Chapter 2 Flashcards
Mass
A measure of the quantity of matter in an object. On Earth, equivalent to the weight of an object.
Matter
Anything that takes up aspace and has mass.
Mass
A measure of the quantity of matter in any given object.
Constituents of an atom
protons, neutrons, electrons.
Electron
Negative charge
Proton
Positive charge.
Neutron
Neutral charge.
Nucleus
The core of an atom where protons and neutrons are.
Element
A substance that is “pure” in that it cannot be reduced to any simpler set of component substances through chemical processes.
Atomic number
The number of protons in the nucleus of an atom.
How are elements ordered on the periodic table?
According to atomic number.
Major elements found in the human body.
Oxygen, carbon, hydrogen.
Major elements found in the Earth’s crust.
Oxygen, silicon, aluminum, calcium, and iron.
Isotopes
A form of an element as defined by the number of neutrons contained in its nucleus. Different isotopes of an element have the same number of protons but differing numbers of neutrons.
An ___ is any form of matter that cannot be reduced to a simpler set of component substances through chemical means. Such forms of matter are defined by the number of ___ in their nuclei.
Element, proton.
Most forms of matter can come in several varieties, called isotopes, in accordance with the numbers of ___ in their nuclei.
Neutrons
Chemical bonding
The process of chemical combination and rearrangement.
Ionic bonding
A linkage in which two or more ions are bonded to each other by virtue of their opposite charge, so outer shells of each are completed.
Covalent bonding
A type of bonding where one atom can share one or more electrons with another atom. They can be polar and nonpolar.
When is an atom most stable?
When their outer shells are filled.
How many electrons are required to fulfill each energy level?
Two electrons for the first level and eight for subsequent levels.
Law of conservation of mass
States that matter is neither created nor destroyed in a chemical reaction.
Molecule
an entity consisting of a defined number of atoms covalently bonded together.
Electronegativity
The measure of the strength of attraction of an atom has for electrons that are being shared in a covalent bond. An atom with higher electronegativity will tend to pull electrons toward itself, away from atoms with lower electronegativity.
Polarity
A difference in electrical charge at one end as opposed to the other.
Polar covalent bond
A type of covalent bond in which electrons are shared unequally between atoms, so that one end of the molecule has a slight negative charge and the other end a slight positive charge. They are shaped unevenly due to the unequal distribution.
Nonpolar covalent bond
A type of covalent bond in which electrons are shared equally between atoms.
Ion
A charged atom or, an atome whose number of electrons differs from its number of protons.
Ionic compound
A collection of the atoms of two or more elements that have become linked through ionic bonding.
Hydrogen bond
A chemical bond that links an already covalently bonded hydrogen atom with a second, relatively electronegative atom. It is a weak bond.
An ionic bond occurs when one atom ____ one or more ____ to another atom and the resulting ions become attached because of their differing ____.
losses, electrons, charges.
A hydrogen bond links an already covalently bonded hydrogen atom with a more ____ atom. In biology, such bonds almost always occur between hydrogen and either ____ or ____.
Electronegative, oxygen, nitrogen.
Molecular shape is important in biology because it determines the ability that molecules have to ____ with one another.
Bind.
Atom stability
All atoms are most stable when their outer electron shell is either filled with electrons or is empty, but inner shells must be filled before an outher shell receives electrons.
Types of covalent bonds
Polar and nonpolar.
Molecule behaviour
Depends largely on their electrical charges.
Orbitals
Spaces in energy levels. Each orbital can hold two electrons in it. First energy level has one orbital, and subsequent have 4 orbitals.
Van der Waal
Even when electrons are shared equally, when atoms are spinned, sometimes their bonds become weak and polarized, making the element share electrons unequally.
Solution
A mixture of two or more kinds of molecules, atoms, or ions that is homogenous.
Solute
The substance being dissolved by a solvent to form a solution.
Solvent
The substance in which a solute is dissolved to form a solution. In an aqueous solution, the solvent is water.
Homogeneous
meaning uniform throughout
What generally makes water work as a solvent?
Its ability to form, with other molecules, hydrogen bonds.
Water properties
Cohesion, adhesion, high specific heat, surface tension, density when frozen.
Cohesion
made up of polar covalent bonds. One water molecule can stick to another water molecule.
Specific heat
The amount of energy required to raise the temperature of a substance by 1* Celsius.
Adhesion
Because hydrogen bonds are weak, water has slightly positive and slightly negative regions that can form hydrogen bonds with other polar molecules.
Surface tension
water molecules below the surface are attracted to one another, while those on the surface ARE NOT attracted to the air; therefore, water molecules create an almost solid surface.
High-specific heat
Hydrogen bonds are constantly breaking and forming new hydrogen bonds. Because of the many hydrogen bonds constantly breaking and reforming, water strongly resists temperature change, so it takes a lot of energy to change its temperature. Molecules move apart when they heat up.
Density
When water cools down, molecules get closer together, making water denser. Densest at about 4* C. Below 4* C, water starts to expand and become less dense.
Hydroxide ion
Water molecule missing one of the hydrogens but is keeping the electrons t would share with that hydrogen. Combine with hydrogen to form water.
Acid
Chemical that adds/increases the amount of hydrogen ions (H+) in a solution. When combined with a base, it tends to be neutralized and form water.
Base
Chemical that removes hydrogen ions because it adds hydroxide ions to a solution (OH-). Combines with an acid (H+) to form water.
pH scale
Measures how acidic or how basic a solution is. Ranges from a scale of 1-14. Is an inverse measure of how many H+ ions are in a solution. 1 is most acidic, 14 most basic.
Acidic products
Battery acid, hydrochloric acid, lemon juice, gastric juice, cola, beer, vinegar, wine, tomatoes, black coffee, urine
Basic products
Lye, household ammonia, oven cleanser, household ammonia, Great Salt Lake, baking soda, sea water
Hydrophilic
The property of being able to form chemical bonds with water molecules.
Hydrophobic
The property of being unable to form chemical bonds with water molecules.
Alkaline
A solution that is basic is also referred to as alkaline.
Acid-base buffering systems
Physiological systems that function to keep pH within normal limits.
Acid rain
Rain whose pH level has been skewed toward the acidic side of the pH scale, with air pollution being the cause of this shift.
Hydrogen electrons
1
Carbon electrons
6
Nitrogen electrons
7
Oxygen electrons
8
Phosphorous electrons
15
Sulfur electrons
16
Living things tend to have internal pH environments that hover around _____.
neutral (7)
An acid is any substance that ____ hydrogen ____ when put into an aqueous solution, while a base is any substance that ____ them.
yields, ions, accepts.
