BISC104 - Chapter 2 Flash Cards
What is a double covalent bond?
- 2 atoms share 4 electrons - double bonds are stronger than single bonds - ex. O=O
What is a molecule?
- a group of atoms bonded together - every combination of atoms is a molecule ex. O2 and N2
What is a compound?
- a molecule containing atoms of more than one element - a compound is a molecule made of atoms from different elements - all compounds are molecules, but not all molecules are compounds. ex. H2O snd C6H12O6
What is atomic number?
- all atoms of an element have the same number of protons - also gives number of electrons if an atom is electrically neutral
What is the purpose of the plasma membrane?
- also called the cell membrane, is the membrane found in all cells that separates the interior of the cell from the outside environment. - in bacterial and plant cells, a cell wall is attached to the plasma membrane on its outside surface
What are isotopes?
- atoms of the same element that differ in the number of neutrons - they have the same number of protons but a different number of neutrons (different mass numbers)
What is mass number?
- equal to the sum of protons and neutrons — electrons have about zero mass - atomic weight changes with gravity
What is the plasma membrane made of?
- phospholipids form the bulk of the plasma membrane (bilayer) and also consist of proteins - the polar phosphate head end of the molecule is water-soluble (hydrophilic) while the nonpolar fatty acid tails are not water-soluble (hydrophobic)
What is matter?
- refers to anything that takes up space and has mass - it can exist as a solid, liquid, or gas - composed of elements
What is the octet rule?
- valence shell — outermost shell - if an atom has more than 2 shells, the outer most shell is most stable with 8 electrons - atoms can give up, accept, or share to have 8
What is a single covalent bond?
- when 2 atoms share electrons - 1 line represents 1 pair of shared electrons - ex. H-H = H2
The electron arrangement for argon, which has 18 electrons, is?
2 in the inner electron shell, 8 in the second electron shell, and 8 in the outer electron shell
Label the reactants and the products of the following reaction. Some choices will be used more than once. 6 CO₂ + 6 H₂O -------> C₆H₁₂O₆ + 6 O₂
6 CO₂ + 6 H₂O -------> C₆H₁₂O₆ + 6 O₂ reactant, reactant product, product
What is the average pH of blood?
7.35-7.45 (slightly alkaline/basic)
What is an ionic bond?
An ionic bond is the electrostatic force that holds ions together when they form bonds.
How is an octet formed?
An octet is formed via ionic bonding when one or more valence electrons are transferred from one atom to another. An octet is formed via covalent bonding when valence electrons are shared between atoms.
pH is how much ____+ there is in a solution compared to how many ______- there are
H+; OH-
Cola has a pH of 3.5. This means that it has an excess of _______ ions and would be called a(n) ________?
H+; acid
When water molecules are combined, what is the orientation of oxygen and hydrogen atoms of different molecules?
Oxygen atoms of one molecule attract hydrogen atoms of other molecules, so that each oxygen atom is opposite the two hydrogen atoms from nearby molecules.
What do lemons, tomatoes, and coffee all have in common chemically?
They all produce H+ ions in solution, making them acids.
A polar covalent bond can be best described as?
a bond where electrons are unequally shared, resulting in more electrons orbiting certain atoms than others.
What is an organic compound?
a compound that contains carbon
What is an inorganic compound?
a compound that does not contain carbon
What is a polar molecule?
a molecule in which the charges are unevenly distributed
What is a nonpolar molecule?
a molecule whose electrons are shared evenly by the atoms in the molecule
What is an element?
a substance that cannot be broke down into another substance by ordinary chemical means
A pH below 7 is?
acidic (more H+ than OH-)
Water also exhibits ____________, which is the ability to cling to other polar surfaces, because of its polarity.
adhesion
A pH above 7 is?
basic (more OH- than H+)
Water has a high heat ________________, which allows it to absorb heat without greatly changing its temperature, and a high heat of _______________, which prevents it from easily becoming a gas and evaporating into the environment.
capacity; vaporization
What are buffers?
chemicals or combinations of chemicals that keep pH within normal limits it resists pH change by taking up excess H+ or OH-
Because of the high number of hydrogen bonds, water exhibits _____________, meaning the molecules cling together. Under ordinary conditions of temperature and pressure, water exists as a __________.
cohesion; liquid
Glucose, C6H12O6, is best described as a(n)?
compound
In water, oxygen shares a bond with two hydrogen atoms. Oxygen is more ___________________ than hydrogen, making the bond _____________ with the oxygen being the negative end and the two hydrogens being the positive end.
electronegative; polar
A covalent bond occurs when
electrons are shared between two atoms to complete their octets
True or false; Compared to the polar covalent bonds that hold the oxygen and hydrogen atoms together within a molecule of water, the hydrogen bonds that hold multiple water molecules together are much stronger.
false
True or false; Electrons possess a negative charge. So, within a molecule of water, if more electrons are orbiting the oxygen atom than the two hydrogen atoms, the oxygen atom will have a slightly more positive charge than the hydrogen atoms.
false
Because it is a polar compound, individual water molecules are attracted to one another by ________________ bonds, which form because of the attraction between the positive hydrogen atoms and the negative oxygen atoms.
hydrogen
pH is the relative scale of ____________ ions
hydrogen
The weak attractions between water molecules are known as?
hydrogen bonds
The weak attractive forces that hold water molecules together are called
hydrogen bonds
An atom that has an electrical charge is called a(n)?
ion
What are the two types of bonds?
ionic — attraction between opposite charges; forms when 2 atoms are held together by the attraction between opposite charges covalent - sharing electrons to complete outer shell
The (more or less) H+ you have results in an acid?
more
What is the location and charge of an electron?
negative charge; found outside of the nucleus, moving in orbitals
a pH of 7 is?
neutral (H+ is equal to OH-)
What is the location and charge of a neutron?
no electrical charge; found in nucleus
Is water polar or non-polar?
polar
What is the location and charge of a proton?
positive charge; found in nucleus
When atoms combine to form compounds, they can ________________ electrons.
share
What is a hydrogen bond?
slightly positive hydrogen of one water molecule attracted to the slightly negative oxygen in another water molecule
Water can also be used as a _____________ for many polar and ionic substances. Molecules that are attracted to water are said to be _______________.
solvent; hydrophilic
What does the atomic theory say?
that elements consist of atoms
What is an atomic symbol?
the name of the atom or element ex. H for hydrogen or Na for sodium
True or false - the number and arrangement of electrons in an atom governs its chemical activity
true
Why is water a polar molecule?
water has positive hydrogen atoms and negatively charged oxygen atoms
