Chem Final Definitions + MCQ

Endothermic Reaction

A chemical reaction in which a greater amount of energy is required to break the existing bonds in the reactants that is released when the new bonds form in the product molecules

Exothermic Reaction

A chemical reaction or process in which more energy is released than is required to break bonds in the initial reactions

Sigma Bond

A single covalent bond - formed by direct overlap of orbitals

Pi Bond

A bond formed when parallel orbitals overlap to share electrons

Resonance

Conditions that occurs when more than one valid Lewis structure exists for the same molecule

Coordinate Covalent Bond

When one atom donates a Paris of electrons to be shared with an atom or ion that needs two electrons to become stable

Polar Covalent Bond

A type of bond that forms when electrons are not shared equally

Mole

SI base unit that measures the amount of a substance, 6.02 × 10²³

Hydrate

A compound that has a specific number of molecules bound to its atoms

Kinetic Molecular Theory

Bx of gases in terms of particles in motion, makes several assumptions about size, motion, and energy of gas particles

Elastic Collision

Collision in which no kinetic energy is lost, KE can be transferred between colliding particles, but the total KE remains the same

Temperature

Average kinetic energy of particles

Diffusion

The movement of one material through another from an area of higher concentration to an area of lower concentration

Dalton’s Law of Partial Pressure

The total pressure of a mixture of gases is equal to the sum of the pressures of all gases in the mixture

Dispersion Forces

Weak forces resulting from temporary shift in density of electrons in the electron cloud

Dipole Dipole Forces

The attraction between oppositely charged regions of polar molecules

Hydrogen Bond

A strong dipole-dipole attraction between molecules that contain a hydrogen atom bonded to a small, highly electro negative ion

Surface Tension

Energy required to increase the surface area of a liquid by a given amount; results from uneven distribution of attractive forces

Surfacants

A compound that lowers surface tension of water by disrupting hydrogen bonds between water molecules; soap

Crystalline Solid

A solid whose atoms are arranged in orderly, geometric, three-dimensional structure

Allotrope

One or two or more forms of an element with different structures and properties when they are in the same state

Amorphous Solid

A solid in which particles are not arranged in a regular, repeating pattern that often is formed when molten material cools too quickly to form crystals

Vapor Pressure

The pressure exerted by a vapor over a liquid

Boiling Point

The temperature at which a liquid’s vapor pressure is equal to the external or atmospheric pressure

Freezing Point

The temperature at which a liquid is converted into a crystalline solid

The common name of SiI4 is tetraiodosilane. What is its Molecular compound name?

D - Silicon Tetraiodide

Which compound contains at least one pi Bond?

A - CO2

What is the electronegativity of the element with atomic number 14?

B - 1.8

An ionic bond would form between which pairs of elements?

D - Atomic number 8 and atomic number 12

Which is the Lewis structure for silicon disulfide?

B

The central selenium atom in selenium hexafluoride forms an expanded octet, how many electron pairs surround a central Se atom?

C. 6

Which diotomic gas has the shortest bond between two atoms?

D. N₂

Approximately how much energy will it take to break all the bonds present in the molecule below?

D. 5011 kJ/mol

Which compound does NOT have a bent molecular shape?

B. CCI₄

What type of reaction is describes by the following equation?

D. Single-replacement

Which reaction between halogens and halide salts will occur?

A. F_2gg)

Which is the electron configuration for iron?

A 1s