Chapter 2 Flashcards
uniiverse is composed of
________
matter
Matter is found on Earth in what three physical states?
solid, liquid, and gas.
Define Matter
anything that exhibit:
– Inertia: resistance to change in position
– occupies space
– has mass
What is the difference b/w MASS and WEIGHT
MASS: how much matter is in an object
WEIGHT: how hard gravity pulls an object
What do we use to organize our understanding of
matter?
The periodic table of the elements
What is the fundamental unit of matter?
atoms
There are ___ naturally occurring elements, but only __ are typically used by living cells
92; 25
What are atoms?
the smallest units that retain all properties of their type of matter
T or F: All matter consists of chemical elements
T
Elements are listed in order of?
atomic number (# of protons)
Each atom of an element is composed of?
protons, neutrons, and electrons
T/F Your weight is same wherever you go
FALSE, your mass is the same wherever you go
When atoms are bonded together they form what?
stable molecules
The atomic weight of an element corresponds to?
of protons + # of neutrons
__ elements are required in small quantities (micronutrients), and
__ are required in only tiny amounts
7; 14
T/F Elements are essential to life
True
How many of the of the 92 known elements make
up the bulk (mass) of living cells and what are they?
- Oxygen
- carbon
- hydrogen
- nitrogen
what is the difference between micronutrients and trace elements?
micronutrients are required in small quantities while trace elements are required in only tiny amounts.
name the 7 micronutrients:
calcium
phosphorus
potassium
sulfur
sodium
chlorine
magnesium
What are the following elements considered as?
boron
chromium
cobalt
copper
fluorine
iodine
iron
manganese
molybdenum
selenium
silicon
tin
vanadium
zinc
Trace elements
*Located in nucleus
*The number of
_______ determines
the chemical element
protons
Nitrogen Atom:
7 protons
7 neutrons
7 electrons
What is the atomic weight?
Atomic weight = Protons + Neutrons
7 protons + 7 neutrons = 14
*Located in nucleus
- The number of
________ determines
the isotope
neutrons
T/F Ions vary in the number of electrons in the
electron cloud
True
define isotopes
variants of an element that
differs in their number of neutrons.
T or F Isotopes are less stable
and may decay over
time, emitting radiation
T
What happens when an atom loses electrons?
it becomes electrically charged
In a chemical reaction, atoms do what?
gain, lose, or share electrons
What are charged atoms called?
Ions (can be positive or negative)
Nitrogen Ion:
7 protons
8 neutrons
10 electrons
If a nitrogen atom gains 3 electrons, is it positively
or negatively charged?
Negatively charged (Anion)
What is it called when Electrons are arranged in electron shells corresponding to different energy level?
Electronic Configurations
involve the transfer of one or more electrons from one atom to another.
ionic bonds
define covalent bonds
involve the sharing of one or more electrons between atoms.
In ionic bonds, is the receiving atom positively or negatively charged? Donating atom?
Receiving: Negative
Donating: Positive
How are Ionic bonds held together?
by attraction of opposite
charges.
If a nitrogen atom gains 3 electrons, does it have a greater mass than before?
No, the mass is the same because electrons have no mass
1st orbital = can only take ___ electrons
2nd orbital = can take max of ___ electrons
3rd orbital = can take max of 8 electrons
4th orbital = can take max of __ electrons
5th orbital = can take max of __ electrons
1st orbital = can only take 2 electrons
2nd orbital = can take max of 8 electrons
3rd orbital = can take max of 8 electrons
4th orbital = can take max of 18 electrons
5th orbital = can take max of 32 electrons
what is the difference between polar and nonpolar covalent bonds?
nonpolar is the equal sharing of electrons while polar is the unequal sharing of electrons
What are the strongest of the chemical bonds?
Covalent bonds
Bonds formed between C, N, O, P, H, S in all macromolecules such as proteins,
carbohydrates, nucleic acids and lipids are
what type of bonds?
covalent bonds
which covalent bonds are stronger between polar and nonpolar?
Nonpolar because the electrons are shared equally
What do the polar covalent bonds
in water mean?
Uneven distribution charger
- Oxygen is more negative and hydrogens are more positive
In the polar covalent bond of water
what charge do oxygen and hydrogen have?
Oxygen is more negative
Hydrogens are more positive.
The weak attractions between polar molecules
Hydrogen bonds
Hydrogen bonds hold ______(code of Life) together.
DNA
The polar nature of water means that water forms what type of bonds?
hydrogen bonds
Why is water so suitable for life?
Unique properties make it solid, liquid, or gas
What happens as water freezes?
stable hydrogen bonds
hold molecules apart
In liquid water, hydrogen bonds
constantly do what?
break and re-form
Does a chunk of ice or an equal volume of liquid water have fewer water molecules?
A chunk of ice
T or F Chemical reactions can rearrange
matter but cannot create or destroy matter?
True
Which bonds are responsible for stable structures of proteins and nucleic acids?
Hydrogen bonds
Define Synthesis Reactions (Anabolism)
when atoms, ions, or molecules combine to form new, larger molecules
________ (what goes in) are transformed
into __________ (what comes out) through
__________ reactions.
reactants
products
water
Reactants and products are on what side of a chemical reaction?
Chemical reactions are written with the reactants on the left and the products on the right
what donates H+ (Hydrogen ion) when dissolved in water?
HCl = H+ + Cl-
Acids
What is the synthesis of molecules in a cell
Anabolism
A (atom, ion, or molecule A)
+
B (atom, ion, or molecule B)
=
AB (New molecule)
Is this a Synthesis or Decomposition rxn?
Synthesis
what accepts H+ when dissolved in water
and/or can increase the concentration of
OH- (hydroxyl ions?
NaOH = Na+ + OH-
bases
AB (New molecule)
=
A (atom, ion, or molecule A)
+
B (atom, ion, or molecule B)
What reaction is this?
Decomposition
when a molecule is split into smaller molecules,
ions, or atoms
Decomposition
*_________ is the decomposition reactions in a cell
catabolism
Zest and Sharpness of food flavor is often due to ______
acid
what does the pH scale measure?
Measures H+ concentration of fluid
How do scientists indicate
how strong or weak an acid or base is?
The pH scale
fill in below:
0———————7——————-14
______ ________ ________
0———————7——————-14
acidic neutral basic
Each number in the pH scale represents what?
tenfold change in H+ ion concentration
Change of 1 pH on scale means ___X change in H+ concentration
e.g. A change in pH from 8 to 10 = 100X stronger base
10X
Organic compounds ALWAYS contain what?
carbon and hydrogen
The amount of H+ in a solution is expressed as what?
pH
what is the pH equation?
pH = −log[H+]
What do inorganic molecules lack?
carbon
Increasing [H+], increases _____
Increasing [OH−] increases ________
acidity
alkalinity
How are polymers made?
by stringing together many
smaller molecules called monomers
Most organisms grow best between pH of what?
6.5 and 8.5
are carbon-based molecules
organic compounds
What 2 things happens in a dehydration reaction?
- Links two monomers together
- Removes a molecule of water
all anabolic reactions are what?
dehydration
what process is this?
*Breaks bonds between monomers
* Adds a molecule of water
* Reverses the dehydration reaction
hydrolysis
