1matter
anything that takes up space and has mass
2mass
a measure of our energy content
3What four elements are the most abundant in living organisms?
carbon, hydrogen, nitrogen, oxygen
4Where did most elements come from?
supernovas (explosion of stars)
5atoms
made up of protons, neutrons, and electrons in an organized fashion
6atomic mass
depends on the number of protons and neutrons in the nucleus
7atomic number
indicates the number of protons of an element
8Where are protons and neutrons located?
in the nucleus
9Where are electrons located?
outside the nucleus constantly moving in a cloud shape
10What particles are the largest?
protons and neutrons
11What particles are the smallest?
electrons
12What is the importance of protons?
determines the atomic number, which gives each element a unique identity
13What is the importance of neutrons?
keeps the nuclei stable
14What is the importance of electrons?
responsible for how elements react
15isotopes
atoms of the same element with a different number of neutrons than protons in their nucleus that are unstable and emit radiation. the radiation is used for many medical procedures
16ions
have a differnt number of electrons than protons, and thus an electrical charge (charged atoms)
17What atomic particle is involved with bond formation?
electrons
18What are ionic bonds?
when two atoms are held together by the attraction between opposite charges
19What are covalent bonds and what is shared?
two atoms share electrons in order to have a completed outer shell
20Why are covalent bonds a very strong bond type?
it holds atoms together. a lot of energy is needed to break them
21What is a stronger bond H-H or O=O?
O=O, the more lines there are the more bonds there are
22What is a hydrogen bond?
weak interaction between hydrogen atom and highly electronegative atom
23molecule
when two or more atoms are bonded covalently
24compound
if the molecule contains more than one element
25reactants
molecules that participate in reactions (on left side)
26products
molecules formed by reactions (on right side)
27What are the properties of water?
is a solvent, is cohesive and adhesive, has high surface tension, maintains a temperature compatible with life, as a solid it is less dense than as a liquid
28Living organisms are made up of how much water?
70-90%
29Why is water a solvent?
because of its high polarity and hydrogen bonding
30What is cohesive?
ability of water molecules to cling together due to hydrogen bonding
31What is adhesive?
ability of water molecules to cling to other polar surfaces
32How does sweat cool the skin?
heat is released as sweat evaporates
33Why does steam burn?
steam has more heat absorbed from the vaporization and when it touches the skin it turns back to liquid and releases energy which leads to very severe burns
34acidic solutions
have high hydrogen ion (H^+) concentration
35basic solutions
release hydroxide ions (OH^-)
36What does it mean when the pH of substance is below 7, above 7, or at 7?
the lower the pH the more acidic the solution, the higher the pH the more basic the solution. pH of 7 is considered neutral (like water).
37buffers
important substances found in living organisms which help maintain a certain range of pH
38The product Tums is calcium carbonate, and acts as a buffer to stomach acid, how?
it dissolves which releases free hydrogen ions that are then consumed which leads to decreased hydrogen ion activity. it acts as a buffer to stomach acid by consuming hydrogen ions