After an Atom Is Combined Can It Be Seperated Again
Chapter 1. Essential Ideas
1.ii Phases and Nomenclature of Matter
Learning Objectives
By the end of this section, yous will be able to:
- Depict the basic backdrop of each physical state of thing: solid, liquid, and gas
- Define and requite examples of atoms and molecules
- Classify thing equally an chemical element, compound, homogeneous mixture, or heterogeneous mixture with regard to its physical state and composition
- Distinguish between mass and weight
- Employ the police force of conservation of matter
Matter is defined equally annihilation that occupies space and has mass, and it is all around us. Solids and liquids are more manifestly matter: Nosotros can see that they take up space, and their weight tells usa that they have mass. Gases are also matter; if gases did not accept upwardly space, a balloon would stay collapsed rather than inflate when filled with gas.
Solids, liquids, and gases are the three states of matter ordinarily found on earth (Figure one). A solid is rigid and possesses a definite shape. A liquid flows and takes the shape of a container, except that it forms a flat or slightly curved upper surface when acted upon past gravity. (In zip gravity, liquids presume a spherical shape.) Both liquid and solid samples have volumes that are very well-nigh independent of force per unit area. A gas takes both the shape and volume of its container.
A fourth state of matter, plasma, occurs naturally in the interiors of stars. A plasma is a gaseous state of matter that contains appreciable numbers of electrically charged particles (Effigy two). The presence of these charged particles imparts unique properties to plasmas that justify their classification as a state of matter singled-out from gases. In add-on to stars, plasmas are establish in some other high-temperature environments (both natural and man-made), such equally lightning strikes, certain tv screens, and specialized analytical instruments used to find trace amounts of metals.
In a tiny cell in a plasma television, the plasma emits ultraviolet calorie-free, which in turn causes the display at that location to appear a specific color. The composite of these tiny dots of color makes up the image that you lot see. Lookout this video to learn more about plasma and the places you encounter information technology.
Some samples of matter appear to have backdrop of solids, liquids, and/or gases at the same time. This can occur when the sample is composed of many small pieces. For case, nosotros tin pour sand as if it were a liquid considering it is equanimous of many small grains of solid sand. Thing tin too accept properties of more than i state when it is a mixture, such as with clouds. Clouds appear to behave somewhat like gases, only they are actually mixtures of air (gas) and tiny particles of water (liquid or solid).
The mass of an object is a measure out of the amount of matter in it. I way to measure an object'due south mass is to mensurate the force it takes to accelerate the object. It takes much more strength to accelerate a car than a bike because the car has much more mass. A more than common manner to determine the mass of an object is to utilise a balance to compare its mass with a standard mass.
Although weight is related to mass, it is non the same thing. Weight refers to the force that gravity exerts on an object. This force is directly proportional to the mass of the object. The weight of an object changes every bit the force of gravity changes, only its mass does non. An astronaut's mass does non modify just because she goes to the moon. But her weight on the moon is simply one-sixth her globe-jump weight because the moon's gravity is only i-6th that of the earth's. She may feel "weightless" during her trip when she experiences negligible external forces (gravitational or any other), although she is, of course, never "massless."
The law of conservation of matter summarizes many scientific observations about matter: It states that there is no detectable change in the full quantity of matter present when matter converts from one type to another (a chemical change) or changes among solid, liquid, or gaseous states (a physical alter). Brewing beer and the operation of batteries provide examples of the conservation of matter (Figure three). During the brewing of beer, the ingredients (water, yeast, grains, malt, hops, and carbohydrate) are converted into beer (water, alcohol, carbonation, and flavoring substances) with no actual loss of substance. This is most clearly seen during the bottling procedure, when glucose turns into ethanol and carbon dioxide, and the full mass of the substances does not change. This tin too be seen in a lead-acid motorcar battery: The original substances (pb, atomic number 82 oxide, and sulfuric acid), which are capable of producing electricity, are changed into other substances (pb sulfate and h2o) that do not produce electricity, with no change in the actual amount of matter.
Although this conservation police holds true for all conversions of matter, disarming examples are few and far between because, exterior of the controlled conditions in a laboratory, we seldom collect all of the material that is produced during a particular conversion. For instance, when y'all eat, digest, and assimilate nutrient, all of the matter in the original food is preserved. But because some of the matter is incorporated into your torso, and much is excreted as various types of waste, it is challenging to verify by measurement.
Atoms and Molecules
An atom is the smallest particle of an element that has the properties of that element and can enter into a chemical combination. Consider the element gold, for example. Imagine cutting a gold nugget in half, and so cutting one of the halves in half, and repeating this process until a piece of gilded remained that was so pocket-sized that information technology could not be cut in half (regardless of how tiny your pocketknife may be). This minimally sized piece of gold is an atom (from the Greek atomos, meaning "indivisible") (Figure 4). This atom would no longer be gold if it were divided whatever further.
The kickoff suggestion that thing is composed of atoms is attributed to the Greek philosophers Leucippus and Democritus, who adult their ideas in the 5th century BCE. Withal, it was not until the early nineteenth century that John Dalton (1766–1844), a British schoolteacher with a keen interest in science, supported this hypothesis with quantitative measurements. Since that time, repeated experiments accept confirmed many aspects of this hypothesis, and it has become one of the central theories of chemical science. Other aspects of Dalton'south diminutive theory are withal used but with minor revisions (details of Dalton's theory are provided in the affiliate on atoms and molecules).
An atom is and then pocket-size that its size is difficult to imagine. One of the smallest things we tin can run into with our unaided eye is a single thread of a spider web: These strands are near 1/10,000 of a centimeter (0.0001 cm) in bore. Although the cross-section of one strand is almost impossible to see without a microscope, information technology is huge on an diminutive scale. A single carbon atom in the web has a diameter of near 0.000000015 centimeter, and it would take most 7000 carbon atoms to span the diameter of the strand. To put this in perspective, if a carbon atom were the size of a dime, the cross-section of one strand would be larger than a football field, which would require well-nigh 150 million carbon atom "dimes" to cover it. (Figure 5) shows increasingly shut microscopic and atomic-level views of ordinary cotton.
An cantlet is then lite that its mass is besides hard to imagine. A billion lead atoms (1,000,000,000 atoms) weigh virtually 3 × 10−thirteen grams, a mass that is far also low-cal to be weighed on even the globe's almost sensitive balances. Information technology would require over 300,000,000,000,000 lead atoms (300 trillion, or 3 × 1014) to be weighed, and they would counterbalance only 0.0000001 gram.
Information technology is rare to find collections of individual atoms. Only a few elements, such as the gases helium, neon, and argon, consist of a drove of private atoms that move about independently of 1 another. Other elements, such as the gases hydrogen, nitrogen, oxygen, and chlorine, are composed of units that consist of pairs of atoms (Effigy 6). One form of the element phosphorus consists of units equanimous of four phosphorus atoms. The chemical element sulfur exists in various forms, one of which consists of units composed of eight sulfur atoms. These units are called molecules. A molecule consists of two or more atoms joined by potent forces called chemical bonds. The atoms in a molecule motility around every bit a unit, much like the cans of soda in a 6-pack or a bunch of keys joined together on a single fundamental ring. A molecule may consist of two or more than identical atoms, equally in the molecules establish in the elements hydrogen, oxygen, and sulfur, or it may consist of two or more different atoms, as in the molecules institute in h2o. Each h2o molecule is a unit of measurement that contains two hydrogen atoms and one oxygen atom. Each glucose molecule is a unit that contains half-dozen carbon atoms, 12 hydrogen atoms, and 6 oxygen atoms. Like atoms, molecules are incredibly small and light. If an ordinary glass of h2o were enlarged to the size of the earth, the water molecules inside it would exist about the size of golf balls.
Classifying Matter
We can classify affair into several categories. Two broad categories are mixtures and pure substances. A pure substance has a constant composition. All specimens of a pure substance have exactly the aforementioned makeup and properties. Whatever sample of sucrose (table sugar) consists of 42.ane% carbon, 6.5% hydrogen, and 51.four% oxygen by mass. Any sample of sucrose also has the same physical properties, such equally melting bespeak, color, and sweetness, regardless of the source from which it is isolated.
We can split up pure substances into two classes: elements and compounds. Pure substances that cannot be broken down into simpler substances by chemical changes are called elements. Iron, silverish, gold, aluminum, sulfur, oxygen, and copper are familiar examples of the more than than 100 known elements, of which virtually xc occur naturally on the globe, and two dozen or so have been created in laboratories.
Pure substances that can be cleaved down past chemic changes are called compounds. This breakdown may produce either elements or other compounds, or both. Mercury(II) oxide, an orange, crystalline solid, tin be broken down by rut into the elements mercury and oxygen (Figure 7). When heated in the absenteeism of air, the compound sucrose is broken down into the element carbon and the compound water. (The initial stage of this process, when the sugar is turning brown, is known as caramelization—this is what imparts the feature sugariness and nutty flavor to caramel apples, caramelized onions, and caramel). Argent(I) chloride is a white solid that tin be broken down into its elements, silver and chlorine, by absorption of lite. This property is the basis for the use of this compound in photographic films and photochromic eyeglasses (those with lenses that darken when exposed to light).
Many compounds interruption down when heated. This site shows the breakup of mercury oxide, HgO. Y'all tin can also view an example of the photochemical decomposition of silver chloride (AgCl), the ground of early photography.
The backdrop of combined elements are different from those in the free, or uncombined, country. For case, white crystalline carbohydrate (sucrose) is a compound resulting from the chemical combination of the chemical element carbon, which is a black solid in i of its uncombined forms, and the 2 elements hydrogen and oxygen, which are colorless gases when uncombined. Free sodium, an element that is a soft, shiny, metal solid, and free chlorine, an element that is a yellow-green gas, combine to form sodium chloride (tabular array salt), a chemical compound that is a white, crystalline solid.
A mixture is composed of two or more types of affair that can be present in varying amounts and can exist separated by physical changes, such every bit evaporation (yous will learn more about this later). A mixture with a composition that varies from point to point is called a heterogeneous mixture. Italian dressing is an example of a heterogeneous mixture (Figure 8). Its composition tin can vary because nosotros can make it from varying amounts of oil, vinegar, and herbs. It is not the same from point to point throughout the mixture—one drib may be mostly vinegar, whereas a dissimilar driblet may be mostly oil or herbs because the oil and vinegar carve up and the herbs settle. Other examples of heterogeneous mixtures are chocolate chip cookies (we can see the separate bits of chocolate, basics, and cookie dough) and granite (nosotros tin see the quartz, mica, feldspar, and more).
A homogeneous mixture, besides called a solution, exhibits a uniform composition and appears visually the aforementioned throughout. An example of a solution is a sports drink, consisting of water, sugar, coloring, flavoring, and electrolytes mixed together uniformly (Figure eight). Each drop of a sports drink tastes the same because each driblet contains the same amounts of h2o, sugar, and other components. Note that the composition of a sports drink can vary—information technology could be made with somewhat more or less sugar, flavoring, or other components, and nonetheless exist a sports drink. Other examples of homogeneous mixtures include air, maple syrup, gasoline, and a solution of salt in water.
Although there are merely over 100 elements, tens of millions of chemical compounds upshot from unlike combinations of these elements. Each chemical compound has a specific limerick and possesses definite chemical and physical properties by which we can distinguish it from all other compounds. And, of grade, there are innumerable ways to combine elements and compounds to grade different mixtures. A summary of how to distinguish between the diverse major classifications of matter is shown in (Figure ix).
Eleven elements make up well-nigh 99% of the globe's crust and temper (Table 1). Oxygen constitutes near one-one-half and silicon virtually one-quarter of the total quantity of these elements. A majority of elements on earth are establish in chemical combinations with other elements; about one-quarter of the elements are also found in the costless country.
Chemical element | Symbol | Percentage Mass | Chemical element | Symbol | Pct Mass | |
---|---|---|---|---|---|---|
oxygen | O | 49.20 | chlorine | Cl | 0.xix | |
silicon | Si | 25.67 | phosphorus | P | 0.11 | |
aluminum | Al | 7.50 | manganese | Mn | 0.09 | |
iron | Iron | 4.71 | carbon | C | 0.08 | |
calcium | Ca | 3.39 | sulfur | Due south | 0.06 | |
sodium | Na | two.63 | barium | Ba | 0.04 | |
potassium | K | 2.40 | nitrogen | Due north | 0.03 | |
magnesium | Mg | 1.93 | fluorine | F | 0.03 | |
hydrogen | H | 0.87 | strontium | Sr | 0.02 | |
titanium | Ti | 0.58 | all others | – | 0.47 | |
Table ane. Elemental Limerick of Earth |
Decomposition of Water / Production of Hydrogen
Water consists of the elements hydrogen and oxygen combined in a 2 to one ratio. Water tin can be broken downwards into hydrogen and oxygen gases by the improver of free energy. Ane way to do this is with a battery or power supply, as shown in (Effigy ten).
The breakup of h2o involves a rearrangement of the atoms in h2o molecules into unlike molecules, each equanimous of 2 hydrogen atoms and two oxygen atoms, respectively. Two h2o molecules form one oxygen molecule and ii hydrogen molecules. The representation for what occurs, [latex]2\text{H}_2\text{O}(l) \rightarrow 2\text{H}_2(g) + \text{O}_2(g)[/latex], volition exist explored in more depth in later chapters.
The two gases produced accept distinctly different properties. Oxygen is non flammable simply is required for combustion of a fuel, and hydrogen is highly combustible and a potent free energy source. How might this knowledge exist applied in our world? 1 application involves enquiry into more than fuel-efficient transportation. Fuel-jail cell vehicles (FCV) run on hydrogen instead of gasoline (Effigy 11). They are more efficient than vehicles with internal combustion engines, are nonpolluting, and reduce greenhouse gas emissions, making us less dependent on fossil fuels. FCVs are non yet economically viable, however, and current hydrogen product depends on natural gas. If we can develop a process to economically decompose water, or produce hydrogen in another environmentally audio style, FCVs may be the way of the future.
Chemistry of Cell Phones
Imagine how different your life would exist without cell phones (Effigy 12) and other smart devices. Cell phones are made from numerous chemic substances, which are extracted, refined, purified, and assembled using an all-encompassing and in-depth understanding of chemical principles. About 30% of the elements that are establish in nature are found within a typical smart phone. The case/body/frame consists of a combination of sturdy, durable polymers comprised primarily of carbon, hydrogen, oxygen, and nitrogen [acrylonitrile butadiene styrene (ABS) and polycarbonate thermoplastics], and light, stiff, structural metals, such as aluminum, magnesium, and iron. The display screen is made from a specially toughened glass (silica glass strengthened by the improver of aluminum, sodium, and potassium) and coated with a material to make it conductive (such equally indium tin oxide). The circuit board uses a semiconductor material (usually silicon); usually used metals similar copper, tin, silver, and gold; and more unfamiliar elements such as yttrium, praseodymium, and gadolinium. The battery relies upon lithium ions and a multifariousness of other materials, including atomic number 26, cobalt, copper, polyethylene oxide, and polyacrylonitrile.
Key Concepts and Summary
Matter is anything that occupies space and has mass. The basic edifice block of matter is the atom, the smallest unit of an element that can enter into combinations with atoms of the aforementioned or other elements. In many substances, atoms are combined into molecules. On earth, matter commonly exists in iii states: solids, of fixed shape and book; liquids, of variable shape but stock-still volume; and gases, of variable shape and volume. Nether high-temperature atmospheric condition, affair as well can exist as a plasma. Most thing is a mixture: It is composed of two or more types of matter that tin can be nowadays in varying amounts and tin be separated past physical means. Heterogeneous mixtures vary in composition from point to point; homogeneous mixtures have the same composition from point to indicate. Pure substances consist of only i type of matter. A pure substance can be an element, which consists of only one type of atom and cannot exist broken down past a chemic change, or a compound, which consists of two or more types of atoms.
Chemistry End of Chapter Exercises
- Why practise we use an object'southward mass, rather than its weight, to indicate the corporeality of affair it contains?
- What properties distinguish solids from liquids? Liquids from gases? Solids from gases?
- How does a heterogeneous mixture differ from a homogeneous mixture? How are they similar?
- How does a homogeneous mixture differ from a pure substance? How are they similar?
- How does an element differ from a compound? How are they similar?
- How practice molecules of elements and molecules of compounds differ? In what ways are they similar?
- How does an atom differ from a molecule? In what means are they similar?
- Many of the items you purchase are mixtures of pure compounds. Select 3 of these commercial products and set a list of the ingredients that are pure compounds.
- Classify each of the following equally an element, a compound, or a mixture:
(a) copper
(b) water
(c) nitrogen
(d) sulfur
(e) air
(f) sucrose
(g) a substance equanimous of molecules each of which contains ii iodine atoms
(h) gasoline
- Classify each of the post-obit every bit an element, a compound, or a mixture:
(a) iron
(b) oxygen
(c) mercury oxide
(d) pancake syrup
(due east) carbon dioxide
(f) a substance composed of molecules each of which contains one hydrogen atom and one chlorine cantlet
(grand) baking soda
(h) blistering powder
- A sulfur cantlet and a sulfur molecule are not identical. What is the difference?
- How are the molecules in oxygen gas, the molecules in hydrogen gas, and water molecules similar? How do they differ?
- We refer to astronauts in space as weightless, but not without mass. Why?
- As nosotros bulldoze an motorcar, nosotros don't think about the chemicals consumed and produced. Fix a list of the principal chemicals consumed and produced during the performance of an automobile.
- Matter is everywhere around us. Make a listing by name of fifteen different kinds of matter that you encounter every day. Your list should include (and label at to the lowest degree one example of each) the post-obit: a solid, a liquid, a gas, an element, a compound, a homogenous mixture, a heterogeneous mixture, and a pure substance.
- When elemental iron corrodes it combines with oxygen in the air to ultimately form ruby brownish fe(III) oxide which nosotros phone call rust. (a) If a shiny iron nail with an initial mass of 23.2 g is weighed after being coated in a layer of rust, would you lot expect the mass to have increased, decreased, or remained the same? Explain. (b) If the mass of the atomic number 26 boom increases to 24.1 thou, what mass of oxygen combined with the iron?
- Equally stated in the text, convincing examples that demonstrate the law of conservation of affair exterior of the laboratory are few and far between. Betoken whether the mass would increase, subtract, or stay the aforementioned for the following scenarios where chemical reactions take place:
(a) Exactly i pound of bread dough is placed in a blistering tin. The dough is cooked in an oven at 350 °F releasing a wonderful aroma of freshly baked bread during the cooking process. Is the mass of the broiled loaf less than, greater than, or the same as the one pound of original dough? Explain.
(b) When magnesium burns in air a white flaky ash of magnesium oxide is produced. Is the mass of magnesium oxide less than, greater than, or the same as the original piece of magnesium? Explain.
(c) Antoine Lavoisier, the French scientist credited with beginning stating the police force of conservation of matter, heated a mixture of tin and air in a sealed flask to produce tin oxide. Did the mass of the sealed flask and contents decrease, increment, or remain the aforementioned afterwards the heating?
- Yeast converts glucose to ethanol and carbon dioxide during anaerobic fermentation every bit depicted in the simple chemical equation here:
[latex]\text{glucose} \rightarrow \text{ethanol + carbon dioxide}[/latex]
(a) If 200.0 g of glucose is fully converted, what will exist the total mass of ethanol and carbon dioxide produced?
(b) If the fermentation is carried out in an open up container, would you expect the mass of the container and contents after fermentation to exist less than, greater than, or the aforementioned every bit the mass of the container and contents before fermentation? Explicate.
(c) If 97.7 g of carbon dioxide is produced, what mass of ethanol is produced?
Glossary
- atom
- smallest particle of an element that can enter into a chemical combination
- compound
- pure substance that can exist decomposed into two or more elements
- chemical element
- substance that is composed of a single type of atom; a substance that cannot be decomposed by a chemical modify
- gas
- state in which matter has neither definite volume nor shape
- heterogeneous mixture
- combination of substances with a composition that varies from indicate to betoken
- homogeneous mixture
- (also, solution) combination of substances with a limerick that is uniform throughout
- liquid
- state of thing that has a definite book merely indefinite shape
- law of conservation of thing
- when matter converts from one type to another or changes course, there is no detectable change in the total amount of matter present
- mass
- fundamental holding indicating amount of matter
- affair
- anything that occupies infinite and has mass
- mixture
- matter that can be separated into its components by concrete means
- molecule
- bonded collection of two or more than atoms of the same or different elements
- plasma
- gaseous land of matter containing a large number of electrically charged atoms and/or molecules
- pure substance
- homogeneous substance that has a abiding composition
- solid
- country of matter that is rigid, has a definite shape, and has a fairly abiding volume
- weight
- force that gravity exerts on an object
Solutions
Answers for Chemical science End of Chapter Exercises
2. Liquids can alter their shape (menstruum); solids tin can't. Gases can undergo large book changes as pressure level changes; liquids do not. Gases menses and change volume; solids practise not.
4. The mixture can have a variety of compositions; a pure substance has a definite limerick. Both have the aforementioned composition from indicate to indicate.
6. Molecules of elements contain merely 1 type of atom; molecules of compounds contain two or more types of atoms. They are similar in that both are comprised of ii or more atoms chemically bonded together.
8. Answers will vary. Sample reply: Gatorade contains water, sugar, dextrose, citric acrid, salt, sodium chloride, monopotassium phosphate, and sucrose acetate isobutyrate.
10. (a) element; (b) chemical element; (c) chemical compound; (d) mixture, (e) compound; (f) chemical compound; (yard) chemical compound; (h) mixture
12. In each case, a molecule consists of 2 or more combined atoms. They differ in that the types of atoms change from ane substance to the next.
fourteen. Gasoline (a mixture of compounds), oxygen, and to a bottom extent, nitrogen are consumed. Carbon dioxide and water are the main products. Carbon monoxide and nitrogen oxides are produced in lesser amounts.
16. (a) Increased as information technology would have combined with oxygen in the air thus increasing the amount of matter and therefore the mass. (b) 0.9 thousand
18. (a) 200.0 g; (b) The mass of the container and contents would subtract as carbon dioxide is a gaseous product and would leave the container. (c) 102.iii g
Source: https://opentextbc.ca/chemistry/chapter/phases-and-classification-of-matter/
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