Chapter 2 Test Study Guide Flashcards
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Atoms
All matter is made of atoms everything that occupies space and has mass. Atoms are the smallest unit of matter: it cannot be broken, has a nucleus in the center with energy levels around the nucleus.
3 Subatomic Particles
Particles that make up atoms
Protons
In nucleus, positive charge
Neutrons
In nucleus, neutral charge
Electrons
Orbits nucleus/Energy levels, negative charge
Elements
Pure substance that consists of one type of atom (many of the same atoms bonded together make an element)
5 Most common in the human body:
Carbon
Nitrogen
Hydrogen
Oxygen
Phosphorus
Identified by the number of protons (and how they are organized on the Periodic Table)
EX: Atomic number: 3. Element Symbol: Li. Atomic Mass: 6.94
What does the Atomic # tell us?
How many protons are in an element
How do we find the # of protons?
In the atomic number
What is the maximum number of electrons in the first energy level surrounding the nucleus?
2
What is the maximum number of electrons in the second energy level surrounding the nucleus?
8
What is the maximum number of electrons in the third energy level surrounding the nucleus?
18
What are chemical compounds?
A combo of 2 or more elements, when combined, compounds become their own unique substance. (the properties of compounds are different from the elements that form them).
What is an ionic bond?
Ionic Bonds: Transfer electrons from one element to another.
What is a covalent bond?
Covalent Bonds (valence electrons: the electrons in the outermost orbit): Share electrons between atoms.
What do the bonds have in common?
Both are strong bonds.
What is a water molecule made of?
Two hydrogen and one oxygen
What charge does the O atom in water have?
A negative charge
What is the charge of The H atoms in water
A positive charge
Water is a polar molecule. What does that mean?
There is an unequal distribution of charges in a water molecule
Where does the Hydrogen bond form between water molecules?
Attracting to oxgyen molecules
What are the life-giving properties of water
Universal Solvent, Adhesion, Less Dense as a Solid, Cohesion, High Specific Heat
Universal Solvent + its benefit
the polarity of water helps many substances dissolve in water. benefit: water can dissolve and transport + vitamins, nutrients, and minerals wherever it goes. solvent: substance doing the dissolving. solute: substance being dissolved. oil and water do NOT DISSOLVE well together.
Adhesion + its benefit
the attraction of molecules of a different kind. benefit: allows water to move from the roots to the top of a plant
Less Dense as a Solid + its benefit
water molecules are less tightly packed when frozen (solid) than when a liquid. benefit: lakes and ponds freeze from freezing by insulating them from freezing air temps
Cohesion + its benefit
the attraction of molecules to other molecules of the same kind. benefit: allows water to move from the roots to the top of a plant
High Specific Heat + its benefit
the amount of heat that must be absorbed or lost for water to change 1 degree C. Benefit: allows aquatic organisms to maintain homeostasis by regulating body temp, allows humans to live by regulating air temp
What are heterogenous and homogeneous mixture?
Heterogeneous: Visibly different substances or phases. ex: water + ice, salad dressing, salad.
Homogeneous: Same uniform appears throughout. ex: water, jello.
What is a pH scale?
Water dissociates when mixed with an acid or base (water separates and breaks down). When acids dissolve in water, they release H+ ions.
What does a pH scale measure?
Measures the concentration (neutral water) of hydrogen ions (H+)
What are characteristics of acids?
- Have a pH < 7
- More acidic
- Tastes sour
- Have a high concentration of H+ ions
What are characteristics of bases?
- Have a pH > 7
- The higher the pH, the more basic they are
- Tastes more bitter
- Have a high concentration of OH ions (low H+ ions)
What are buffers?
Helps keep the pH of the body constant by preventing sudden changes in pH (maintain homeostasis!!). Also helps organisms maintain the pH of body fluids within the narrow range acceptable for life. Ex: Tums.
