Chapter+Two

Dmitri Mendeleev BIOL 160: General Biology
 * CHAPTER 2: Life’s Chemical Basis**

Definition Worksheet #2: Chapter 2 Define the following key terms. 1. Atom: smallest unit of an element that still retains the properties of that element 2. Proton: positively charged subatomic particle in nucleus 3. Neutron: subatomic particle in nuclues of an atom with no charge 4. Electron: negative charge 5. Atomic Number: atoms differ in the number of subatomic particles, the number of protons 6. Atomic Mass: equals the average weight of the elements, proton & neutrons 7. Isotope: different numbers of neutrons forms 8. Ion: an atom that has either lost or gained one or more electrons & carries an electrical charge 9. Cation: positively charged ion (ca + ion) 10. Anion: negatively charged ion (a negative ion) 11. Molecule: two or more atoms of the same or different elements joined in a chemcial bond 12. Chemical Bond: interaction between atoms or molecules & allows the formation of polyatomic chemical compounds 13. Ionic Bond: bond formed by the attraction between two oppositely charged ions 14. Electronegativity: a chemcial property that describes the ability of an atom to attract electrons 15. Polar Covalent Bond: a covalent bond between atoms of differing electronegatives 16. Non-polar Covalent Bond: a covalent bond between atoms of the same electronegatives 17. Hydrogen Bond: a weak intermolecular force between hydrogen & a nearby strongly electronegative atom 18. Solution: a homogeneous mixture composed of two or more substances 19. Solute: a substance that is dissolved in a solvent 20. Solvent: a substance into which a solute is dissolved 21. Acid: a substance that releases hydrogen ions into solution 22. Base: a substance that takes hydrogen ions solution 23. Buffer: a weak acid or base that resists changes in pH 24. Salt: any compound that dissolves easily in water & releases ions other than hydrogen or hydroxide ions

**By: Zaynah Somani **

Characteristics of atoms
 * __CHAPTER 2__****: Basic Introduction to Chemistry**
 * Subatomic particle || Charge || Location || Mass ||
 * proton || +1 || nucleus || 1 AMU ||
 * neutron || 0 || nucleus || 1 AMU ||
 * electron || +1 || outside the nuclues || negligible ||

Recent discoveries have increased the number of naturally occurring elements from 92 to 94.

Since subatomic particles may be **charged**, they may attract or repel other subatomic particles. Please complete the below table, indicating how the below pairings of subatomic particles would behave (attract, neutral, repulsion).
 * Subatomic particle || Proton || Neutron || Electron ||
 * Proton || repulsion || neutral || attraction ||
 * Neutron || neutral || neutral || neutral ||
 * Electron || attraction || neutral || repulsion ||

What is an element? Pure substances each consisting only of atoms with the same number of protons.


 * Atomic Number= # of protons ||

The periodic table of elements has elements placed in a repeating pattern based on their //chemical properties// and how they react with other
 * 1.** **Periodic Table**

mass of protons + neutrons || elements. (Appendix 4 in the back of the book shows a periodic table.)
 * Atomic Mass=


 * Principle || Definition || C || N || O || P || Fl || Na ||
 * Atomic Number || # of protons || 6 || 7 || 8 || 15 || 9 || 11 ||
 * Atomic Mass || # of protons + neutrons || 12.01 || 14.07 || 16.00 || 30.97 || 19.00 || 22.99 ||
 * # of electrons || - || 6 || 7 || 8 || 15 || 9 || 11 ||
 * # of protons || - || 6 || 7 || 8 || 15 || 9 || 11 ||

2.What makes Carbon different than Hydrogen? because of protons, neutrons and electrons

3.What is an isotope? an atom of an element that differs in its number of neutrons, 12C ( six protons, six neutrons)

A. The element carbon has 3 main different isotopes: 12C has a mass of 12, due to __protons and__ neutrons : __6 protons, 6 neutrons__ 13C has a mass of 13, due to __protons and__ neutrons: __6 protons, 7 neutrons__ 14C has a mass of 14, due to __protons and__ neutrons: __6 protons, 8 neutrons__ B. Some isotopes have an unstable nucleus and may release energy or some of the subatomic particles (protons or neutrons) to become more stable. These isotopes are called __radioisotopes__. Some are used in medicine to “label” specific molecules or to follow a specific molecule as it is distributed throughout the body. In this case it is commonly called a __tracer.__ They may also release enough energy to kill cells and stop the activity of abnormal (cancer) cells, or the energy released may be used to drive an artificial pacemaker (helps the heart maintain a regular rhythm). 5. It is most important to know what the subatomic particles are, where they are located in an atom, and that atoms of different elements differ because they contain different numbers of protons. The number behind each elemental name represents the atomic mass for that atom. Complete the following table.
 * //Element// || //Symbol// || //Atomic Number// || //Atomic Mass// || //Number of Protons// || //Number of Neutrons// || //Number of Electrons// ||
 * Nitrogen-14 || __N__ || 7 || 14 || __7__ || __7__ || __7__ ||
 * Chlorine-35 || __Cl__ || __17__ || 35 || 17 || __18__ || __17__ ||
 * Oxygen-16 || __O__ || __8__ || __16__ || __8__ || __8__ || __8__ ||
 * Sodium-23 || Na || __11__ || __22.99__ || 11 || __12__ || __11__ ||
 * Sulfur-35 || S || __16__ || 35 || __16__ || __19__ || __16__ ||
 * Oxygen-17 || __O__ || __8__ || __17__ || __8__ || __9__ || __8__ ||

6. Complete the following matching activity.
 * A. || Radioisotope used to reveal the pathway or destination of a substance ||
 * B. || Subatomic particles with a negative charge ||
 * C. || Positively charged subatomic particles within the nucleus ||
 * D. || Subatomic particles within the nucleus carrying no charge ||
 * E. || Atoms of a given element that differ in the number of neutrons ||
 * F. || The number of protons in an atom ||
 * G. || Form of an element that emits radiation ||
 * H. || The number of protons and neutrons in the nucleus of one atom ||
 * I. || Pure substances, each consisting only of atoms with the same number of protons ||
 * J. || Smallest units of an element that retain the properties of a given element. Particles that are the building blocks of all substances. ||

1. __atoms:__ J __2.__ protons: C 3. __neutrons:__ D __4.__ electrons: B 5. __atomic number:__ F __6.__ atomic mass: H 7. __elements:__ I __8.__ isotope: E 9. __radioisotopes:__ G __10.__ tracer: A


 * By: Zaynah Somani **

7. Chemical Bonds Which subatomic particle participates in bonding between atoms? Electrons How do you figure out how many electrons there are in an atom? THE NUMBER OF ELECTRONS IS THE SAME AS THE NUMBER OF PROTONS. IT IS THE ATOMIC NUMBER. B. Each horizontal row on the periodic table represents an energy level around the nucleus of an atom. 1.The first level is closest to the nucleus and can hold only 2_ electrons due to its small volume and the fact that electrons repel each other. Electrons in this level have the **lowest amount of energy**. Notice that the top row on the periodic table has only two elements (H and He) and the atomic number of Helium is 2 which means it has 2 protons and 2 electrons. 2. The second level is farther away from the nucleus, so is larger in volume and can hold a __maximum__ of 8_ electrons. Notice that the second row on the periodic table has a total of eight elements and the atomic number for Neon the last element on the row is 10; which means a neutral Neon atom has 10 protons and 10 electrons (two of the electrons are on the first energy level and the remaining 8 electrons on the second level). 3. The third level is still farther away from the nucleus, so is able to hold more electrons than the second level, and the fourth level more than the third, etc. The problem is that not all of these additional electrons are located on the outermost energy level. C. **The atomic number on the periodic table equals the __total__ number of protons inside the nucleus and therefore the __total__ number of electrons found moving around the nucleus in an atom**; however it is **only those electrons on the outer energy level that are taken, shared or given away when atoms interact with other atoms**. The maximum number of electrons that can exist on the outer energy level of __any__ atom is __ALWAYS__ eight (except for H and He where the maximum number is two). Try to remember that “eight is great”. For the purposes of this class and to best prepare you for Anatomy and Physiology, it is necessary to “simplify” chemistry and the periodic table. It will be easier to understand how atoms behave if you pretend that the center (and bottom) of the periodic table don’t exist. Those elements in the middle of the periodic table have additional electrons that are NOT placed in the outer most energy level, therefore they do NOT influence how an atom of that element behaves.

D. **Where** the elements are found on the periodic table will help determine how an atom will interact with other atoms (“take”, “share” or “give away” some of their electrons). The **vertical** column of the periodic table indicates **the number of electrons** an atom of that element has in the outermost energy level. As mentioned, **it is only these outermost electrons that will influence how an atom interacts with other atoms as they form molecules**. E. Those elements in the last column on the periodic table (farthest to the right, or in column #8) are the most “stable” of all the elements, having just the right number of electrons to “fill” the outer energy level. These elements are very stable and normally do not react chemically with the other elements to form molecules. (Called the Inert Gases) F. All the other elements on the periodic table “wish” they could have the same number of electrons as one of those in column #8 (farthest to the right) so they too can become very stable. They do this by taking, giving or sharing electrons to fill their outer electron shell. The ability of an atom to “pull or take” electrons from another atom to become more stable is called ELECTRONEGATIVITY. 1. Those elements on the **right** side of the periodic table are so close to the last column, they tend to have **high electronegativity** values and tend to “TAKE” electrons from other elements until they have a total of 8 in their outer energy level or in some cases they may be forced to share electrons with other atoms. Using the periodic table as a guide, how many more electrons do atoms of the following elements need to take or share to reach a total of those in the last column? P =, Cl = , O = , N = , S = , C = , Br =
 * If this is the case, then all of the horizontal rows on the table will have eight columns**, except the first horizontal row which will have only two columns.

2. Those elements on the **left side** of the periodic table are far away from the last column, they tend to have **very low electronegativity** values and do NOT “pull or take” electrons from other atoms, in fact they **tend to “GIVE AWAY”** their electrons that are on the outer energy level to other atoms. In a sense they go backwards on the table until they reach the last column but on the row above where they started. Using the periodic table as a guide, how many electrons do atoms of the following elements **need to give away or lose** to revert back to the end of the previous level on the periodic table? Na =, Al = , Ca = , K = , C = , Mg = ,

G. Neutral atoms that “take” or “give away” electrons no longer remain neutral; they become either negatively or positively charged particles called IONS__. There are two main types:__ __1. ANIONS are those that have a negative charge because the neutral atom has “taken” electrons from other atoms so they now have more electrons than protons.__ __2. CATIONS are those that have a positive charge because the neutral atom has “given away” electrons to other atoms so they now have fewer electrons than protons.__ __8. When atoms “give away”,” take” or “share” electrons with other atoms they form a__ __CHEMICAL BOND__ (a force between two atoms that holds them together). A. MOLECULES_ are two or more atoms that have joined together to form a group. Some only contain one type of element: H2, O2, N2, F2, Cl2, Br2 & I2, but the majority contain two or more different types of elements. When a molecule contains two or more different elements combined in a fixed ratio (proportion) that never varies it is called a COMPOUND __. Examples include: water (H2O), Carbon dioxide (CO2), Hydrochloric acid (HCl), and Glucose (C6H12O6). The numbers in the chemical formulas indicate the number of atoms of each type in the molecule.__ __B.__ COMPOUNDS___ contain two or more substances (elements or compounds) that are combined together in a ratio (proportion) that **varies.** They can either be concentrated or dilute (as in strong or weak coffee). These forms of matter will be studied in much more detail in future modules. 9. There are several important chemical bonds seen in biological molecules. A.IONIC BONDS: oppositely charged ions held close by attraction, electrons transferred (one loses, one gains) between atoms
 * Element Location || Giver? Taker? || What type of ion formed? || Positive or negatively charged ion? ||
 * Left side of per table || GIVER || CATION || POSITIVE ||
 * Right side of per. table || TAKER || ANION || NEGATIVE ||

DONE BY KAREN K

1. Chemical formulas represent the **type and number of atoms** present in the compound. The number of atoms needed to keep the molecule neutral is dependent on the ion charges. Elements that “give away” one electron form +1 ions, those that “give away” 2 electrons form +2 ions, etc. Elements that “take” one electron form -1 ions, those that “take” 2 electrons form -2 ions, etc. Some examples of chemical formulas for ionic compounds include: Sodium chloride: NaCl This compound contains Na+1 and Cl-1 ions in a 1:1 ratio since their ion charges are the same value (+1 / -1) and they cancel each other out when forming a neutral atom. Magnesium nitride: Mg3N2 This compound contains Mg+2 and N-3 ions in a 3:2 ratio since their ion charges do not directly cancel each other out; three Mg+2 ions are needed to make a total of +6 charge, which is cancelled out by two N-3 ions that make a total of -6 charge forming a neutral molecule. B. COVALENT BONDS: 1.What is a covalent bond?

2.Atoms with (similar, differing) electronegativities form covalent bonds.

Covalent Bond ||
 * Covalent Bond || # of electrons shared? || Example || Structural Formula || Strength ||
 * Single ||  ||   ||   || Strong ||
 * Double ||  ||   ||   || Stronger ||
 * Triple ||  ||   ||   || Stronger yet! ||
 * Between two identical atoms || 2 || H2 ||  || NONPOLAR Covalent Bond ||
 * Between two different atoms || 4 || H2O ||  || POLAR

More electrons in Oxygen, so that part of the molecule is more negatively charged; fewer electrons near Hydrogens, so that part of the molecule is less negatively charged ||
 * POLAR COVALENT BOND

3. Covalent bonds are the strongest type of all chemical bonds. They are very difficult to break, and hold atoms together to form molecules. These bonds are also called INTRAMOLECULAR forces, because they exist within the molecule. 4. Chemical formulas of compounds that have covalent bonds are determined much the same way that ionic compounds are determined; however both atoms want to “take” electrons from each other. The number of atoms needed to keep the molecule neutral is dependent on the number of electrons they need to be like elements in column #8 on the periodic table. Some examples of chemical formulas for covalent compounds include:
 * Water (H2O) || # of e-s in outer shell || What combo would form an outer shell with 8 e-s? || Draw molecule ||
 * Hydrogen ||  ||   ||^   ||
 * Oxygen ||  ||   ||^   ||
 * Carbon Dioxide (CO2) || # of e-s in outer shell || What combo would form an outer shell with 8 e-s? || Draw molecule ||
 * Carbon ||  ||   ||^   ||
 * Oxygen ||  ||   ||^   ||

C. HYDROGEN BONDS: 1. What is a hydrogen bond? A hydrogen bond is a weak attraction between a highly electronegative atom and a hydrogen atom taking part in a separate polar covalent bond.

2. Are hydrogen bonds weak or strong attractions? Hydrogen bonds are weak. They form and break much more easily than covalent or ionic bonds.

7.Water’s Life-Giving Properties This illustration shows how hydrogen bonds collectively stabilize water molecules. How does this affect the unique physical properties of water? Each of the atoms in a water molecule caries a slight charge. the oxygen atom is slightly negative and the hydrogen atom is slightly positive.

a. Water is a molecule held together with POLAR COVALENT BONDS. Draw a picture of a water molecule, and explain how the oxygen and hydrogens participate in this type of bond.

b. Which part of a water molecule is slightly negative? The oxygen molecule.

c. Which is partially positive? The hydrogen molecule.

d. How does this affect interaction with other nearby molecules of water? Or other types of molecules? This separation of charge means a water molecule is polar. the polarity of each water molecule attracts other water molecules, and hydrogen bonds form between them in tremendous numbers.

e.Why does water have such a high surface tension? It's hydrogen bonds collectively exert a continuous pull on the individual water molecules. this pull is so strong that the molecules stay together rather than spreading out in a thin film as other liquids do.

f. What is a solvent? A solvent is a substance, usually a liquid, that can dissolve other substances.

g. Why is water such a good solvent? Clusters of water molecules form around the solutes in cellular fluids, tree sap, blood, the fluid in your gut, and most other fluids associated with life.

Positive ions attract the negative part of part of water (the oxygen atom), while negative ions attract the positive part of water (the __hydrogen atoms).__ __h. Water’s Temperature-Stabilizing Effects:__ __What is temperature?__ Temperature is a way to measure energy of this molecular motion.

__Why is it hard to change the temperature of water?__ Evaporation. It takes heat to convert liquid water to a gas, so the surface temperature of water decreasing during evaporation. __i.Water’s Cohesion:__ __What is cohesion?__ Cohesion means that the molecules resist separating from one another.

__How does the cohesion of water molecules help transport water up inside of the tissues of plants?__ water molecules evaporate from leaves, and replacements are pulled upward from roots.

__11. Dissolved ions inside of our bodies influence its structure and function. One of the body’s most chemically active ion is the hydrogen ion (H+1).__ __A.__ Acids are substances that release or donate hydrogen ions (H+1) to a water (aqueous) solution. **Remember that a hydrogen ion is the same thing as a //proton// since it is a hydrogen atom that has lost its electron**//.// 1. Strong acids ionize completely releasing their hydrogen ions easily. One example is Hydrochloric acid (HCl) found in the stomach. 2. Weak acids may have hydrogen ions to release to solution, but are reluctant or resistant to do so. One example is Carbonic acid (H2CO3) found in soft drinks that is formed when carbon dioxide reacts with water. B. Bases __are substances that accept or bond with hydrogen ions when dissolved in water solutions, thereby removing them or decreasing the number of hydrogen ions remaining in solution. They may also release hydroxide ions (OH-1) to a solution that will then combine with hydrogen ions to form water. These solutions are also known as //alkaline// solutions. This is how //Alka Seltzer// got its name. It reduces the acidity of the stomach when someone has acid indigestion.__ __C. The__ PH SCALE is used by scientists to represent the nature of a solution relative to the amount of hydrogen ions in solution. The scale extends from a numerical value of 0 __to__ 14. 1. Solutions with a value of “0” are very acidic_, meaning there is a high concentration of hydrogen ions in solution. 2. Solutions with a value of “14” are very low acidity (alkaline), meaning there is a very low concentration of hydrogen ions in solution. 3. Pure water has a value of __7, which indicates it is a neutral solution, or in other words one with the same amount of H+1 and OH-1 ions.__ __4. The pH scale is a type of metric scale. This means that for every change in the pH, there is a ten-fold change in the concentration of hydrogen ions. On the metric scale, to change from one unit of measurement to another it is necessary to move the decimal point either to the right or to the left. Each time the decimal point is moved it is equal to multiplying or dividing by 10. If the decimal moves 3 places to the right it is equal to multiplying the value by 10 X 10 X 10 or the final answer is 1,000 times larger. The following are several examples:__ __A solution with a pH = 2 is 10 times more acidic than a solution of pH = 3.__ __A solution with a pH = 5 is 100 times less acidic than a solution of pH = 3.__ __A solution with a pH = 10 is 100 times more basic than a solution of pH = 8.__ __A solution with a pH = 6 is 1000 times less basic than a solution of pH = 9.__ __D.__ __Salt_ are substances that when dissolved in water release ions other than the hydrogen ion (H+1) or hydroxide ion (OH-1). Examples include sodium chloride or table salt (NaCl) and calcium phosphate [ Ca3(PO4)2 ] found in bones. Most salts serve key functions in cells. The ions released into solution in the body are also called “electrolytes”, in that they allow the solution to be able to conduct an electric current.__ __E.__ buffer systems are substances that resist a change in pH when an acid or base is added to the solution. They are generally formed by mixing a weak acid and weak base. If a strong acid is added to the mixture, the weak base bonds to the hydrogen ions to neutralize the acid; if a strong base is added to the mixture, the weak acid releases hydrogen ions to neutralize the base. In either case, the pH does not change significantly. Buffers can only work for so long, then the pH will shift rapidly.

12. Give the approximate pH of each of the following solutions then identify each as an acid (A) [pH of 1-6], base (B) [ph of 8-14] or essentially neutral (N) [pH of 6-8].

1. Tomato juice 4 __2. Human blood__ 8 3. Vinegar 2 __4. Pure water__ 7 5. Coffee 5 __6. Ammonia__ 11 7. Seawater 8 __8. Typical rainwater__ 2 9. Oven / Drain cleaner 13/14 __10. Antacid pills (Tums)__ 9 11. Urine 5 __12. Gastric juice__ 1

= =

By: Shilla Hashimi
 * 13. Complete the following matching**

= =
 * 1. acid stomach N || A. || A sometimes irreversible state of unconsciousness ||
 * 2. acids **K** || B. || CO2 builds up in the blood, too much H2CO3 forms, and blood pH severely decreases ||
 * 3. pH scale **F** || C. || Hydroxide ion ||
 * 4. chemical burns **J** || D. || Substances that accept H+ when dissolved in water ||
 * 5. H+ **H** || E. || An uncorrected increase in blood pH ||
 * 6. bases **D** || F. || Used to measure H+ concentration in various fluids ||
 * 7. examples of basic solutions **I** || G. || A partnership between a weak acid and the base that forms when it dissolves in water; counters slight pH shifts ||
 * 8. coma **A** || H. || Hydrogen ion or proton ||
 * 9. Respiratoryacidosis **B** || I. || Baking soda, seawater, egg white ||
 * 10. OH– **C** || J. || Can be caused by ammonia, drain cleaner, and sulfuric acid in car batteries ||
 * 11. tetany **M** || K. || Substances that donate H+ when dissolved in water ||
 * 12. examples of acid solutions **L** || L. || Lemon juice, gastric fluid, coffee ||
 * 13. alkolosis **E** || M. || A potentially lethal pH stage in which the body’s skeletal muscles enter a state of uncontrollable contraction ||
 * 14. buffer system **G** || N. || Can be caused by eating too much fried chicken or certain other foods ||

Chapter review: Answer the following essay questions.

14. a. If a sulfur atom has six electrons in its outer shell of electrons, how many covalent bonds is it likely to form with other atoms? Why? Sulfur will fill its outer shell if it shares with two other molecules (like Hydrogen Sulfide, each hydrogen has one to share) or if it makes S2, it will just make a double bond with itself.

b. If a hydrogen atom has one electron in its outer shell of electrons, how many covalent bonds is it likely to form with other atoms? Why? One, A single hydrogen atom only has one electron so it can only make one bond.

c. What do you think the chemical formula for hydrogen sulfide would be? H2S

Hint: Look at the location of sulfur compared to oxygen on the periodic table.

15. In your own words, explain the main difference between a polar covalent bond and a nonpolar covalent bond.

Polar covalent bonds involve unequal sharing of electrons. Thus, there is a dipole moment within these molecules or areas of partial positive and partial negative charge. This is due to the unequal sharing of electrons, one atom has more than 50% of the negative charge. Water is an example of a molecule with polar covalent bonds.

Nonpolar covalent bonds occur when there is EQUAL sharing of electrons in a molecule. They often exist between two of the same elements, but they may exist between differing elements such as hydrocarbons or methane in which the areas of electron density are the same overall in the molecule. These compounds are hydrophobic, meaning they don’t dissolve in water.

16. If a water molecule is neutral (has no net charge), then why does it attract polar molecules and repel nonpolar ones.

Water attracts polar molecules because the area of greatest electron density in water (near the oxygen) is attracted to positively charged substances or other polar molecules on their positive end, and the area of lesser electron density on water (near the hydrogen) is attracted to others’ negatively charged ions or areas of greater electron density. Remember that opposites attract.

17. Explain why sweating helps cool the body when it is overheated?

Because sweat evaporates off the skin and that helps you cool down (in others words wiping it off will make you hotter.) sweating regulates body temperature

1. A substance that cannot be broken down into simpler substances by ordinary chemical means is known as a(n) a. molecule b. ion c. element d. compound e. isotope
 * //Sample Test Questions for chapter 2 and Lab #6://**

2. A sulfur atom has 6 electrons in its outer energy shell. As a result, it tends to form __covalent bonds with other atoms.__ __a. 2__ __b. 3__ __c. 4__ __d. 6__ __e. 8__

__3. A phosphorus atom has an atomic mass (mass number) of 31 and an atomic number__ __of 15. How many PROTONS are there in a neutral phosphorus atom?__ __a. 15__ __b. 16__ __c. 31__ __d. 46__ __e. none of the above__ __4. A__ __is a subatomic particle that carries a__ __charge.__ __a. proton……negative__ __b. electron…..negative__ __c. neutron…..negative__ __d. proton…..neutral__ __e. electron……neutral__

__5. Isotopes of an element differ in their number of:__ __a. electrons__ __b. bonds formed by the atom__ __c. protons__ __d. neutrons__ __e. nuclei__

__6. When hydrogen atoms lose one electon to become an ion, their net electrical charge is__ __a. +1__ __b. -1__ __c. remains neutral__ __d. impossible to know from just this information provided__ __BIOL 160: Module 1 - 28 -__

__7. A solution at pH of 4 contains__ the concentration of Hydrogen ions as the same amount of a solution with a pH of 2. a. 2 times more b. 2 times less c. 20 times more d. 20 times less e. 100 times less

8. This property of water makes it possible for columns of liquid water to rise from roots to leaves inside narrow pipelines of vascular tissues inside a plant. a. cohesion b. temperature c. water sickness d. surface tension e. none of the above

9. Bonds that form when atoms transfer one or more electrons are called __bonds.__ __a. ionic__ __b. polar covalent__ __c. hydrogen__ __d. non-polar covalent__

__10. Within water molecules, the hydrogen atoms are bonded to the oxygen atom by__ __bonds, whereas the hydrogen atoms form__ ___ bonds with neighboring water molecules. a. hydrogen…..ionic b. ionic……hydrogen c. polar covalent…….ionic d. polar covalent……hydrogen e. hydrogen…….polar covalent

11. A //solvent// is a. the dissolving agent of a solution b. generally the liquid portion of a solution c. usually water in living organisms d. generally the portion of a solution found in smaller amount e. A, B and C are all correct

12. If a sample has a mass of 0.08 grams, what is this mass measured in milligrams? a. 0.00008 b. 0.008 c. 0.08 d. 8.0 e. 80

By: Shilla Hashimi