Study Guide 3rd Quarter Exam

What is a hypothesis? a testable prediction

What are the steps of the Scientific Method? State the problem, research, hypothesis, test hypothesis, conclusion

Define independent and dependent variables and indicate which axis each is located on. independent-the variable you change to see how it will affect the dependent variable; X axis dependent- a factor that changes in an experiment from manipulation of the independent variable; Y axis

What type of graph should be used to show how the temperature changes over the course of one year? Line graph

Independent variable- amount of water John has three tomato plants. He waters them twice a day for two weeks and measures their growth daily. Each plant is the same size at the start of the experiment and the same type of soil is used for each plant. He gives Plant A 50 ml of water, Plant B 100 ml of water (recommended amount – used for comparison), and Plant C 200 ml of water twice daily. Identify the following: Independent variable- amount of water Dependent variable- growth of plant Control- plant B Constants frequency of watering, type and size of plants, soil type and amount Possible hypothesis: If plants receive the optimum amount of water, then they will grow the tallest.

Green plants convert light energy from the sun into what type of energy in the process of photosynthesis? chemical potential

Where does the energy that travels through Earth’s ecosystems come from? the sun

How do most cells release the energy stored in glucose? Cellular respiration

What is a food chain? the feeding relationships between a producer and a single chain of consumers

What is a food web? the feeding interactions of all the food chains in an ecosystem

What role do consumers play in a food web? consumers eat producers or lower level consumers to get energy from the sun

What role do producers play in a food web? Producers use carbon dioxide, water and sunlight to make sugars they store 

What happens to most matter when it is heated? The particles gain KE and break attractions to neighboring particles; they take up more space

What behavior of water is unusual? Water expands as it goes from liquid to a solid (most other substances contract) due to its polarity

Compare the speed of the particles in a solid compared to a gas. Particles move much slower (vibrate in place)

List the characteristics of a… solid Definite volume Definite shape Crystalline, orderly particle structure Particles held tightly in place Least amount of KE

List the characteristics of a… liquid Definite volume No definite shape More KE than a solid, but less than a gas Enough KE to escape orderly arrangement Can flow

List the characteristics of a… gas No definite volume No definite shape Most KE

Define a mixture. Give an example. a material made up of two or more substances that can be easily separated by physical means; salt water, pizza, trail mix

Define chemical change. Give an example. a change in which new substances are produced Ex>Rusty nail     

Define physical change. Give an example. a change in size, shape, or state of matter Ex>Melting an ice cube, ripping a sheet of paper in half

What do electron dot diagrams represent What do electron dot diagrams represent? Draw the electron dot diagram for H and Cl electrons in the outermost energy level

Why are the noble gases considered stable? They have a full outer energy level

Define: a. atomic number-the number of protons in an atom b Define: a. atomic number-the number of protons in an atom b. atomic mass-weighted average mass of all isotopes for an element c. mass number- protons +neutrons in the nucleus d. average atomic mass-weighted average mass of all isotopes for an element

What is an isotope? Give an example. Atoms of the same element with different numbers of neutrons. Ex> carbon-12, carbon-13, and carbon-14

Draw and label the parts of an atom and subatomic particles.

Water is a polar molecule. What does this mean? there is unequal sharing of electrons in bonds between atoms leading to regions of slight charge

How is a nonpolar molecule different than a polar molecule? There is equal sharing of electrons in nonpolar molecules

Slight positive cancels out the slight negative charge Ex> water Although some molecules have a slightly positive and a slightly negative end, the overall molecule is neutral. Explain why or illustrate why this is true. Slight positive cancels out the slight negative charge Ex> water

Why do atoms combine to make compounds? To achieve stability by filling valence shells with electrons

Give an example of the properties of a compound being different than the properties of the elements that make them up. Salt being formed from sodium and chlorine Copper sulfate being formed from copper, sulfur, and oxygen

When is an atom considered stable? When the outermost energy level is filled with electrons

What is a chemical formula? Give one example. Shows elements a compound contains and the exact number of the atoms of each in a unit of that compound Ex. H2O, NaCl

What is the difference between a covalent and ionic bond? Between metals and nonmetals Between nonmetals Transfer of electrons Form ionic compounds Sharing of electrons Form molecules

How many hydrogen atoms are present in one molecule of ammonium acetate, NH4C2H3O2? 7

What is the pH scale used for? To measure the concentration of H+ ions in a solution

If a substance has a pH of 1, is it a strong acid or a strong base?

Sugar is the solute and water is the solvent When sugar is dissolved in water to make a solution, which substance is the solute and which is the solvent? Sugar is the solute and water is the solvent

What is the difference between saturated and unsaturated fats? Saturated fats have all single bonds between carbon atoms in the fatty acid chains

How are polymers created from monomers (name the process)? Polymerization reactions (dehydration synthesis)

List the four macromolecules, the main function(s) of each, the monomer each is made of (or structure if no monomer is present), and an example of each. Macromolecule     Carbs Lipids   Nucleic Acids Proteins Function(s)  energy and structure  long term energy, insulation, structural(cell membrane)  encoding and transmitting genetic info  enzymes, transport in body, structural Monomer/ structure  monosaccharides (glucose) No monomer Nucleotides Anino acids Example  starch, glycogen Fats, oils, phospholipids DNA, RNA Hemoglobin, insulin

What makes carbon special? 4 valence electrons make it capable of forming many diverse compounds

How many bonds can carbon form? 4

When disaccharides are changed to monosaccharides, what chemical process is used? hydrolysis