Q1 ch 2 mastering bio lab
The brackets are indicating a(n) _____ bond.
hydrogen A hydrogen atom with a net positive charge is attracted to an oxygen atom with a net negative charge.
Chapter 2-03-Activity: Acids, Bases, and pH c*In a neutral solution the concentration of _____.
hydrogen ions is equal to the concentration of hydroxide ions *This is the definition of a neutral solution.
In salt, what is the nature of the bond between sodium and chlorine?
ionic -Sodium and chlorine ions are attracted to each other.
Chapter 2-03. Chemistry Review - Acids, Bases, & pH: Buffers d*How does the way a buffer stabilizes pH during addition of acid differ from the way the same buffer stabilizes pH during addition of base?
it's the same reaction running backward or forward *The buffer accepts H+ in one case; it gives off H+ in the other case.
Chapter 2-03.GraphIt!: Ocean Acidification b)How could this data be best represented graphically?
line graph *Line graphs are appropriate when both the x and y axes represent continuous numerical data that will be connected by a line, like these time-series data.
An acid
releases H+ in a solution
What type of bond joins the carbon atom to each of the hydrogen atoms?
single (nonpolar) covalent -Each carbon-hydrogen bond involves a single pair of equally shared electrons.
In addition to the risk of accidents, which of the following is a problem when nuclear power is used as a method of generating electrical power?
storage and disposal of spent fuel rods
Which of the following are trace elements required by your body for proper health?
zinc, tin, molybdenum
What stops some insects from drowning on top of water?
B) Surface tension.
Which of these figures correctly illustrates the nature of the bonding of H2O?
Oxygen is more electronegative than hydrogen.
Chapter 2-03. Chemistry Review - Acids, Bases, & pH: Buffers b*A buffer consists of undissociated acid (HA) and the ion made by dissociating the acid (A-). How does this system buffer a solution against decreases in pH?
(b) A- reacts with H+ to become HA. *A- binds most of the added H+, so not much H+ is left to lower the pH.
Chapter 2-03. Chemistry Review - Acids, Bases, & pH: Buffers f*To make a buffer, you need to ...
(d) have a weak acid or a weak base half ionized in water. *When half of the molecules are ionized, there are plenty of molecules that can either absorb H+ or give off H+ when the pH is disturbed from outside.
Chapter 2-03.GraphIt!: Ocean Acidification c)The following graphs represent the future projections from Part B. Drag the labels to their appropriate locations on the graphs.
*Atmospheric C02 (PPM) *(Oceanic pH) Y-axis *Year X-Axis *optimistic *middle ground *pessimistic
Earth's giant water supply—the oceans, seas, lakes, and rivers—enabled the origin and evolution of life. How can water enable life?
+ All of the listed responses are correct. -Water can dissolve an enormous variety of substances necessary for life. -It keeps air temperatures within limits that permit life. -Cohesion of water molecules is important for transport of water from the roots to leaves of trees. -The stability of ocean temperatures creates a favorable environment for marine life.
Which of the following is a false statement about water?
+ Ice is more dense than liquid water. -Water moderates temperature. -Water has high cohesion.
Which of the following is a true statement about ionic bonds?
-Ionic bonds result in ions in which a normally neutral atom becomes charged. -Sodium and chloride, which together form table -salt, are held together by ionic bonds. + All of the listed answers are correct. In ionic bonds, atoms are held together by the transfer of electrons.
Learning through Art: The pH Values of Solutions *Refer to the pH scale below as you complete this activity about pH
-The term for a solution with a low pH number, such as lemon juice or vinegar, is acidic. - The term for a solution that has an equal concentration of H+ and OH- is neutral. -The term for a solution with a high pH number, such as ammonia or bleach, is basic. - An acid is a compound that donates H+ to a solution. -The higher the pH number, the higher the concentration of OH- in a solution. -A substance that accepts H+ when they are in excess and donates H+ when their concentration drops is called a buffer
Chapter 2-03. Interpreting Data: Radiometric Dating b**French scientists used carbon-14 dating to determine the age of prehistoric wall paintings in the Niaux caves . They determined that the paintings were made using natural dyes approximately 13 thousand years ago. *Use your knowledge of carbon-14 dating to determine which two statements are true. (Remember that the half-life of carbon-14 is 5.7 thousand years.)
1.Cave paintings that are 7.3 thousand years old would contain twice as much carbon-14 as the Niaux cave paintings. 2.In another 5.7 thousand years, the Niaux cave paintings will contain half as much carbon-14 as they currently do.
Chapter 2-03.GraphIt!: Ocean Acidification d)The graphs from Part C are shown here. Can you interpret them?Drag the terms on the left to the appropriate blanks on the right to complete the sentences.
1. In 2016, atmospheric CO2 was at 400 ppm, and oceanic pH was at 8.1. 2. Under the Optimistic scenario, CO2 concentrations in the atmosphere will increase but will remain under 600 ppm through 2090. 3. Under the Middle Ground scenario, CO2 concentrations in the atmosphere will get close to, but are not projected to exceed 700 ppm by 2090. 4. Under the Pessimistic scenario, CO2 concentrations in the atmosphere are projected to exceed 800 ppm by 2090. 5. Across all three scenarios, ocean pH falls below 8.0 by 2090. 6. From the information in the graphs, you can conclude that oceanic pH and atmospheric CO2 concentration are negatively (or inversely) correlated. 7. Although not reflected in this graph, you can infer that as atmospheric carbon dioxide increases, oceanic carbon dioxide concentrations also increase, suggesting that the two variables are positively (or directly) correlated.
A chemical bond is a strong attraction between two or more atoms. Can you identify the properties of different types of chemical bonds? 1)-. A(n) --IONIC--bond forms when one atom gives up one or more electrons to another atom. 2. Atoms or molecules with a net electric charge due to the loss or gain of one or more electrons are . 3. A(n) bond involves the sharing of electron pairs between atoms, also known as a molecular bond. 4. When one pair of electrons is shared between two atoms, a bond is formed. 5. When two pairs of electrons are shared between two atoms, a bond is formed. 6. A bond is a type of chemical bond where a pair of electrons is unequally shared between two atoms. As a result, one end of the molecule has a slightly negative charge and the other a slightly positive charge. 7. Atoms involved in a bond equally share electrons; there is no charge separation to the molecule. 8. A weak bond called a bond results from an attraction between a slightly positive region in a molecule and a slightly negative region in the same or a different molecule.
1. ionic 2. ions 3. covalent 4.single 5.double 6.polar 7.nonpolar 8.hydrogen -In chemical reactions, atoms gain, release, or share electrons. There are two main ways that atoms can bond together to form molecules: by sharing electrons, or by transferring electrons and creating two oppositely charged atoms Covalent bonds involve the sharing of one or more electrons between atoms. Ionic bonds involve the transfer of one or more electrons from one atom to another.
Chapter 2-03.Identifying Major Themes - Chapter 2 *Can you identify the major theme illustrated by each of the following examples? If necessary, you may review the themes in Chapter 1 of your book. Match the themes on the left with the examples on the right. Each theme may be used once, twice, or not at all.
1.Life on Earth began in water 3 billion years before spreading onto land. Evolution 2.Two molecules of hydrogen peroxide react to produce two molecules of water and one molecule of oxygen. 3.The number of electrons in an atom determines the chemical properties of that atom. Information flow 4.Earth's giant water supply stores a huge amount of heat from the sun during warm periods and gives off heat that warms the air during cold periods. This enables temperatures on the planet to stay within the limits that permit life. and
Chapter 2-03. Interpreting Data: Radiometric Dating a*After 17.1 thousand years, what percentage of the original carbon-14 would be left in an organism's remains?
12.5%
This atom can form up to _____ single covalent bond(s).
4 -There are four electrons in the outermost electron shell.
An uncharged atom of boron has an atomic number of 5 and an atomic mass of 11. How many protons does boron have?
5 -The atomic number is equal to the number of protons.
What is the atomic number of an atom that has 6 protons, 6 neutrons, and 6 electrons?
6
What is the atomic number of an atom that has 6 protons, 6 neutrons, and 6 electrons?
6 -This is an atom of carbon, an element with 6 protons. Atomic number is the number of protons in an atom.
What name is given to the bond between water molecules?
A hydrogen atom with a net positive charge is attracted to an oxygen atom with a net negative charge.
Can you label the atoms, partial charges, and types of bonds associated with these water molecules? -Drag the labels to their appropriate locations in this diagram. First use pink labels to identify the atoms and charges. Then use blue labels to identify the bonds. Labels can be used once, more than once, or not at all.
A. H; B. O; C. H; D. (+); E. (-); G. Polar covalent bond; F. Hydrogen bond.
Drag the vocabulary terms onto this concept map about the components of an atom.
A. Protons; B. Neutrons; C. Electrons; D. +1; E. Nucleus; F. -1; G. Atomic number; H. Mass number.
Chapter 2-03. Chemistry Review - Acids, Bases, & pH: Buffers e*Which answer helps to explain why all living cells need pH buffers?
Amino acid side chains have many carboxyl and amino groups. *When these side chains ionize, they exert forces that affect the protein's folding. Thus, if pH isn't stabilized, the proteins will change their folding and may not function properly.
Each water molecule is joined to _____ other water molecules by ____ bonds.
As can be seen in the illustration on page 1 of the activity titled "The Polarity of Water" a water molecule is joined to four other water molecules by hydrogen bonds.
Fluorine's atomic number is 9 and its atomic mass is 19. How many neutrons does fluorine have?
Atomic mass is equal to the number of protons plus the number of neutrons (19-9 = 10).
Which of these refers to atoms with the same atomic number but different atomic masses?
Atoms with the same atomic number and different atomic masses are referred to as isotopes.
Which of these is weakest? A) Covalent bonds B) Ionic bonds C) Hydrogen Bonds
C) Hydrogen Bonds -Hydrogen Bonds are weaker than covalent bonds because they do not involvesharing of electrons, and they are weaker than ionic bonds because they involvethe attraction of partial (not full) opposite charges.
After oxygen, carbon, hydrogen, and nitrogen, which element occurs in the greatest quantity in your body?
Calcium is an important component of your bones and teeth, and it makes up about 1.5% of your total body weight.
Imagine a row of pills. Each pill contains the recommended daily allowance of one mineral. Of the following minerals, which do you suppose would come in the biggest pill?
Calcium makes up about 1.5% of your body weight, more than any other mineral. Therefore, it would come in the biggest pill.
We may never know how many people became ill or died as a result of the Chernobyl accident. What is the main reason why this is so difficult to determine?
Cancer might not occur for many years after exposure to ionizing radiation.
The atomic number of carbon is 6. What does this mean?
Carbon has 6 protons
Water is sometimes called the "universal solvent." Is that accurate?
For the most part. Water readily dissolves most substances, but not hydrophobic ones.
Chapter 2-03-Activity: Acids, Bases, and pH b*What is the arrow pointing to?
Hydroxide ion (OH-)
Why is ionizing radiation damaging to cells?
It knocks the electrons from the cell's molecules, forming ions and breaking bonds.
The concrete sarcophagus enclosing the damaged reactor is crumbling, allowing radiation to leak out into the environment. An animation of a new protective cover is shown in the video. Why hasn't the construction of this cover been completed?
It will be extremely expensive to build.
*Chapter 2-03 *Identifying Major Themes - Chapter 2 Part A Part complete Can you identify the major theme illustrated by each of the following examples? If necessary, you may review the themes in Chapter 1 of your book. Match the themes on the left with the examples on the right. Each theme may be used once, twice, or not at all. ResetHelp Pathways that transform energy and matter Evolution Information flow Relationship of structure to function Interactions within biological systems
Life on Earth began in water 3 billion years before spreading onto land. Evolution Two molecules of hydrogen peroxide react to produce two molecules of water and one molecule of oxygen. Pathways that transform energy and matter The number of electrons in an atom determines the chemical properties of that atom. Relationship of structure to function Earth's giant water supply stores a huge amount of heat from the sun during warm periods and gives off heat that warms the air during cold periods. This enables temperatures on the planet to stay within the limits that permit life. Pathways that transform energy and matter and Interactions within biological systems
Which statement best describes why a water molecule is polar?
Oxygen exerts a stronger pull on the shared electrons than the hydrogens do. -This unequal sharing of electrons is critical to understanding many properties of water.
Chapter 2-03.GraphIt!: Ocean Acidification e)Part E) As explained in the GraphIt! activity, the way ocean acidification works is that atmospheric carbon. . . forming more bicarbonate ions. Drag "True" or "False" to the end of each statement.
TRUE: Although not reflected in the graph, based on how ocean acidification works...can be predicted to be positively (or directly) correlated.TRUE: Coral reef calcification rates are projected to steadily decline as atmospheric CO2 concentrations increase.TRUE: As atmospheric CO2 concentrations reach 560 ppm... preindustrial level.FALSE: As atmospheric CO2 concentrations reach 840 ppm, or three times the preindustrial level, the calcification rate will be reduced to 30 mmol/m2/day.FALSE: The data in this graph could also be plotted as a pie chart.FALSE: Declining coral calcification rates suggests a decrease in the level of bicarbonates and an increase in the level of carbonates in seawater.
Chapter 2-03-Activity: Acids, Bases, and pH a*What is the arrow pointing to?
The arrow is indicating a single proton, a hydrogen ion (H+).
How does the cohesion of water relate to the themes of biology?
The cohesion of water is due to the relationship between its structure and function. The molecular structure of water influences how it functions by allowing hydrogen bonds to form and creating a high cohesion.
What process exerts the pull on water molecules that is relayed from leaf to root via cohesion?
The evaporation of water from leaves moves water up from the roots via cohesion.
Although the forest is growing quickly around Chernobyl, and some of the wildlife is thriving, studies show that biodiversity around Chernobyl has been reduced by over 50% since the accident. Why?
The ionizing radiation affects the DNA of the wildlife, just as it affects the DNA of humans.
Which best describes how charges are distributed on a water molecule?
The oxygen end is negative relative to the end with the two hydrogen atoms.
Connecting the Concepts: Water's Life-Supporting Properties *Can you complete this paragraph about the life-supporting properties of water?
The polarityof water molecules and the hydrogen bonds between water molecules explain most of water's life-supporting properties. The cohesionof water molecules to each other helps transport water from the roots to the leaves in plants. When water warms or cools, hydrogen bondseither break or form. Thus, water absorbs or releases a great deal of heat, helping to moderate temperatures. Because iceis less dense than liquid water, it floats and protects lakes andoceans from freezing solid. Water is a versatile solvent. Blood and other biological fluids are aqueous solutions with a diversity of dissolved solutes.
the tendency of an atom to pull electrons toward itself is referred to as its _____.
The question defines electronegativity.
Why is the town of Pripyat uninhabited?
The radiation levels in the town are still unsafe
Chapter 2-03-Activity: Acids, Bases, and pH d*How does the pH of the solution on the right compare with that of the solution on the left?
The solution on the right is basic relative to the solution on the left -The solution on the right has a lower concentration of hydrogen ions relative to hydroxide ions than does the solution on the left
You are making Kool-Aid. You mix the sugar and Kool-Aid into a pitcher of water. Which of the following is a true statement?
The sugar and Kool-Aid are the solutes, the water is the solvent, and the finished mixture is the solution.
You put some ice cubes in a glass and fill it to the brim with water. You forget about it for a while, then come back. What would you notice?
The water is at the same height or is slightly lower
Chapter 2-03. Chemistry Review - Acids, Bases, & pH: Buffers a*Which statement is true of pH buffers?
They consist of weak acids and weak bases. *By using weak acids and bases, the buffer can absorb or give off H+, stabilizing the pH.
Which statement correctly describes hydrogen bonds?
They hold together adjacent water molecules. -This attraction between adjacent water molecules is the cause of several important properties of water and ice.
Relative to other substances, water tends to resist changes in temperature. Why?
Water is highly cohesive. Its molecules tend to resist increases in their motion. When water is heated, some of the energy is used to disturb the hydrogen bonds between neighboring molecules
_________ forms _________ bonds and is _________.
Water; covalent; polar
Where do you find protons?
Within the nucleus
The figure shows how water forms hydrogen bonds. Drag the labels to their appropriate locations on the figure.
a) Water molecule b) hydrogen bond c)slightly positive d) slightly negative charge e) oxygen f) hydrogen
Chapter 2-03. Chemistry Review - Acids, Bases, & pH: Buffers c*Buffers work best when ...
about half of the buffer molecules are dissociated. *That arrangement results in the least change in pH when either acid or base is added.
Many of the first responders at the Chernobyl accident died within hours or days of working at the explosion site. What were they most likely to die from, and why?
acute radiation sickness due to exposure to ionizing radiation
Water readily sticks to many other substances, a property called ______.
adhesion
An ionic bond involves _____.
an attraction between ions of opposite charge
Atoms with the same number of protons but with different electrical charges _____.
are different ions
Bleach is a solution and has a high concentration of .
basic; OH-
There are four elements that together account for about 96% of your body weight. Which four are they?
carbon, hydrogen, nitrogen, oxygen. -Oxygen, carbon, hydrogen, and nitrogen are the four elements that together make up 96% of your body. The other 21 elements are required in much smaller amounts than these four. Oxygen accounts for nearly 2/3 of your body weight, making it the most abundant element in your body. Carbon is the 2nd most abundant element in your body; it is found in all organic molecules. Hydrogen is the 3rd most abundant element in your body, mostly in water. Nitrogen is the 4th most abundant element in your body.
Water striders are common insects that can skip across the surface of ponds and streams. This lifestyle is enabled by water's _____.
cohesion and resulting surface tension
What type of bond is joining the two hydrogen atoms?
covalent -A covalent bond is one in which electron pairs are shared.
Chapter 2-03.GraphIt!: Ocean Acidification a*The following graph shows the average pH of the ocean over the last 20 million years of Earth's history.
d) In the last 20 million years of Earth's history, the average pH has never gone below 8.0. B) Average ocean pH has fluctuated over the millennia from just over 8.0 to about 8.3.
A(n) _____ bond joins these two oxygen atoms.
double covalent -The oxygen atoms are sharing two pairs of electrons.
A(n) _____ refers to two or more atoms held together by covalent bonds.
molecule -A molecule is defined as two or more atoms held together by covalent bonds.
Which one element makes up the majority of your body weight?
oxygen -Your body is mostly water. And water is, by weight, mostly oxygen. (There are two hydrogen atoms for every oxygen atom in water, but one atom of oxygen has much more mass than one atom of hydrogen). That is why, if you weigh 150 pounds, about 100 of those pounds is oxygen.
The unequal sharing of electrons within a water molecule makes the water molecule _____.
polar -The electrons spend more time with the oxygen of the water molecule than with the hydrogens of water. Thus, the oxygen has a net negative charge and the hydrogens have a net positive charge.
In a water molecule, what type of bond is found between the oxygen and hydrogens?
polar covalent -While oxygen shares electrons with hydrogen, the electrons spend more time with the oxygen than with the hydrogens.