The Nature of Matter and Chemical reactions and Enzymes – Flashcards

Unlock all answers in this set

Unlock answers
question
What is an atom?
answer
the study of chemistry begins with the basic unit of matter
question
What would you say about the appearance of an atom?
answer
incredibly small, an atom contains subatomic particles that are even smaller
question
what are the subatomic particles that make up atoms?
answer
protons, neutrons, and electrons
question
what are the charges of protons and neutrons?
answer
protons (+) and neutrons carry no charge
question
What is the nucleus?
answer
strong forces bind protons and neutrons
question
what is a negatively charged particle?
answer
electron
question
where are the electrons?
answer
constant motion in the space surrounding the nucleus
question
what are electrons attracted to?
answer
attracted to the positively charged nucleus but remain outside the nucleus because of the energy of their motion
question
what makes some atoms neutral?
answer
atoms have equal numbers of electrons and protons and because these subatomic particles have equal but opposite charges, atoms are neutral
question
what is an element?
answer
a pure substance that consists entirely of one type of atom
question
what is the number of protons in an atom represented by?
answer
atomic number
question
what are isotopes?
answer
atoms of the same elements that differ in the number of neutrons
question
what is the sum of the protons and neutrons in the nucleus of an atom called?
answer
mass number
question
how are isotopes identified?
answer
mass numbers
question
what is the weighted average of the masses of an element's isotopes called?
answer
atomic mass
question
what does "weighted" mean?
answer
the abundance of each isotope in nature is considered when the average is calculated
question
what does it mean for all isotopes when they have the same number of electrons?
answer
the same chemical properties
question
what does it mean that isotopes are radioactive?
answer
their nuclei are unstable and break down at a constant rate over time
question
List different ways how radioactive isotopes can have important scientific d practical uses
answer
geologists can determine the ages of rocks and fossils by analyzing the isotopes found in them. radiation from certain isotopes can be used to treat cancer and to kill bacteria that cause food to spoil. It can also be used as labels or tracers to follow the movements of substances within organisms.
question
what is a compound
answer
a substance formed by the chemical combination of two or more elements in definite proportions
question
how do scientists show the composition of compounds?
answer
chemical formula
question
how can a compound differ from the elements that they are made from?
answer
physical and chemical properties can be different
question
how are atoms in compounds held together?
answer
chemical bonds
question
what are electrons that are available to form bonds called?
answer
valence electrons
question
what are the main types of chemical bonds?
answer
ionic bonds and covalent bonds
question
what is an ionic bond?
answer
formed when one or more electrons are transferred from one atom to another
question
what are ions?
answer
positively and negatively charged atoms
question
what forms when electrons are shared between atoms?
answer
covalent bond
question
what is the molecule?
answer
the structure that results when atoms are joined together by covalent bonds. the smallest unit of most compounds
question
Explain van der Waals forces
answer
when molecules are close together, a slight attraction can develop between the oppositely charged regions of nearby molecules. chemist called such intermolecular forces of attraction van der waals forces, after the scientist who discovered them. not as strong as ionic bonds or covalent bonds, they can hold molecules together especially when the molecules are large
question
what is a chemical reaction?
answer
a process that changes, or transforms, one set of chemicals into another
question
what is an important scientific principle?
answer
mass and energy are conserved during chemical transformatinons
question
what are reactants?
answer
elements or compounds that enter into a chemical reaction
question
what are products?
answer
elements or compounds produced by a chemical reaction
question
chemical reactions always involve in what changes?
answer
changes in the chemical bonds that join atoms in compounds
question
what is one example of an important chemical reaction that occurs in your body?
answer
carbon dioxide
question
where is the carbon dioxide carried to in your body?
answer
lungs through the bloodstream, and not very soluble in water. the bloodstream could not possibly dissolve enough carbon dioxide to carry it away from your tissues were it not for a chemical reaction. as it enters the blood, carbon dioxide reacts with water to produce a highly soluble compound called carbonic acid.
question
what is released or absorbed whenever chemical bonds form or are broken?
answer
energy
question
because chemical reactions involve breaking and forming bonds, they involve changes in what?
answer
energy
question
what is one of the most important factors in determining whether a chemical reaction will occur?
answer
energy changes
question
what could say about chemical reactions that release or absorb energy?
answer
chemical reactions that release energy often occur spontaneously. chemical reactions that absorb energy will not occur without a source of energy
question
what is an example of an energy releasing reaction?
answer
hydrogen gas burning, or reacting, with oxygen to produce water vapor
question
what is energy released in the form of?
answer
heat and sometimes hydrogen gas explodes, light and sound
question
in order to stay alive, organisms need to carry out what?
answer
need to carry out reactions that require energy
question
because matter and energy are conserved in chemical reactions, every organism must have what to carry out chemical reactions?
answer
must have a source of energy to carry out chemical reactions
question
humans release the energy to grow tall, to breathe, to think, and even to dream through the chemical reactions that occur when humans what?
answer
metabolize, or break down, digested food
question
what do chemists call the energy that is needed to get a reaction started?
answer
activation energy
question
Some chemical reactions that make life possible are too slow or have activation energies that are too high to make them practical for what?
answer
living tissue
question
what is a catalyst?
answer
a substance that speeds up the rate of a chemical reaction
question
how do catalysts work?
answer
by lowering a reaction's activation energy
question
what are enzymes?
answer
proteins that act as biological catalysts
question
what do enzymes speed up?
answer
chemical reactions that take place in cells
question
your bloodstream contains an enzyme called what?
answer
an enzyme called carbonic anhydrase that speeds up the reaction by a factor of 10 million. the reaction thakes place immediately and carbon dioxide is removed from the blood quickly
question
why are enzymes very specific?
answer
they generally catalyzing only one chemical reaction. for this reason, part of an enzyme's name is usually derived from the reaction it catalyzes.
question
carbonic anhydrase gets its name because it?
answer
catalyzes the reaction that removes water from carbonic acid
question
how does a chemical reaction take place?
answer
for a chemical reaction to take place,the reactants must collide with enough energy so that existing bonds will be broken and new bonds will be formed.
question
what happens when reactants do not have energy?
answer
unchanged after the collision
question
what provides a site where reactants can be brought together to react?
answer
enzymes, such a site reduces the energy needed for reaction
question
what are reactants of enzyme-catalyzed reactions known as?
answer
substrates
question
enzymes help do what in your body?
answer
help digest food,work best at certain pH values.
question
what are enzymes affected by?
answer
any variable that influences a chemical reactions. affected by changes in temperature.
question
at what temp. does enzymes work best at?
answer
37 degrees Celsius, the normal temperature of the human body
question
what can regulate the activities of enzymes in a variety of ways?
answer
cells, most cells contain proteins that help to turn key enzymes on or off at critical staes in the life of the cell.
question
enzymes play essential roles in what?
answer
regulating chemical pathways, making materials that cells need, releasing energy, and transferring information.
Get an explanation on any task
Get unstuck with the help of our AI assistant in seconds
New