Unit 1: Chemistry Flashcards
What are the 9 steps of the scientific method?
- Observe the world around
- Ask questions, privides frame work of experiment
- Research
- Hypothesis
- Experiement
- Collect data
- Analyze data
- Make a conclusion
- Do a follow up experiment
Properties of water
High or low specific heat?
High or low boiling point?
- high specific heat
- high boiling point
- liquid
Matter
Anything that has mass and volume
Element
A pure substance that cannot be broken down any further by ordinary chemical means
Atom
Smallest part of an element that still maintains the chemical and physical properties of that element
Compound
- 2 or more different elements chemically combined to form a new substance
- Can be separated into a simpler subtanvr only by chemical means
- Has properties that are different from the elements they are made from
Atomic number
# of protons Tells us what element it is
How do you find the number of electons?
The number of electrons=number of protons
Atomic mass
The weighted average of all the isotopes for a given element based on their frequency in nature
Valence electrons
Electrons that are found in an atom’s outermost energy level (furthest from the nucleus) these are important because they determine how an atom will bond and react
Group
Also called a family
VERTICAL columns on the periodic table
Elements in the same group have the same number of valence electrons and similar properties
Period
HORIZONTAL rows of the periodic table
Have the same number of energy levels
Covalent bonds
What types of atoms can covalent bonds form?
Formed when 2 atoms share electrons in order to satisfy the octet rule
There are no cations or anions because they are sharing electrons (no charge)
Formed from Nonmetals only
Polar covalent bonds
Atoms are NOT equally sharing electrons because one of the electrons is stronger
Partial charge due to unequal sharing
Nonpolar covalent bonds
Atoms are equally sharing electrons
No charge due to equal sharing
Polarity is the difference in _________ of the atoms bonded together
Electromagnetivity-the ability of an atom to pull electrons towards itself
Electromagnitivity for NPC, PC, and ionic
NPC-less than 0.5
Difference is greater than 1.7-ionic
Difference is greater than 0.5-polar covalent
pH
Power of hydrogen, measure of concentration of H+ ions
measure of acidity
Properties of acids
- sour taste
- changes litmus paper from blue to red
- has the ability to interact with bases to form neutral salts
- pH of 0-6 is acidic
Properties of bases
- another name for base is alkaline
- decreases the hydrogen ion concentration
- can increase the hydroxide ion concentration
- pH of 8-14
- bitter
- slippery
- turns litmus paper from red to blue
- reacts with acids to form saly and water
Why is water a polar molecule?
Because it has an unequal distribution of charges
In a water molecule, what are the oxygen and hydrogen atoms held together by? How do the whole water molecules stick together?
O and H atoms are held together by POLAR COVALENT BONDS
Water molecules are held together by HYDROGEN BONDS
How does a hydrogen bond work?
When a hydrogen atom is part of a Polar covalent bond, its partial + charge allows it to share attractions with other elctronegative atoms. The charged regions on H2O molecules are electrically attracted to oppositely charged regions on neighboring molecules. Since the + charged region in this type of bond is always a hydrogen atom, the bond is a hydrogen bond
How many hydrogen bonds can a H2O molecule have?
up to 4
