Chemistry and Water Properties test Flashcards
What is matter?
Anything with mass and volume
What 4 elements make up 90% of the human body?
Oxygen, Carbon, Hydrogen, and Nitrogen
Atom
Smallest particle of an element
Nucleus
Central core of an atom with most of its mass- consists of protons and neutrons and is positively charged
All atoms of a given element have the same number of _______
Protons
Outermost energy level of electrons
Valence
Most elements combine with other elements to form what?
Compounds
In chemical reactions…
bonds are broken; atoms are rearranged and new chemical bonds are made
Covalent bonds
Formed when two atoms share one or more pairs of electrons
Ionic bond
Some atoms become stable by losing or gaining electrons
Nonpolar Covalent bond
Equal sharing of electrons
Polar Covalent bond
Unequal sharing of electrons
Water is a…
Polar Molecule (has oppositely charged ends)
Water molecules form ________ _____ between them
Hydrogen Bonds
Cohesion
Water molecules stick to each other (responsible for beading and surface tension)
Adhesion
Water molecules stick to other substances
Capillary Action
Water rises up a narrow tube- important for plants!
Water _______ ____. It is slow to _____ __ and _____ ____.
Retains heat, warm up, cool down
Water makes up ___ of our bodies and ___ of the Earth’s surface
60% and 75%
Water is called the “_________” ______ because it can dissolve so many other substances.
“Universal” solvent
Mixtures
Two or more substances combined (not chemically)
Suspensions
Substances that do not dissolve and particles may settle out (Heterogenous)
Solutions
Substances that dissolve in another substance and particles don’t settle out (Homogenous)
The dissolving substance in a solution
Solvent
The substance that is dissolved in a substance
Solute
Acid
Any chemical that releases H+ (hydronium) ions when dissolved in water
Base
Any substance that releases OH- (hydroxide) ions
Neutralization Reaction
When an acid and a base are combined, they produce two neutral substances (water and salt)
pH scale
Expresses H+ concentration in a solution. pH= “power of Hydrogen”
7- Neutral
Below 7- Acid
Above 7- Base
Each change in pH of one represents a change in strength of __ times
10
