bond Order' of a double bond?

2

Intermolecular Forces (IMFs)

Forces of attraction between molecules.

Which type of IMF is the weakest and present in all molecules?

London Dispersion Forces

What are the four main types of IMFs listed in the review?

Electrostatic, Dipole-Dipole, Hydrogen Bonding, and London Dispersion.

What is 'Stoichiometry' used for in chemistry?

To understand relationships between amounts of chemicals in chemical equations.

Conversions between different chemicals in a reaction always require a(n) _____.

Mole ratio (from balanced equation coefficients)

What is 'Avogadro’s number'?

6.022 × 10²³ particles per mole.

What is the first step when converting the 'Mass of A' to 'Moles of B'?

Convert Mass of A to Moles of A using molar mass.