Chapter 2 Flashcards (Unit 1)
What is matter?
It refers to anything that takes up space and has mass
What are the three states that matter exists in?
Solid, Liquid, and Gas
What basic substance(s) is matter composed of?
Elements
What is an element?
It is a substance that cannot be broken down to simpler substances with different property
What two kinds of properties are there?
Chemica/Physical
How many naturally occuring elements are there?
92
What are the elemnts that are basic to life?
CHNOPS (Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorus, Sulfur)
What was John Dalton’s discovery?
Atoms
What is an atom?
It is the smallest unit of matter. Atoms make up elements, and display the properties of elements as well
What is the atomic symbol used for?
It is used to depict the name of the element
What are the subatomic particles inside an atom
Electrons, Protons, Neutrons
Where are the subatomic particles located?
Protons and Neutrons are located within the nucleus, Electrons move around the nucleus.
What is the electron shell?
It is the average location of the electrons
What does the atomic number represent?
The atomic number represents the number of protons/electrons within a particular element
What is the mass number of the atom dependent on?
It is dependent on the number of subatomic particles in that atom
What is the mass number?
It is the sum of protons and neutrons in the nucleus
Who developed the periodic table?
Dmitri Mendeleev
What is the atomic mass?
It is the average of the AMU for all of the isotopes of the atom
What are isotopes?
They are the atoms of the same element that differ in the number of neutronss
How can the radiation that is given off by various radioactive isotopes be detected?
Geiger counter is an instrument that is commonly used
What is a tracer?
A small amount of radioactive isotope that is used to detect molecular changes
What is one medical application of highly radioactive substances?
Sterilization (like cleaning)
What is the bohr model in the electron?
The electrons shells about the nucleus also represent energy levels
What is the outermost shell called?
The valence shell
When does a compound exist?
A compound exists when two or more elements have bonded together
What is a molecule?
The smallest part of a compound that still has the properties of the particular compound
What information does a formula give?
It tells you the number of each kind of atom in a molecule
What do spontaneous chemical reactions release?
They release energy
What is an ion?
It is a partice that has a charge (due to electron transfer)
What is an ionic bond?
It is the bond between a negatively and positively charged ion
What is a covalent bond?
It is a bond that occurs when two atoms share electrons in such a way that each atom has an octet of electrons in the outer shell
How many electrons does hydrogen require to complete it’s outer level?
2
When does a non polar occur?
When the sharing of electrons between two atoms (in a covelent bond) is equal
What is electronegativey dependent on?
On the number of protons-the greater the number of protons, the greater the electronegativity
What is a polar covalent bond?
It is a covalent bond in which the electrons are not shared equally
What is the shape of water/ all organic molecules necessary for?
It is necessary to the strutural and functional roles they plan in living things (Lock-key)
What is a hydrogen bond?
The attraction of a slightly positive hydrogen to a slightly negative atom in the vicinity
What are some properties of water? (list 4)
- It has high heat capacity
- High heat of evaporation
- Water is a solvent
- Water molecules are cohesive and adhesive
What does water’s high heat of evaporation allow animals living in hot enviromnents to do?
It gives them a way to cool themselves
What is cohesion?
It is the ability of water to cling to eachother due to hydrogen bonding?
What is adhesion?
Refers tot he ability of water molecules to cling to other polar surfaces
Is frozen water more/less dense than liquid?
LEss
What are acids?
They are substances that dissociate in water, releasing hydrogen ions (H+)
The acidity of a substance depends on….
How fully it dissociates
What are some examples of acidic substances?
Lemon juice,vinegar, tomatoes, and coffee
What are bases?
They are substances that either take up hydrgen ions (H+) or relase hydroxide (OH-) ions
What are some examples of bases?
Milk of magnesia and ammonia
What is the pH scale?
It is used to indicate the acidity or basicity of a solution
How far does the pH scale run?
1-14
What is a buffer?
It is a combination of chemicals that keeps pH within normal limits
