ENVIRON 102 Chapter Notes - Chapter 3: Transform Fault, Ionic Bonding, Keratin

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Chapter 3: The Physical Science of the Environment

3.1 Chemistry of the Environment

 All matter is made up of 1 or more elements

o Element – a chemical that cannot be broken down into other chemicals

 Physical and chemical properties of elements are determined by their atoms

 Two or more atoms = molecules

 Protons, neutrons, and electrons have mass that is responsible for the gravitational attraction of

all matter to other matter

 Isotopes: atoms with varying number of neutrons

o Similar chemical qualities, but different mass

o Some isotopes have nuclei that are unstable and can break apart = radioactive =

radioisotope

▪ Radioactive – can spontaneously decay

▪ Emits high-energy protons, neutrons, and electrons, and radiation

▪ Decay turns radioactive isotopes into lighter isotopes that can either be stable or

radioactive

▪ Rate of decay – half-life – length of time it takes for half of the radioisotope to decay

 Compounds: molecules made with more than one element

 Bonds (measured by energy to break it) hold atoms together

o Covalent bond: atoms share electrons

▪ Ex: O2 – electrical charge is shared equally – nonpolar

▪ Ex: H20 – oxygen atom attracts electrons more than the hydrogen atoms

▪ Oxygen side becomes slightly negative and hydrogen side becomes slightly positive

charge

o Ionic bond: one atom donating the electron to another atom

▪ Receiving atom will be negatively charged and giving atom will be positively

charged

▪ Electrically charged atoms are called ions

▪ Ionic bonds form ionic compounds or salts, not molecules

o Dipole bond: weaker bonds formed between atoms and molecules as a consequence of

shifts in electrical charge

▪ Strength depends on extent of polarity (difference between charges)

▪ Affect the chemical and physical properties of polar molecules

▪ Ex: geckos are able to climb walls because of dipole bonds between the toe

molecules and the wall molecules

 Water molecules are polar so they form dipole bonds with other water molecules

o Dipole bonds involve hydrogen atoms – aka hydrogen bonds

o Responsible for cohesive nature

o Heat causes hydrogen bonds to weaken

▪ 100 degrees Celsius  all bonds are broken

o Coldness causes hydrogen bonds to form

▪ Water becomes denser; densest at 4 degrees Celsius

▪ Below 4 degrees Celsius, water becomes a lattice structure and becomes less dense

 Polarity  water is a great solvent

o Solvent – substance that other chemicals are able to dissolve in

o Ex: ionic compounds (NaCl) are soluble in water while nonpolar (oils) are not

 Water can dissociate (break apart) into hydrogen ions (H+) and hydroxyl ions (OH-)

o Pure water has equal amounts of hydrogen and hydroxyl ions

 pH scale: quantitative representation of the relative amounts of hydrogen ions and hydroxyl ions

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o Acidic – more H+

o Basic – more OH-

o Each pH unit reflects a 10 fold change in H+ levels

▪ Ex: Compared to a neutral solution, a solution with pH 6 has 10 times more H+, and a

solution with pH 5 has 100 times more H+

3.2 The Organic Chemistry of Life

 Organic molecules: carbon atoms covalently bonded to hydrogen and other atoms

 Inorganic compounds: not made up of carbon and hydrogen

 Hydrocarbons: made up of carbon and hydrogen

o Methane (CH4) – simplest hydrocarbon

 Carbohydrates: made up of carbon, hydrogen, and oxygen

o Sugars: general chemical formula (CH2O)n, n is between 3 and 7

▪ Glucose (C6H12O6) is the basic source of energy for most organisms and an

ingredient for synthesis of other organic molecules

▪ Table sugar: Glucose + Fructose

 Lipids (fats and oils): long chains of carbon and hydrogen (nonpolar), short region of oxygen

(polar)

o Nonpolar region is reason for insolubility in water

o Constituent of membranes

o Forms of energy storage

 Macromolecules formed by small organic molecules linked together

 Polymers formed by simple organic molecules (carbohydrates or hydrocarbons)

 Polysaccharides: polymers of simple sugars

o Starch and cellulose are polysaccharides made of up glucose molecules

o Difference has to do with the bonds between glucose molecules – cellulose has more

resistant bonds

 Proteins are polymers made of amino acids (nitrogen-containing organic molecules)

o 20 amino acids – contain an amino group (-NH2) and a carboxylic acid group (-COOH)

o Unique 3D shapes, sequences of amino acids, chemical interactions and bonds  proteins’

functions

▪ Ex: keratin (found in fingernails and hair) provides structure

▪ Ex: enzymes are catalysts for chemical reactions

 Nucleic acids are polymers of nucleotides

o Nucleotide – 5-carbon sugar, a phosphate group (-PO4), and a nitrogenous base

o DNA is hereditary material

▪ Nucleotides in DNA contain sugar deoxyribose and a nitrogenous base (GCAT)

▪ Double helix ladder structure; ladder formed with deoxyribose and phosphate

groups; rungs formed by paired nitrogenous bases

▪ Genes: segments of DNA that provide the code for synthesizing proteins

▪ Genome: complete set of DNA of an organism

o RNA – single strand, U instead of T, sugar ribose instead of sugar deoxyribose

▪ Uses information coded in DNA

o Protein synthesis – two-step process of transcription and translation

▪ Transcription: DNA code is rewritten as RNA

▪ Translation: RNA serves as blueprint for the assembly of protein

3.3 Energy and the Environment

 Energy: capacity to do work

 First law of motion: any object at rest will stay at rest and any object in motion will stay in motion

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Document Summary

Chapter 3: the physical science of the environment. All matter is made up of 1 or more elements: element a chemical that cannot be broken down into other chemicals. Physical and chemical properties of elements are determined by their atoms. Protons, neutrons, and electrons have mass that is responsible for the gravitational attraction of all matter to other matter. Compounds: molecules made with more than one element. Polarity water is a great solvent: solvent substance that other chemicals are able to dissolve in, ex: ionic compounds (nacl) are soluble in water while nonpolar (oils) are not. Water can dissociate (break apart) into hydrogen ions (h+) and hydroxyl ions (oh-: pure water has equal amounts of hydrogen and hydroxyl ions. Organic molecules: carbon atoms covalently bonded to hydrogen and other atoms. Hydrocarbons: made up of carbon and hydrogen. Inorganic compounds: not made up of carbon and hydrogen: methane (ch4) simplest hydrocarbon.

Related Questions

Predict the charge that an aluminum ion would have.

Terms in this set (26)

example of the law of multiple proportions

Two different compounds formed from carbon and oxygen have the following mass ratios:

1.33 g O: 1 g C and 2.66 g O: 1 g C.

2) Which of the following statements is FALSE according to Dalton's Atomic Theory?

A) Atoms combine in simple whole number ratios to form compounds.

B) All atoms of chlorine have identical properties that distinguish them from other elements.

C) One carbon atom will combine with one oxygen atom to form a molecule of carbon monoxide.

D) Atoms of sodium do not change into another element during chemical reaction with chlorine.

E) An atom of nitrogen can be broken down into smaller particles that will still have the unique properties of nitrogen.

The mass number is equal to

the sum of the number of protons and neutrons

a subatomic particle is

A neutral atom contains the same number of protons and electrons

true statement about isotopes

Some elements have 3 or more naturally occurring isotopes

Identify a cation

An atom that has lost an electron

What species is represented by the following information?

p+ = 12 n° = 14 e- = 10

Mg2+

What species is represented by the following information?

p+ = 47 n° = 62 e- = 46

Ag+

What species is represented by the following information?

p+ = 17 n° = 18 e- = 18

Cl-

Predict the charge that an aluminum ion would have

Predict the charge that a calcium ion would have

Predict the charge that an ion formed from sulfur would have

Predic

tangnu832

A nuclear reaction is represented by an equation similar to theequation for a chemical reaction. An example of a nuclear reactionis the decay of radium into radon by the emission of an alphaparticle (a helium nucleus). The equation for this reactionis

^{226}_{\ 88}{\rm Ra}\; \rightarrow \, ^{222}_{\ 86}{\rmRn}+\;^4_2{\rm He}.

The superscript preceding each element indicates the nucleon numberof that particular nucleus (total number of protons and neutrons).The subscript indicates the charge of the nucleus, which is equalto the atomic number for nuclei. Nuclear reactions frequentlyinvolve electrons (sometimes called beta rays) and photons(sometimes called gamma rays). Electrons, which have nucleon number0 and charge -1, are represented in equations as either ^{\ \;0}_{-1}\beta or ^{\ \; 0}_{-1}{\rm e}. Photons are represented as^{0}_{0}\gamma to emphasize that they have no nucleon number andcarry no charge.

In nuclear reactions, several conservation laws are usuallysufficient to determine the products or reactants. One of these isconservation of nucleon number. The total number of neutrons andprotons in all of the reactants must be the same as the totalnumber of protons and neutrons in the products. Although protonsand neutrons sometimes change into one another, neither can simplydisappear. Another important conservation law is conservation ofcharge. The net charge of the reactants must be the same as that ofthe products.

Notice that, in our equation for the decay of radium, the sum ofthe nucleon numbers on each side is 226 and the sum of the chargeson each side is 88. If you knew everything in this equation exceptthe isotope of radon produced, you could simply subtract 4 from 226to find the nucleon number required to make the nucleon number ofthe products equal the nucleon number of the reactants. Similarly,if you knew everything in this equation except for the identity ofthe product element, you could simply subtract 2 from 88 and thenlook in a periodic table to find that the element with atomicnumber 86 is radon.

In parts A and B consider the decay of radon by alpha particleemission:

^{222}_{\ 86}{\rm Rn}\;\rightarrow\;X +\,^{4}_{2}{\rm He}.

a. What is the nucleon number of the element X?
Express your answer as an integer.

b. What is the atomic number (nuclear charge) of the elementX?
Express your answer as an integer.

n parts C and D consider the decay of Potassium-43 into calcium-43via the following reaction:

^{43}_{19}{\rm K} \rightarrow ^{43}_{20}{\rm Ca}+\,X.

c. What is the charge of the emitted particle X?
d. is not visible yet

E. An isotope of potassium with a half-life of roughly one billionyears is often used in radioactive dating. This isotope decaysthrough electron capture, the process of drawing an electron intothe nucleus. What is the chemical symbol for the element thatresults from this process? The equation for the reaction is

^{40}_{19}{\rm K}+\,^{\ \;0}_{-1}{\rm e}\rightarrow \,?.
Express your answer as a chemical symbol (e.g., Na forsodium).

f. The reaction energy of a reaction is the amount of energyreleased by the reaction. It is found by determining the differencein mass between the reactants and products and then using E=mc^2 toconvert the lost mass into the released energy.

Look again at the equation for the decay of radium (Ra), given inthe introduction. Use the following table of masses to determinethe reaction energy of this reaction.
Nucleus or particle Mass in atomic mass units
radium-226 226.025402
radon-222 222.017571
alpha particle 4.002602
Express your answer in joules to three significant figures.

please answer fully... thank you

1. (1 point) What might be damaged by ionizing radiation? * paper soft tissue wood lead

2. (1 point) When an atom emits an beta particle, what is the change in the atomic number? * no change decrease by 1 decrease by 2 increase by 1 increase by 2

3. (1 point) What is the change in atomic mass caused by the emission of gamma radiation? * no change decrease by 1 decrease by 2 increase by 1 increase by 2

4. (1 point) Which of the following materials would effectively stop gamma radiation? * one foot of concrete single sheet of paper thin pieces of wood three inches of lead

5. (1 point) When the ratio of neutron-to-proton dictates that a neutron must break down it will form _________. * A helium nucleus An alpha particle A proton and an electron Two protons

6. (1 point) What determines the type of decay if a nucleus falls outside the band of stability? * the ratio of alpha particles to beta particles the ratio of beta particles to alpha particles the ratio of neutrons to protons the ratio of protons to neutrons

7. (1 point) A positron is emitted when ____________. * an alpha particle forms a beta particle forms proton converts to a neutron neutron converts to a proton

8. (1 point) How does an atom with too few neutrons relative to protons undergo radioactive decay? * by converting proton to a neutron by converting a neutron to a proton by emitting an alpha particle by emitting a beta particle

9. (1 point) How much of the original sample would remain after two half lives have past? * There would be nothing of the original left There would be half of the original sample still there There would be one quarter of the sample still present There would only be one eighth of the original sample still present

10. (1 point) What is the approximate half life of carbon- 14? * hundreds of years thousands of years million of years billion of years

11. (1 point) A reaction where a heavier nucleus splits into smaller nuclei is called ___________. * a chemical reaction background radiation fission fusion

12. (1 point) __________ and ___________ are used as moderators to capture neutrons in a nuclear reactor. * Cadmium and other metal Carbon and water Liquid sodium and water Plutonium and neptunium

13. (1 point) For a person working in a place where they might be exposed to radiation a _________ is routinely used to check their exposure. * film badge Geiger counter moderating rod scintillation counter

14. (1 point) Radioisotopes are used to do all of the following except __________. * analyze matter. diagnose medical problems. improve the flavor of food. treat diseases. study plant growth. Open response questions: Answer the following with complete sentences or if math is involve show the work

15. (3 point) The radioisotope radon-222 has a half-life of 3.8 days. How much of a 198.6 g sample of radon -222 would be left after approximately 23 days? ( Show your work) * Your answer

16. (3 point) How can an element be artificially transmuted? Give an example that has an element and what it is transmuted into. * Your answer

17. (4 point) Why does the mass and charge of an alpha particle make it less penetrating than a beta or gamma? Discuss both the mass and the charge(2 points each). *

ENVIRON 102 Chapter Notes - Chapter 3: Transform Fault, Ionic Bonding, Keratin

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