Mastering biology 2
Fluorine's atomic number is 9 and its atomic mass is 19. How many neutrons does fluorine have?
10
this atom can form up to single covalent bonds
4
We may never know how many people became ill or died as a result of the Chernobyl accident. What is the main reason why this is so difficult to determine?
Cancer might not occur for many years after exposure to ionizing radiation.
Why is the town of Pripyat uninhabited?
The radiation levels in the town are still unsafe. Submit
a bond joins these two o atoms
double covalent
the tendency of an atom to pull electrons toward itself is referred to as its
electronegativity
each water molecule is joined to other water molecules by bonds
four hydrogen
when water warms or cools, either break or form
h bonds
what name is given to the bond between water molecules
hydrogen
The for a solution that has an equal concentration of H+ and OH- is
neutral
blood and other biological fluids are aqueous solutions with a diversity of dissolved
solutes
an uncharged atom of boron has an atomic number of 5 and an atomic mass of 11. How many p's does boron have?
5
what is the atomic number of an atom that has 6 p's, 6 n's, and 6 e's?
6
a buffer consists of undissociated acid (HA) and the ion made by dissociating the acid (A) how does this system buffer a solution against decreases in pH
A reacts with H to become HA
Life on Earth began in water 3 billion years before spreading onto land.
Evolution
what is sometimes called the univeral solvent. is this accurate
For the most part. Water readily dissolves most substances, but not hydrophobic ones.
An acid is a compound that donates to a solution.
H+
Why is ionizing radiation damaging to cells?
It knocks the electrons from the cell's molecules, forming ions and breaking bonds.
The concrete sarcophagus enclosing the damaged reactor is crumbling, allowing radiation to leak out into the environment. An animation of a new protective cover is shown in the video. Why hasn't the construction of this cover been completed?
It will be extremely expensive to build. Submit
The higher the pH number, the higher the concentration of in a solution.
OH-
Two molecules of hydrogen peroxide react to produce two molecules of water and one molecule of oxygen.
Pathways that transform energy and matter
Earth's giant water supply stores a huge amount of heat from the sun during warm periods and gives off heat that warms the air during cold periods. This enables temperatures on the planet to stay within the limits that permit life.
Pathways that transform energy and matter and Interactions within biological systems
The number of electrons in an atom determines the chemical properties of that atom.
Relationship of structure to function
Although the forest is growing quickly around Chernobyl, and some of the wildlife is thriving, studies show that biodiversity around Chernobyl has been reduced by over 50% since the accident. Why?
The ionizing radiation affects the DNA of the wildlife, just as it affects the DNA of humans. Submit
relative to other substances, water tends to resist changes in temp. why?
Water is highly cohesive. Its molecules tend to resist increases in their motion. When water is heated, some of the energy is used to disturb the hydrogen bonds between neighboring molecules.
buffers work best when
about half of the buffer molecules are dissociated
The term for a solution with a low pH number, such as lemon juice or vinegar, is
acidic
Many of the first responders at the Chernobyl accident died within hours or days of working at the explosion site. What were they most likely to die from, and why?
acute radiation sickness due to exposure to ionizing radiation
Water readily sticks to many other substances, a property called ______.
adhesion
trace elements
also called micronutrients, are any chemical element required by living organisms in miniscule amounts, but cells require them to survive.
which answer helps to explain why all living cells need pH buffers
amino acid side chains have many carboxyl and amino groups
an ionic bond involves
an attraction between ions of opposite charge
matter
anything that occupies space and or has any substance
atoms with the same number of protons but with different electrical charges
are different ions
The term for a solution with a high pH number, such as ammonia or bleach, is
basic
A substance that accepts H+ when they are in excess and donates H+ when their concentration drops is called a(n)
buffer
After oxygen, carbon, hydrogen, and nitrogen, which element occurs in the greatest quantity in your body
calcium
each pill contains the recommended daily allowance of one mineral. of the following minerals, which do you suppose would come in the biggest pill
calcium
the equation shows a - the breaking and forming of chemical bonds that leads to a change in the composition of matter
chemical reaction
the of water molecules to each other helps transport water from the roots to the leaves in plants.
cohesion
Water striders are common insects that can skip across the surface of ponds and streams. This lifestyle is enabled by water's _____. 1) cohesion and resulting surface tension 2) high specific heat 3) adhesion 4) none of the above
cohesion and resulting surface tension
a bond involves the sharing of electron pairs between atoms, also known as a molecular bond
covalent
what type of bond is joining the two hydrogen atoms
covalent: electron pairs are shared
when two pairs of electrons are shared between two atoms, a bond is formed
double
H2SO4, sulfuric acid, contains three different types of atoms: hydrogen (H), sulfur (S), and oxygen (O). Each of these atoms represents a different Since the three types are combined in a fixed ratio, this means that H2SO4 is a(n)
element compound
the number of oxygen atoms on the left side of the equation is the number of o atoms on the right side
equal to
to make a buffer you need to
have a weak acid or weak base half ionized in water
thus water absorbs or releases a great deal of , helping to moderate temperatures. Because is less denses than liquid water, it floats and protects lacks and oceans from freezing solid
heat ice
A weak bond called a ____ bond forms an attraction between a slightly positive region in a molecule and a slightly negative region in the same or a diff molecule
hydrogen
molecule
if two or more atoms are bonded together, they form a
Product
in the equation C6H12O6 is a
reactant
in the equation, CO2 is a
an bond forms when one atom gives up one or more electrons to another atom
ionic
in salt, what is the nature of the bond between sodium and chlorine
ionic
atoms or molecules with a net electric charge due to the loss or gain of one or more electrons are
ions
nitrogen
is one of the four elements that make up 96.3% of living cells.
zinc
is one of the fourteen trace elements and is a component of certain digestive enzymes and other proteins.
calcium
is one of the seven elements that make up a small fraction, approximately 3.7%, of living cells.
which of these refers to atoms with the same atomic number but different atomic masses?
isotopes
how does the way a buffer stabilizes pH during addition of acid differ from the way the same buffer stabilizes pH during addition of base?
its the same reaction running backward or forward
a refers to two or more atoms held together by covalent bonds
molecule
atoms involved in a bond equally share electrons; there is no charge separation to the molecule
nonpolar
atomic number
number of protons in the nucleus of an atom, which determines the chemical properties of an element and its place in the periodic table.
there are four elements that together account for about 96% of your body weight. what four are they
o c n h
which statement best describes why a water molecule is polar
o exerts a stronger pull on the shared electrons than the H do
which one element makes up the majority of your body weight
oxygen
a bond is a type of chemical bond where a pair of electrons is unequally shared between two atoms, as a result, one end of the molecule has slightly negative charge and the other a slightly positive charge
polar
the unequal sharing of electrons within a water molecule makes the water molecule
polar
in O2, the type of bond tha t holds the two oxygen atoms to the oxygen atom is a
polar covalent bond
the of water molecules and the h bonds between water molecules explain most of waters life supporting properties
polarity
Within a plant, water (H2O) and carbon dioxide (CO2) can be combined (using the energy of sunlight) to produce glucose (C6H12O6) and oxygen (O2). If you were to write out this chemical reaction, water and carbon dioxide are each an example of a(n) while glucose and oxygen are each an example of a(n)
reactant product
chemistry
scientific study of matter
when one pair of electrons is shared between two atoms, a bond is formed
single
atom
smallest unit of matter that retain all of the physical properties of that type of matter
Water is a versatile
solvent
In addition to the risk of accidents, which of the following is a problem when nuclear power is used as a method of generating electrical power?
storage and disposal of spent fuel rods Submit
which best describes how charges are distributed on a water molecule
the o end is negative relative to the end with the two h atoms
which statement is true of pH buffers
they consists of weak acids and weak bases
which statement correctly describes hydrogen bonds
they hold together adjacent water molecules
which of the following are trace elements required by your body for proper health?
zinc molybdenum tin
