Science 12 Of EX?'s and Men
64.Classify each change as physical or chemical. Even if you are incorrect in your assessment, you should be able to defend why you chose as you did. Grape juice turns to wine. Wood burns to ashes. Water begins to boil. A broken leg mends itself.
1st, a new material is formed from the combination of grape juciea and alchahol. chemicla bond happens. wine made. FERMENTATION WITH ALCHAHOL. 2nd, Combustion is always a chemciql change. Combustion is when oxygen attaches itself to organic materiala nd relaeases fire. 3rd, Water boiling is a physical change. Can be restored. 4th, Your leg mending tho is chemcial. when you break something, that is phsyical.
62.State whether each of the following is a physical or chemical property of matter. Graphite conducts electricity. Bismuth, Bi, loses its iridescence upon melting. A copper penny is smushed into an embossed souvenir.
1st, that is a physical ability it can do. Doesn't change teh propoerties of the atom, just moves electrons form one place to another. No change in charge happens. Gains one, loses one. 2nd, Physical, if you freeze it againm, it will go back ot its original form. CAN BE REVERTED. 3rd, physical change, can be reverted back to oroginal form if needed.
48.You combine 50 mL of water with 50 mL of purified alcohol and get a total of 98 mL of the mixture. Please explain how this occurs.
48. The alcohol and the waterfall in between the openings of each other are similar to how if you had a bunch of big BB's and put a bunch of small BB's in, they would fill in the openings.
50.The leftmost diagram below shows the moving particles of a gas within a rigid container. Which of the three boxes on the right—(a), (b), or (c)—best represents this material upon the addition of heat?
50. B because the particles have sped up in that picture and when particles speed up, they are gaining thermal energy, and thus gaining heat. A they are slowing down so if anything theta are getting colder, and C is a different substance all together because the particles are a different size.
79.People often behave differently when they are in a group than when they are by themselves. Explain how this is similar to the behavior of atoms. Is this good news or bad news for the development of nanotechnology?
A macroscopic sample of an element contains billions upon billions of atoms bunched together. The properties exhibited by these grouped atoms are not necessarily the same as the properties of the atoms when isolated individually or in smaller groupings. Individual gold atoms, for example, appear red—not gold—and single sheets of graphite are transparent—not black. This is good news for nanotechnology because it means there are many nanoscopic properties yet to be discovered and exploited.
66.Each sphere in the diagrams below represents an atom. Joined spheres represent molecules. Which box contains a liquid phase? Why can't you assume that box B represents a lower temperature?
A> Gas phase because theya re taking up the whole box. B> In liquid/solid phase. HARD TO TELL. Can't say tehre was phase change becasue the 2nd box has new compounds, so that means they arent tyhe same. Prob same temp because there are still spome floating that are on thjeir own in the2nd box.
69.Oxygen atoms are used to make water molecules. Does this mean that oxygen, O2, and water, H2O, have similar properties? Why do we drown when we breathe in water, despite all the oxygen atoms present in this material?
All the oxygen water present is bound to hydrogen atoms making water molecules. Water is uniquely different from the elements oxygen, O2, and hydrogen, H2, from which it can be made. The oxygen our bodies are designed to breathe is gaseous molecular oxygen, O2. We drown when we breathe in water because it contains so little O2. Although they both contain oxygen, gaseous oxygen, O2, and water, H2O, are vastly different materials.
46.Is chemistry the study of submicroscopic, microscopic, or macroscopic matter, or of all three? Defend your answer.
All three because you are studying matter and how it is made so you need to know it inside and out.
78.How does a scanning probe microscope differ from an optical microscope?
An optical microscope is a microscope where you see something with your own eyes using a magnifying glass. A Scanning probe microscope is a microscope where you see something by seeing an image created by a needle being dragged across an atom.
Research that focuses on developing applications of knowledge gained through basic research.
Applied research
53.A skillet is lined with a thin layer of cooking oil followed by a layer of unpopped popcorn kernels. Upon heating, the kernels all pop, thereby escaping the skillet. Identify any physical or chemical changes.
As each kernel is heated, the water within each kernel is also heated to the point that it would turn into water vapor. The shell of the kernel, however, is air tight and this keeps the water as a superheated liquid. Eventually the pressure exerted by the superheated water exceeds the holding power of the kernel and the water bursts out as a vapor, which causes the kernel to pop. These are physical changes. The starches within the kernel, however, are also cooked by the high temperatures, and this is an example of a chemical change.
49.Which has stronger attractions among its submicroscopic particles: a solid at 25°C or a gas at 25°C? Explain.
At 25°C there is a certain amount of thermal energy available to all the submicroscopic particles of a material. If the attractions between the particles are not strong enough, the particles may separate from each other to form a gaseous phase. If the attractions are strong, however, the particles may be held together in the solid phase. We can assume, therefore, that the attractions among the submicroscopic particles of a material in its solid phase at 25°C are stronger than they are within a material that is a gas at this temperature.
Research that leads us to a greater understanding of how the natural world operates.
Basic research
45.Of physics, chemistry, and biology, which science is the most complex? Please explain.
Biology is based upon the principles of chemistry as applied to living organisms, while chemistry is based upon the principles of physics as applied to atoms and molecules. Physics is the study of the fundamental rules of nature, which more often than not are rather simple in their design and readily described by mathematical formula. Because biology sits at the top of these three sciences, it can be considered to be the most complex of them all.
59.In the winter Vermonters make a tasty treat called "sugar on snow" in which they pour boiled down maple syrup onto a scoop of clean fresh snow. As the syrup hits the snow, it forms a delicious taffy. Identify the physical changes involved in the making of sugar on snow. Identify any chemical changes.
Boiling down the maple syrup involves the evaporation of water. As the syrup hits the snow it warms the snow causing it to melt while the syrup becomes more viscous. These are all examples of physical changes. Interestingly, as the maple syrup is boiled the sugar within the syrup begins to caramelize, which is an example of a chemical change.
73.Which of the following boxes contains only an element? Which contains only a compound? How many different types of molecules are shown altogether in the three boxes?
Box "a" is a mixture. Box "b": compound. Box "c": element. There are three different types of molecules shown altogether in all three boxes: one with two open circles joined, one with a solid and open circle joined, and one with two solid circles joined.
The force of attraction between two atoms that holds them together.
Chemical bond
The formation of new substance(s) by rearranging the atoms of the original material(s).
Chemical change
A notation that indicates the composition of a compound, consisting of the atomic symbols for the different elements of the compound and numerical subscripts indicating the ratio in which the atoms combine.
Chemical formula
Any property that characterizes the ability of a substance to change into a different substance under specific conditions.
Chemical property
A term synonymous with chemical change.
Chemical reaction
The study of matter and the transformations it can undergo.
Chemistry
A material in which atoms of different elements are bonded to one another.
Compound
A notation that uses the atomic symbol and (sometimes) a numerical subscript to denote how many atoms are bonded in one unit of an element.
Elemental formula
52.A cotton ball is dipped in alcohol and wiped across a tabletop. Explain what happens to the alcohol molecules deposited on the tabletop. Is this a physical or chemical change?
Evaporate after killing germs. Physical change. Whenever there is a phase change, it's physical
57.Red Kool Aid crystals are added to a still glass of water. The crystals sink to the bottom. Twentyfour hours later, the entire solution is red even though no one stirred the water. Explain.
Even though the water appears to be still, the water molecules are bustling with kinetic energy. The red dye of the Kool-aid gets knocked around by these molecules to the point that the dye is eventually dispersed throughout the water. This is another case where the existence of molecules helps to explain the observed phenomenon.
56.Alcohol wiped across a tabletop rapidly disappears. What happens to the temperature of the tabletop? Why?
Get colder. Evaporation is a cooling process
70.Oxygen, O2, is certainly good for you. Does it follow that if small amounts of oxygen are good for you, then large amounts of oxygen would be especially good for you?
Getting too much oxygen will cause headaches, nausa, and for too much for a while: death. All things in moderation
74.What is the chemical formula for the compound dihydrogen sulfide?
H2S
54.A cotton ball dipped in alcohol is wiped across a tabletop. Would the resulting smell of the alcohol be more or less noticeable if the tabletop were much warmer? Explain.
Hotter=Evaporate. More particles in the air, stronger the smell
51.The leftmost diagram below shows two phases of a single substance. In the middle box, draw what these particles would look like if heat were taken away. In the box on the right, show what they would look like if heat were added. If each particle represents a water molecule, what is the temperature of the box on the left?
In the middle box you should have drawn all the particles aligned with each other as is seen in the left side of the first box. This would indicate the solid phase. In the box on the right, you should have drawn all the particles in random places as is seen in the right side of the first box. This represents the liquid phase. If each one of these particles represented a water molecule, the first box on the left would be indicative of ice melting, which occurs at 0°C.
A system for naming the countless number of possible compounds has been developed by the
International Union of Pure and Applied Chemistry (IUPAC).
43.If someone is able to explain an idea to you using small familiar words, what does this say about how well that person understands the idea?
It is easy to hide a lack of understanding by using big words you know others are not familiar with. If you have truly mastered a concept, you should be able to explain that concept to others using a language that is familiar to you both.
Guideline 3
Many compounds are not usually referred to by their systematic names. Instead, they are assigned common names that are more convenient or have been used traditionally for many years. Some common names are water for H2O, ammonia for NH3, and methane for CH4.
81.Medicines, such as pain relievers and antidepressants, are found in the drinking water supplies of many municipalities. How did these medicines get there? Does it matter that they are there? Should something be done about it? If so, what?
Many medicines are flushed down drains or toilets directly or after already having passed through the human body an into the urine. These drugs then end up in downstream water supplies. By the time they reach the downstream consumer their concentration is at a relatively low level. But this level is easily measured. Perhaps of greatest concern is the effect these low doses might have over the long term. Drinking a single glass of drug tainted water might not have a noticeable effect. But what if this water is consumed by an individual over his or her life time?
is anything that occupies space
Matter
An extremely small fundamental structure built of atoms.
Molecule
The manipulation of individual atoms or molecules.
Nanotechnology
77.What is the common name for oxygen oxide?
Oxygen, O2.
A change in a substance's physical properties, with no change in its chemical identity.
Physical change
Any physical attribute of a substance, such as color, density, or hardness.
Physical property
63.State whether each of the following is a physical or chemical property of matter. Carbon dioxide escapes when a soda can is opened. A bronze statue turns green. A silver spoon tarnishes.
Physical property: a; Chemical property: b, c
44.What is the best way to really prove to yourself that you understand an idea?
Put it into application in real life situations.
Members of the American Chemistry Council, who produce 90% of the chemicals manufactured in the United States, have adopted a program called
Responsible Care, in which they have pledged to manufacture without causing environmental damage.
A tool of nanotechnology that detects and characterizes the surface atoms of materials by way of an ultrathin probe tip, which is detected by laser light as it is mechanically dragged over the surface.
Scanning probe microscope
The realm of atoms and molecules, where objects are too small to be detected by optical microscopes.
Submicroscopic
61.Each night you measure your height just before going to bed. When you arise each morning, you measure your height again and consistently find that you are 1 inch taller than you were the night before, but only as tall as you were 24 hours ago! Is what happens to your body in this instance best described as a physical change or a chemical change? Be sure to try this activity if you haven't already.
That this process is so reversible suggests a physical change. As you sleep in a reclined position, pressure is taken off of the discs within your spinal column, which allows them to expand so that you are significantly taller in the morning. Astronauts returning from extended space visits may be up to two inches taller upon their return.62. They are all examples of physical properties.
47.You combine 50 mL of small BBs with 50 mL of large BBs and get a total of 90 mL of BBs of mixed sizes. Please explain how this occurs.
The 50 mL plus 50 mL do not add up to 100 mL because within the mix, many of the smaller BB's are able to fit within the pockets of space that were empty within the 50 mL of large BB's.
60.Oxygen, O2, has a boiling point of 90 K (−183°C), and nitrogen, N2, has a boiling point of 77 K (−196°C). Which is a liquid and which is a gas at 80 K (−193°C)?
The Oxygen is a liquid at room temperature because it has not reached its boiling point so therefore it cannot evaporate into gas form and it is cool enough to liquify. The nitrogen is a gas at this point because it has boiled and turned itself into a gas because the temperature is past its boiling point.
67.Is aging primarily an example of a physical or chemical change?
The changes that occur as we age involve the chemical reformation of our biomolecules. These are chemical changes.
Guideline 1
The name of the element farther to the left in the periodic table is followed by the name of the element farther to the right, with the suffix -ide added to the name of the latter:
55.Use Exercise 53 as an analogy to describe what occurs in Exercise 54. Does it make sense to think that the alcohol is made of very tiny particles (molecules) rather than being an infinitely continuous material?
The popcorn in the skillet can represent the alcohol molecules lying on the surface of the table top. As the kernels are heated they eventually leave the skillet. Likewise, as the alcohol molecules absorb heat from the table top they evaporate away from the table top. Do you see how easy it is to explain the disappearance of the alcohol by supposing the existence of alcohol molecules? We find that the concept of molecules can be used to readily explain so many different phenomena. This is why so many people came to believe in their existence many years before the discovery of direct evidence.
42.While visiting a foreign country, a foreignspeaking citizen tries to give you verbal directions to a local museum. After multiple attempts, he is unsuccessful. An onlooker sees your frustration and concludes that you are not smart enough to understand simple directions. Another onlooker sympathizes with you because he knows how difficult it is to navigate through an unfamiliar city. Which onlooker is correct?
The sympathizing one because you didn't understand the language. That doesnt make you inherently dumb, just unprepared.
75.What is the chemical name for a compound with the formula Ba3N2?
Tribarium dinitride, or more simply, barium nitride because no ratio other than three bariums to two nitrogens is possible.
71.Why isn't water classified as an element?
Water use to be classified as an element but that was before people recognized that the basic building block of matter are these tiny particles called atoms. Today, an element is identified as a material consisting only one kind of atom.
Guideline 2
When two or more compounds have different numbers of the same elements, prefixes are added to remove the ambiguity. The first four prefixes are mono- (one), di- (two), tri- (three), and tetra- (four). The prefix mono-, however, is commonly omitted from the beginning of the first word of the name:
72.If you eat metallic sodium or inhale chlorine gas, you stand a strong chance of dying. Let these two elements react with each other, however, and you can safely sprinkle the compound on your popcorn for better taste. What is going on?
When you combine these two elements into a compound, their toxic properties go away. A compound's atoms can act totally differently than how they act on their own.
58.With no one looking, you add 5 mL of a cinnamon solution to a blue balloon, which you tie shut. You also add 5 mL of fresh water to a red balloon, which you also tie shut. You heat the two balloons in a microwave until each inflates to about the size of a grapefruit. Your brother then comes along, examines the inflated balloons, and tells you that the blue balloon is the one containing the cinnamon. How did he know?
You can smell IT. Hotter=Evaporate. More particles in air= stronger smell
83.The British diplomat, physicist, and environmentalist John Ashton, in speaking to a group of scientists, stated (paraphrased): "There has to be much better communication between the world of science and the world of politics. Consider the different meanings of the word uncertainty. To scientists, it means uncertainty over the strength of a signal. To politicians it means 'go away and come back when you're certain.' " Pretend you are a scientist with strong but inconclusive evidence in support of impending climate change. How might you best persuade politicians to take action?
You probably should not spend too much time of showing the politicians your analysis of the data. If your credentials are good and you are respected among your peers, then the politicians will likely trust your assessments. Politicians will be much more interested in the impact such climate change will have on the general public, especially in terms of the economy. Your time would be well spent focusing on potential solutions to the problem. All the better if your solutions offered new jobs for the politician's constituents. John Ashton also said, "The more effort scientists put into how their message might be heard, how it might be manipulated and made mischief, the better. If we want to successfully respond to climate change we have to form it as part of the solution to the economic crisis."
rust is
a compound consisting of iron and oxygen atoms.
First, in a physical change, a change in appearance is the result of
a new set of conditions imposed on the same material. Restoring the original conditions restores the original appearance: frozen water melts upon warming.
65.Classify each change as physical or chemical. Even if you are incorrect in your assessment, you should be able to defend why you chose as you did. Grass grows. An infant gains 10 lb. A rock is crushed to powder.A tire is inflated with air.
a) chemical. b) chemical. c) physical. d) physical.
As we shall see in the next two sections, iron is
an element,
Generally, element is used in reference to
an entire macroscopic or microscopic sample,
The top down approach is
an extension of microtechnology techniques to smaller and smaller scales
All three of these transformations involve a change in the way the
atoms in the molecules are chemically bonded to one another
Copper has the chemical property of reacting with carbon dioxide and water to form a greenish
blue solid known as -patina.
80.How is chemistry similar to nanotechnology? How is it different?
both have to do with molevules andatoms. Chemistry is a gorup of atoms. nanotechnology is individual atoms
The bottom up approach involves
building nanosized objects atom by atom
The methane of natural gas has the chemical property of reacting with oxygen to produce
carbon dioxide and water, along with appreciable heat energy
Thus, the term chemical change means the same thing as
chemical reaction
82.Your friend smells cinnamon coming from an inflated rubber balloon containing cinnamon extract. You tell him that the cinnamon molecules are passing through the micropores of the balloon. He accepts the idea that the balloon contains micropores but insists that he is simply smelling cinnamonflavored air. You explain that scientists have discovered that gases are made of molecules, but that's not good enough for him. He needs to see the evidence for himself. How might you lead him to accept the concept of molecules?
cinamon and air molcules can escape. not cinampn flavoed ir but rather air cotaing both while scaping
Compounds have physical and chemical properties that are
completely different from the properties of their elemental components.
68.Octane is a component of gasoline. It reacts with oxygen, O2, to form carbon dioxide and water. Is octane an element or a compound? How can you tell?
coumpound becayse Water and cabron Dioxide have Hydrogen and carbon, something taht oxygen does not posess, so out of order of deduction, Octance has CArbon and Hydrogen making it a compound
A wholly new approach involves
designing logic boards in which molecules (not electric circuits) read, process, and write information. One molecule that has proved most promising for such molecular computation is DNA, the same molecule that holds our genetic code
The addition of heat causes these vibrations to increase until, at a certain temperature, the vibrations are rapid enough to
disrupt the fixed arrangements. Rock melts into magma (a topic of much discussion in Part 3). Likewise, ice melts into water.
The fundamental unit of an element is indicated by its
elemental formula
How can you determine whether an observed change is physical or chemical? This can be tricky because
in both cases, changes in physical appearance occur.
The rusting of a car, by contrast, is the result of the transformation of iron to rust. This is a chemical change because
iron and rust are two different materials, each consisting of a different arrangement of atoms.
At the microscopic level, physical structure is so fine that
it can be seen only with a microscope.
Chemistry is often described as a central science because
it touches all the other sciences.
The more transistors they could squeeze into a circuit, the more powerful the
logic board
The ultimate expert on nanotechnology is
nature.
76.What is the common name for dioxygen oxide?
ozone
The freezing of water is a _______ because liquid water and frozen water are both forms of water—only the orientation of the water molecules to one another changes.
physical change
coffee and tea are decaffeinated using carbon dioxide in a fourth phase of matter known as a supercritical fluid. This phase behaves like a gaseous liquid, which is attained by adding lots of
pressure and heat.
In the language of chemistry, materials undergoing a chemical change are said to be
reacting.
At the macroscopic level, matter is large enough to be
seen, measured, and handled
Applying pressure to a gas does what
squeezes the gas particles closer together, which decreases the volume.
In solid matter, such as rock, the attractions between particles are
strong enough to hold all the particles together in some fixed three-dimensional arrangement.
coffee and tea are decaffeinated using carbon dioxide in a fourth phase of matter known as a
supercritical fluid.
Second, in a chemical change, a change in appearance is the result of
the formation of a new material that has its own unique set of physical properties.
Nanotechnology generally concerns
the manipulations of objects from 1 to 100 nanometers in size.
The race thus began to squeeze more and more transistors together into tinier and tinier circuits. The scales achieved were in the realm of
the micron ( 10−6 m): thus the term microtechnology.
Technological advances have recently brought us past the realm of microns to the realm of
the nanometer ( 10^−9 m), which is the scale of individual atoms and molecules—a realm where we have reached the basic building blocks of matter.
An interesting discovery of nanoscience is that
the properties of a material at the level of its atoms can be different from its properties in bulk quantities.
atom is used when speaking of
the submicroscopic particles in the sample.
There are two main approaches to building nanoscale materials and devices:
top-down and bottom-up
By becoming nanotechnology experts ourselves, we would be well equipped to
understand exact causes of nearly any disease or disorder (aging included) and empowered to develop innovative cures.
Matter in the gaseous phase therefore occupies much more
volume than it does in the solid or liquid phase.