Science GACE

Hygroscopicity

the ability of a substance to absorb moisture from the air, often leading to changes in physical or chemical properties

pH Scale: Neutral

a substance measuring 7 on the pH scale, contains equal parts acid and base

Chemical Property

refers to the characteristics of a substance that become evident during a chemical reaction or chemical change

Solubility

the ability of a substance to be dissolved in a solvent

Heterogeneous Mixture

a mixture that is not uniformly mixed

Texture

the feel, appearance, or consistency of the surface of a material

Inert Element

an element that rarely react with other elements

Intensive Properties

properties that do not depend on the amount of substance present

pH Scale

a scale indicating acidity or how basic a substance is: 7 is neutral, less than 7 is acidic, more than 7 is basic

Chemical Reactivity

a measure of the tendency of an atom, molecule, or compound to undergo a chemical change

Electronegativity

the tendency of an atom to attract electrons toward itself

Solute

the material in a solution that is dissolved in the solvent

pH Scale: Acid

a substance between 0 and 7 on the pH scale; contains more hydrogen ions (H+) than hydroxide ions (OH-)

Concentration

concentration is the amount of solute dissolved in a solvent, usually expressed as moles of solute per liter of solution

Flammability

the tendency of a material to ignite

Magnetism

the response of a mineral when exposed to magnetic materials; a physical property

Group (on Periodic Table)

each column on the periodic table is called a group or family

Ductility

the ability of a material to be drawn into thin wires

Lewis Acid

substances that act as electron pair acceptor

Solvent

a substance which dissolves other substances

Hardness

the mineral's resistance to scratching; measured on the Mohs scale, where talc, the softest mineral, has a score of 1 and diamond, the hardest, has a score of 10

Valence Electron

an electron in the outermost shell of an atom in the ground state; the only type of electron involved in bonding

Arrhenius Acid

solutions that ionize in water to produce a positive hydrogen ion, or a proton

Physical Change

a change in the appearance of a material with no change to its chemical composition

Radioactivity

when an atom changes the number of protons in the nucleus and releases radiation

Volatility

how easily a substance turns into a vapor (gas) at a given temperature

Chemical Stability

the tendency of a substance to resist undergoing chemical changes or reactions under specific conditions

Conductivity

the ability of a material to allow the flow of heat or electricity

Metallic Character

Elements that show stronger metallic properties such as conductivity, malleability, ductility, and luster; greater in elements that easily lose their valence electrons.

Brønsted-Lowry Acid

substances that act as a hydrogen ion donor

Period (on Periodic Table)

each row on the periodic table is called a period

Spontaneous Reaction

A chemical reaction that occurs when elements are combined even when no extra energy is present.

Density

the amount of mass present in a given volume, reflection of how tightly packed the atoms are

Metallic Qualities

Qualities typically associated with metals such as magnetism, conductivity, malleability, and ductility

Brønsted-Lowry Base

substances that act as a hydrogen ion acceptor

Crystalline Structure

the degree to which the mineral is arranged in a crystal lattice structure; the more crystalline the mineral is, the harder that lattice is to see with the naked eye

Corrosiveness

the tendency of a substance to cause deterioration or damage to materials through chemical reaction, often leading to the breakdown of metals or other materials

Compound

groups of two or more different elements held together by ionic or molecular bonds

Family (on Periodic Table)

each column on the periodic table is called a group or family

Homogeneous Mixture

a mixture with the same ratio of parts throughout the mixture

State of Matter

whether an element is a solid, liquid, or gas at given conditions

Periodic Table

a chart of the elements, organized by physical and chemical properties of the different types of atoms

Polarity

the distribution of electric charge within a molecule, resulting in regions with partial positive and negative charges

Physical Properties

properties that can be observed without changing the chemical makeup of the substance

Radioactive Decay

a process that changes the nucleus of an atom by emitting high-energy alpha, beta, and/or gamma particles

Extensive Properties

properties that depend on the amount of substance present

Arrhenius Base

solutions that ionize in water to produce a negative hydroxide ion

Mixture

a substance in which the atoms, molecules, or particles of two or more different materials are mixed but not chemically combined

Solution

a mixture in which one substance dissolves in another

pH Scale: Base

a substance measuring between 7 and 14 on the pH scale; contains more hydroxide ions (OH-) than hydrogen ions (H+)

Toxicity

the ability of a substance to cause harm or poison when ingested, inhaled, or absorbed through the skin

Luster

the ability of the mineral's surface to reflect light; can be metallic, submetallic, or nonmetallic

Ionization Energy

the amount of energy needed to remove an outer electron to make a positive ion

Phase Change Temperatures

the temperatures at which an element changes from one state of matter to another (solid, liquid, gas)

Atomic Radius

the distance from the nucleus to the outer electron shell

Electron Affinity

the ability to accept an electron and become a more negative ion

Malleability

the ability of a material to be hammered or pressed into shape without breaking

Pure Substance

a substance that consists of only one type of atom or molecule

Lewis Base

substances that act as electron pair donor

A solution of 7 on the pH scale is:

neutral.

Which of the following elements has the highest reactivity when considering periodic trends?

sodium

Sodium and water react to form sodium hydroxide, NaOH. Which of the following is produced in a similar reaction with water?

KOH

Which of the following will increase the rate of dissolution of a solid compound in water?

using a powder instead of large pieces of solid

Which of the following could be the pH of 0.2 M of HCl at 25°C?

3

Which of the following chemicals is a Brønsted-Lowry base but not an Arrhenius base?

NH₃ (aq)

Which of the following is a chemical property?

flammability

Which of the following atoms has the smallest diameter?

F

A water molecule (H₂O) can break into a positively charged H+ ion and a negatively charged OH- ion. Bases have an excess of which kind of particle?

OH−

Which of the following is the best example of a heterogeneous mixture?

Layered gravel at the bottom of an aquarium.

Kinetic Energy

the energy of motion

Groundwater Recharge

the process through which water from precipitation or surface sources infiltrates into the subsurface, replenishing underground aquifers

Algal Bloom

a rapid increase in the population of algae in a marine community

happens naturally, but it can also be caused by excess fertilizer from farms entering waterways

Biosphere

region of the Earth in which all life exists. It extends from deep in the oceans into the atmosphere.

Altitude

height above sea level, typically measured in meters or feet

Photosynthesis

process by which plants use light, water, and carbon dioxide to make their own food (sugar) and oxygen

Adhesion

the ability of water molecules to stick to other substances

Hydraulic Conductivity

ability of soil or rock to transmit water, influenced by factors like porosity, permeability, and particle size

Canal

a man-made waterway made to allow boats to pass through or to transport water for irrigation purposes

Denitrification

the process by which nitrogenous compounds in the soil are converted back into nitrogen gas

Exosphere

a layer in the atmosphere which provides a boundary between the thermosphere and outer space

Percolate

to travel from the surface to groundwater through the spaces between soil and rock particles

Gulf

an inlet of the sea or ocean bordered on several sides by land

Stream

a natural, flowing waterway; smaller than a river; composed of freshwater

Atmosphere

the gases surrounding the surface of the earth

Ocean

the largest type of water body; composed of saltwater; divided into the Pacific, Indian, Atlantic, Southern, and Arctic Oceans

Lake

a landlocked basin filled with water; usually freshwater. Can be used for recreation, fishing, hydroelectric power, and/or as a water source

Surface Water

water held on the surface of the earth

Lithosphere

the rigid, outermost layer of the earth composed of the crust and the uppermost mantle

Water Cycle / Hydrologic Cycle

the process by which water circulates between the earth and the atmosphere

Meteoroids

small bodies of debris from space which move into Earth's atmosphere and can then turn into meteors

Groundwater

water below the earth's surface held in the spaces between rock and soil particles

Mesosphere

the coldest layer in the atmosphere; protects the earth from meteoroids

Stratosphere

the layer above the troposphere; contains jet streams and the ozone layer

Hydrosphere

all of the water on the planet in all of its states (solid, liquid, gas)

Ultraviolet Radiation

radiant energy which can heat up the planet and damage the cells of living organisms

River

A large stream that flows over land, usually carrying a large amount of freshwater

Positive Feedback

a type of input into a system in which the result causes the system to continue on the path in which it was headed before the input

Reservoir

large body of still surface water similar to a lake; used for recreation, as a water supply, or for hydroelectric power

Negative Feedback

a type of input into a system in which the result causes the system to return closer to previous conditions

Water Table

the level below which the soil and rock remain saturated with water