BIO 163 Chemistry Lab PDF

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Chemistry lab...

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The Chemistry of Life Our exploration of the human body starts at the smallest level of organization: the chemical level. This chapter introduces you to basic principles of chemistry, which form the foundation for both our anatomy and our physiology.

What Do You Already Know? Before we take a journey into the unknown, it is a good idea to inventory what you already know—or at least what you think you already know. Try to answer the following questions before proceeding to the next section. If you’re unsure of the correct answers, give it your best attempt based on previous courses, previous chapters, or just your general knowledge. 1. What is the basic structure of an atom? 

Atoms consist of three basic particles: protons, electrons, and neutrons. The nucleus (center) of the atom contains the protons (positively charged) and the neutrons (no charge). The outermost regions of the atom are called electron shells and contain the electrons (negatively charged).

2. Which elements make up the human body? 

The human body is approximately 99% comprised of just six elements: Oxygen, hydrogen, nitrogen, carbon, calcium, and phosphorus.

3. What are the major macromolecules in the body? 

The four major classes of biological macromolecules are carbohydrates, lipids, proteins, and nucleic acids.

Module 2.1: Atoms and Elements Module 2.1 in your text introduces you to the chemical level of organization and the fundamental unit of chemicals, the atom. By the end of the module, you should be able to do the following: 1. Describe the charge, mass, and relative location of electrons, protons, and neutrons. 

Both protons and neutrons have a mass of 1 amu and are found in the nucleus. However, protons have a charge of +1, and neutrons are uncharged. Electrons have a mass of approximately 0 amu, orbit the nucleus, and have a charge of -1.

2. Compare and contrast the terms atoms and elements.

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An atom is the smallest component of an element, containing neutrons, protons, and electrons, and makes up everything around us. An element is a substance in which all of the atoms have the same atomic (proton) number. It is also defined as a substance which cannot be broken down by chemical means The common feature is that the atoms of all elements consist of electrons, protons, and neutrons.

3. Identify the four major elements found in the human body. 

The four most abundant elements in the human body – hydrogen, oxygen, carbon, and nitrogen

4. Compare and contrast the terms atomic number, mass number, isotope, and radioisotope. 

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The major difference between atomic number and mass number is that the atomic number states the number of protons present in an atom whereas, the mass number indicates the total of the number of protons and the number neutrons present in an atom. A Radioisotope is also an isotope by nature. The difference is that radioisotopes are very unstable and contain high levels of nuclear energy and emit this energy in the form of nuclear radiation. Main difference: Isotopes can be stable or unstable, but Radioisotopes are always unstable.

5. Explain how isotopes are produced. either form spontaneously (naturally) through radioactive decay of a nucleus

15 Build Your Own Glossary Use the glossary at the back of your book or look through the module to define the following terms. Key Terms for Module 2.1 Term

Definition

Matter

anything that occupies space and has mass

Chemistry

The study of the chemical substances and vital processes occurring in living organisms

Atom

smallest unit into which matter can be divided without the release of electrically charged particles

Proton

a positively charged particle that resides in the nucleus (the core of the atom) of an atom and has a mass of 1 and a charge of +1.

Neutron

an uncharged elementary particle that has a mass nearly equal to that of the proton and is present in all known atomic nuclei except the hydrogen nucleus.

Electron

a stable atomic particle that has a negative charge

Electron shell

the outside part of an atom around the atomic nucleus

Atomic number

the number of protons in an element

Element

A substance that cannot be decomposed into simpler substances by chemical means, and is made up of atoms all with an identical number of protons.

Mass number

The sum of the number of protons and the number of neutrons in an atom.

Isotope

members of a family of an element that all have the same number of protons but different numbers of neutrons.

Key Concept: What makes hydrogen unusual in its placement in the periodic table? 

Hydrogen has very small size consequently H+ does not exist freely and is always associated with other atoms or molecules. Thus, it is unique in behaviors and is therefore best placed separately in the periodic table. Hydrogen occupies a unique position in modern periodic table.

Key Concept: Why does knowing an atom’s atomic number allow you to determine its number of electrons? Can you determine how many neutrons an atom has by its atomic number? Why or why not? 

Well, if the atom is neutral, that is, it has the same number of protons as it does electrons, by knowing the atomic number, we are able to know the number of electrons. Also, by knowing the atomic number, and effectively, knowing it’s electron configuration, we can figure out what ions it can make (Ion charges)

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You can simply subtract the atomic number from the mass number to find the number of neutrons. If the atom is neutral, the number of electrons will be equal to the number of protons.

Module 2.2: Matter Combined: Mixtures and Chemical Bonds Now we look at what happens when we combine two or more atoms and the ways in which we can combine them. When you finish this module, you should be able to do the following: 1. Describe the three different types of mixtures and explain the difference between a solvent and a solute. Mixtures can be classified on the basis of particle size into three different types: solutions, suspensions, and colloids. A solute is a substance in which is dissolved in another substance, the solvent.

2. Explain how the number of electrons in an atom’s valence shell determines its stability and ability to form chemical bonds. The number of electrons in the outermost shell of a particular atom determines its reactivity, or tendency to form chemical bonds with other atoms. Some atoms can be stable with an octet even though their valence shell is the 3n shell, which can hold up to 18 electrons. 3. Distinguish between the terms molecule, compound, and ion. 

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An atom is a singular nucleus (protons and usually neutrons except for hydrogen-1 which only has a proton) surrounded by at least one electron. No. of electrons = no. of protons, so it has no charge. A molecule is a group of two or more atoms covalently bonded together into one structure, like water ( H2O ), glucose ( C6H12O6 ) and nitrogen gas ( N2 ). They don’t have to be different elements. A compound is a combination of two or more different atoms. Most molecules are compounds, but not all compounds are molecules. A compound can be a molecule held by covalent bonds, an ionic compound held together by ionic bonds (e.g. sodium chloride a.k.a table salt) or a metallic compound held by metallic bonds (e.g. gold, iron, magnesium etc.). An ion is just an atom that has gained or lost electrons, and therefore gained a negative or positive charge respectively. Oppositely charged ions attract each other and form ionic compounds.

4. Explain how ionic, nonpolar covalent, and polar covalent bonds form, and discuss their key differences. 

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The formation of an ionic bond is the result of the transfer of one or more electrons from a metal onto a non-metal. Polar bonding is the unequal sharing of electrons between two different non-metal atoms. Nonpolar covalent bonds, with equal sharing of the bond electrons, arise when the electronegativities of the two atoms are equal. If the difference in electronegativity is greater than 2, then it is ionic. A covalent bond is the sharing of electrons, nonpolar is equal sharing and polar is unequal sharing. If it is less than 1.5, then it is covalent.

5. Describe how hydrogen bonds form and how they give water the property of surface tension. 

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hydrogen bond is the electromagnetic attraction created between a partially positively charged hydrogen atom attached to a highly electronegative atom and another nearby electronegative atom. The property of water's surface tension is explained by the ability of water molecules to form hydrogen bonds. ... Hydrogen bonds hold the water molecules in place in the solid phase therefore they are closer together making it more dense.

Build Your Own Glossary Use the glossary at the back of your book or look through the module to define the following terms. Key Terms for Module 2.2 Term

Definition

Mixture

is defined as the result of combining two or more substances, such that each maintains its chemical identity.

Molecule

A molecule is two or more atoms bonded together to form a single chemical entity.

Suspension

The state in which the particles of a substance are dispersed but not totally dissolved in a fluid

Colloid

A dispersion of a high-molecular-mass solute in a liquid phase.

Solution

a mixture in which molecules of one substance are distributed evenly in another.

Chemical bond

a bond that holds atoms together.

Valence electron

to any of the electrons on the outer shell of the nucleus of an atom.

Ionic bond

also called electrovalent bond, type of linkage formed from the electrostatic attraction between oppositely charged ions in a chemical compound.

Ion

any atom or group of atoms that bears one or more positive or negative electrical charges. Positively charged ions are called cations; negatively charged ions, anions.

Nonpolar covalent bond

type of bond that occurs when two atoms share a pair of electrons with each other.

Polar covalent bond

type of covalent bond between two atoms in which electrons are shared unequally.

Hydrogen bond

an electrostatic attraction between a hydrogen atom in one polar molecule (as of water) and a small electronegative atom (as of oxygen, nitrogen, or fluorine) in usually another molecule of the same or a different polar substance

Key Concept: What is the key difference between the components of a mixture and the components of a chemical bond? 

Compounds are substances which can be formed by chemically combining two or more elements. Mixtures are substances that are formed by physically mixing two or more substances.

Key Concept: Which electrons are important to consider in chemical bonding? Why are these electrons so important? 

the outer most shell of an atom are called valence electrons. They are important because they determine how an atom will react.

Key Concept: What is the fundamental difference between an ionic and a covalent bond? 

covalent bonds, atoms share electrons, whereas in ionic bonds atoms transfer electrons.

Key Concept: How do hydrogen bonds differ from polar covalent bonds?

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A hydrogen differs from a covalent bond because it's an attraction, not a real bond. It's an attraction because the positive charge of the hydrogen is attracted to a negative charge of another atom.

Module 2.3: Chemical Reactions The number of chemical reactions that occur in the human body each second is staggering, totaling in the hundreds of trillions to quadrillions. This module introduces you to how chemical reactions occur and the many different factors that regulate them. When you complete this module, you should be able to do the following: 1. Explain what happens during a chemical reaction.  Chemical reactions involve breaking chemical bonds between reactant molecules (particles) and forming new bonds between atoms in product particles (molecules). 2. Describe the forms and types of energy and apply the principles of energy to chemical bonds and endergonic and exergonic reactions. Potential energy is stored energy and the energy of position. Kinetic energy is the motion of waves, electrons, atoms, molecules, substances, and objects. Chemical energy is energy stored in the bonds of atoms and molecules Thermal energy, or heat, is the energy that comes from the movement of atoms and molecules in a substance.  Radiant energy is electromagnetic energy that travels in transverse waves 3. Describe and explain the differences between the three types of chemical reactions.    

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Combination/Synthesis reaction: In this reaction, two simple reactants react to form one product.Such reactions may be represented by equations of the following form: X + Y → XY. Displacement reaction: In this reaction(mostly an ionic reaction), a more reactive element displaces a less reactive element form it's salt.Such reactions may be represented by equations of the following form: XY → X + Y. Decomposition reaction: Exact opposite of Combination reaction. A compound dissociates into elements and/or simpler compounds.Such reactions may be represented by equations of the following form: Z + XY → X + ZY. Double displacement reaction: Think a displacement reaction, except replace the 'reactive element' with another. Basically from the two compounds the two cations(or two anions, if you want to imagine like that) switch places.Such reactions may be represented by equations of the following form: AB + XY → XB + AY.

4. Describe the factors that influence reaction rates.     

surface area of a solid reactant. concentration or pressure of a reactant. temperature. nature of the reactants. presence/absence of a catalyst.

5. Explain the properties, actions, and importance of enzymes. 

Enzymes are biological molecules (typically proteins) that significantly speed up the rate of virtually all of the chemical reactions that take place within cells. They are vital for

life and serve a wide range of important functions in the body, such as aiding in digestion and metabolism.

Build Your Own Glossary Use the glossary at the back of your book or look through the module to define the following terms. Key Terms of Module 2.3 Term

Definition

Chemical reaction

a process that involves rearrangement of the molecular or ionic structure of a substance, as opposed to a change in physical form or a nuclear reaction.

Reactant

a substance that takes part in and undergoes change during a reaction.

Product

he substances made by a chemical reaction. bond energy. the amount of energy that will break a bond between two atoms. equilibrium.

Potential energy

Potential energy is stored energy and the energy of position.

Kinetic energy

energy in motion

Endergonic reaction

Endergonic reactions absorb energy from their surroundings.

Exergonic reaction

Exergonic reactions release energy to the surroundings.

Catabolic reaction

large molecules are broken down into smaller ones.

Exchange reaction

involving transfer of electrons from one chemical to another

Anabolic reaction

the joining of smaller molecules into larger ones

Activation energy

minimum amount of energy that must be provided for compounds to result in a chemical reaction.

Enzyme

a substance produced by a living organism which acts as a catalyst to bring about a specific biochemical reaction.

Complete It: Energy and the Cell Fill in the blanks to complete the following paragraph that describes the types of energy and how it applies to the cell.

Energy is defined as the capacity to do work or to produce heat. Energy that is ready to be released is called Potential Energy, whereas energy in motion is called Kinetic Energy. Chemical energy is the energy inherent in Chemical Bonds. The energy generated by the movement of charged particles is called electrical energy. Energy transferred from one body to another is known as an Thermal Energy.

Key Concept: You are in a lab trying to carry out a reaction. You find that if you do nothing, the reaction does not proceed. But if you add heat, the reaction proceeds to completion. Is this reaction endergonic or exergonic? Why? 

endergonic reaction, energy is absorbed from the surroundings.

Identify It: Chemical Reactions Identify each of the following types of reactions:

MgCl2 + 2LiI 

MgI2 + 2LiCl Double Displacement (Metathesis)

C6H12O6 + C6H12O6 

C12H22O11 + H2O

condensation reaction Na+ + OH−

NaOH 

double replacement reaction.

Key Concept: How important are enzymes to our biology? Explain.

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Enzymes create chemical reactions in the body. They actually speed up the rate of a chemical reaction to help support life.

Module 2.4: Inorganic Compounds: Water, Acids, Bases, and Salts Module 2.4 in your text explores biochemistry, teaching you about the basic properties and physiological importance of many different inorganic compounds. At the end of this module, you should be able to do the following: 1. Discuss the physiologically important properties of water. 

polarity, cohesion, adhesion, surface tension, high specific heat, and evaporative cooling.

2. Explain why certain molecules and compounds are hydrophilic and why others are hydrophobic.  Hydrophilic molecules are those that are polar (i.e. - charged, ionized, partially charged) in nature, like water, meaning their atoms mix and/or interact with water.  Hydrophobic molecules are non-polar molecules (no net charge, no unpaired electrons), such as oils, that do not mix with water and will thus create two layers. 3. Describe the properties of acids and bases with respect to hydrogen ions.  An acid is any hydrogen-containing substance that is capable of donating a proton (hydrogen ion) to another substance. A base is a molecule or ion able to accept a hydrogen ion from an acid. 4. Explain what the pH scale represents, and why a given value is acidic, neutral, or basic. 

pH is a measure of how acidic/basic water is. The range goes from 0 - 14, with 7 being neutral. pHs of less than 7 indicate acidity, whereas a pH of greater than 7 indicates a base.

5. Explain the function of a buffer. 

The main purpose of a buffer solution is just to resist the change in pH so that the pH of the solution won't be much affected when we add an acid or base into it.

6. Define the terms salt and electrolyte and give examples of physiological significance. 

Electrolytes are minerals in your body that have an electric charge.

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A salt consists of the positive ion (cation) of a base and the negative ion (anion) of an acid

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An example of physiological is a person shedding...