Chapter 2 Flashcards
Matter
Anything that takes up space and has mass. Matter is made up from atoms
Element
A pure substance made up of only one kind of atom
Molecule
2 or more atoms bonded together
Compound
A substance consisting of two or more different elements combined in a fixed ratio. Table salt for example is Na(sodium) and Cl(chloride)
Essential elements
A chemical element required for an organism to grow, survive and reproduce. 25of the 92 natural elements are essential for humans. Plants need 17
What makes up 96% of living matter? And the other 4%?
Oxegyn, hydrogen, carbon, nitrogen
Calcium phosphorus, potassium, sulfur and a few others
Trace elements
Elements required by an organism but only in minute quantities.
Atom
The smallest functional units of matter.. Make up all chemical substances and ultimately all organisms
Subatomic particles
The smaller parts that make up an atom. Neutrons protons and electrons are examples
Protons
Electrically and positively charged. Packed tightly with electrons into the atomic nucleus at the center of an atom
Electron
Electrically and negatively charged. Also in the atomic nucleus with the protons. Electrons move rapidly forming a cloud of electric charge around the nucleus. It is the attracting of opposite charged that keeps the electrons in the vicinity of the nucleus.
Neutron
Electrically neutral
Dalton
The unit of measurement for atomic mass equal to roughly the mass of s proton. named after John dalton the British scientist who helped developed atomic theory around 1800.
Atomic mass
It is approximately the equivalent of the usual number of protons and neutrons. Allowing for differences with isotopes
Atomic number
The number of protons an atom has in their nuclei. It is written as a subscript to the left of an elements abbreviation. Unless other wise indicated, an atom is neutral in electrical charge so if it has 2 protons then it has 2 electrons also. Atomic number tells us he number of protons and electrons an electrically neutral atom has
Simplest atom
Hydrogen. Helium is #2
Atomic nucleus
Small dense region consisting of protons and neutrons which gives the atomic nucleus a slight positive charge
Electron speed
An electron could orbit the earth in less than 20 seconds
Orbital
Area where an electron can be found. First one is s shape, second layer is one s and 3 p orbitals
Energy
The capacity to do work to cause change
Lowest energy electrons go
In the first she’ll
Valence electrons
Electrons in the outermost she’ll
Net electric charge of zero
With the exception of ions, the number of protons and electrons is equal which results in a net electric charge of zero
Rows in periodic table
Known as periods, go up and down. They indicate the number of electron shells with the least being at the top
Columns in periodic table
Aka groups read left to right and indicate the number of electrons in the outer shell
Weight vs mass
Weight is the gravitational pull on mass. It is different on earth or the moon but mass is always the same
Mole
Amount of a substance that has as many atoms/molecules/ions/ electrons or photons as atoms in 12 grams of carbon.
Isotope
An element that has a different amount of neutrons than it usually would
Radioisotope
Unstable; how long now they last is measured in half lives ( the time it takes for 50% of the isotope to decay) they emit radiation which in turn makes them more stable
2 ways radioisotopes are used for good
H
Water makes up
60% of humans, 95% of plants
Carbon is* nitrogen is*
A major building block for all living matter,* a vital element in all proteins
Mineral elements essential for life
Calcium, chlorine, magnesium, potassium, phosphorus, sodium, sulfur
Key regulators of water and electric current
Potassium and sodium
Makes skeletons and shells
Calcium and phosphorus
Molecular formula
When the chemical symbols for all atoms present are written out. H20 is and example. The 2 next to h tells you there is 2 hydrogen
Emergent properties
The properties of a compound differ greatly from the properties of the elements that make it up
Covalent bonds
Bond where atoms share electrons. They are strong because the shared electrons act as if they belong to each atom
Structural formula
H-O-H covalent Bonds are shown with a line
Octet rule
Many atoms are most stable when they have 8 electrons in their outer shell
Double bond
When atoms share two pairs(4 electrons) written with two lines
Electronegativity
The measure of an atoms ability to attract electrons in a bond with another atom
Polar covalent bonds
A bond in which electrons are shared, but not equally. The atom with a higher electronegativity hordes the shared electrons
Kinetic energy
The energy of moving matter
Water and how it’s polar/ electronegative
Oxegyn is more electronegative than hydrogen so the shared electrons pull closer to the nucleus of oxegyn than to the hydrogen. This unequal distribution of electrons gives the molecule a region of partial negative charge
Nonpolar covalent bonds
Two atoms of similar electronegativity covalently bond and share the electrons equally
Hydrogen bond
Hydrogen atom from one polar molecule is attracted to an electronegative atom such as oxegyn or nitrogen from another polar molecule
Enzymes
Type of protein found in all cells that facilitates or catalyzes many important chemical reactions
Can see waals dispersion forces
Also a weak molecular attraction. Because the atoms are always moving around they end up sometimes being in a position that gives the atom a electric charge that doesn’t last. This electric charge causes attraction but dies quickly
Ion
When an atom gains or loses an electron it acquires a net electric charge
Cation
Ions with a net positive charge ( this would be an ion with maybe 11 protons and 10 electrons
Anion
Ions with a net negative charge, more electrons than protons
Ionic bond
Occurs when a cation bonds to an anion. An example is na+ and Cl- which form table salt.
Free radical
A molecule containing an atom with a single unpaired electron in its outer shell. In an attempt to get an electron they may steal one from another molecule which in turn makes that molecule a free radical, it’s a chain reaction.
Antioxidant
molecules that can donate an electron without becoming highly reactive. Examples of this of vitamin c and e found in fruits, veggies and plant compounds called flavonoids
Chemical reaction
When one or more substances are changed into other substances by the making or breaking of chemical bonds
All chemical reactions
Need Energy to make the molecules encounter eachother, a catalyst of some sort. And they all proceed in a particular directional until they reach chemical equilibrium. Also most happen in watery substances
Chemical equilibrium
When the rate of formation of product equals the rate of formation of reactants aka. The concentration of products and reactants stops changing.
Water: brain, blood, lungs
Brain: 70%, blood: 80%, lungs:90%
Solute
Substance dissolved in water
Solvent
The liquid dilutes are dissolved into. Water is the most abundant solvent in nature
Solution
When a solute is dissolved into a solvent this is the product
Why do some things dissolve in water
The covalent bonds linking hydrogen and oxegyn are POLAR. This leaves oxegyn with a slight negative charge and the hydrogen a with a slight positive charge. To dissolve in water the substance must be electrically attracted to h2o. Generally molecules with ionic or polar bonds will dissolve
Hydrophilic
Water loving, molecules that are attracted to water
Hydrophobic
Water fearing. Molecules that have mostly carbon or hydrogen will be hydrophobic because their bonds are non polar and therefor not attracted to h2o, oils are hydrophobic.
Amphipathic; what they do in water
Molecules with hydrophobic and hydrophilic regions. In water they form spheres called micelles which put all the hydrophobic parts inside the sphere and all the hydrophilic parts on the outside touching the water. Detergents are an example.
They can also form linear structures with two layers, the two outer layers are hydrophilic and the inside is hydrophobic.
Concentration
The amount of dissolved solute per volume. 1 g of Nacl dissolved in 1 liter of water the concentration is 1g/L
Molarity of a solution
F
The three states h2o exists in and the effect the bonds breaking has
Solid(ice) occurs when temperatures fall and the hydrogen bonds break less frequently causing larger and larger clusters of water until it freezes into a crystalline matrix. Liquid(water) most common with hydrogen bonds continuously being broken and formed again. If the temp rises the bonds break quicker and molecules of water escape into a gaseous state, becoming water vapor.
Density of water vs ice
H2o molecules are more orderly and further away in ice which makes ice less dense and allows it to float on water
Heat of vaporization(and for water)
The heat needed to vaporize 1 mole of any substance. This is high for water because all the hydrogen bonds need to be broken
Heat of fusion
The amount of heat that must be withdrawn from a substance to turn it from liquid to solid. This is also high for water.
Specified heating
The amount of energy needed to raise the temperature of 1 gram of a substance by 1degree Celsius
Heat capacity
The amount of heat needed to raise the temp of an entire object or substance. A large container of water has a higher heat capacity than a cup of water
Colligative properties
Properties that depend on the total number of dissolved solutes instead of the type of solutes. Water will freeze at a lower temp than 0degrees if a solute is added and higher than 100 degrees for vaporizing.
Hydrolysis reactions
A chemical reaction that utilizes water to break apart molecules
water is incompressible
It’s volume does not significantly decrease when subjected to high pressure. This is important because many organisms use water to provide support
Cohesion/ adhesion
The phenomenon of water molecules being attracted to eachother
The ability of water to be attracted to and therefor adhere to a surface that is not electrically neutral
Surface tension
A measure of the attraction between molecules at the surface of a liquid
Acid
Substances that release hydrogen ions into solutions
Hydrochloric acid
Strong acid. Almost complety dissolves into H+ and Cl- when mixed with water
Carbonic acid
Weak acid because some of it stays in its H2CO3 state when dissolves in water
Base
Has the opposite effect when dissolved in water, it decreases the concentration of H+
Ph
The measure of the H+ concentration of a solution
Polarity
The unequal sharing of electrons within a molecule
Acidic/ Alkaline
Ph of 6 or less//// A substance with a ph above 7
Normal ph for living cells, and for blood
Living cells= 6.5 to 7.8, in blood 7.35 to 7.45
