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NIU CHEM 210 - Components of Matter and Laws
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CHEM 210 1st Edition Lecture 5 Outline of Last Lecture I. Units of MeasurementsA. SI Units of MeasurementII. Converting Between MeasurementsIII. Temperature ScalesOutline of Current LectureIV. The Components of Matter V. Law of Mass ConservationVI. Law of Definite or Constant CompositionVII. Law of Multiple Proportions Current LectureThere are a few definitions you need to know that are associated with the components of matter. An element is the simplest type of substance with unique physical and chemical properties. Elements consist of only one type of atom. Molecules on the other hand are a group of atoms bonded together. Water is a molecule that consists of two hydrogen atoms and one oxygen atom. Compounds are one or more elements chemically combined. Mixtures are one or more elements or compounds that are physically intermingled or mixed. There are two types of mixtures, heterogeneous and homogeneous mixtures. Heterogeneous mixtures occur when you can separate each substance, such as a bag of mixed nuts. Homogeneous mixtures are mixtures that are uniform throughout and cannot be separated easily, such as chocolate milk. There are certain mixtures that when separate elements, are very reactive, but create necessary components we need. For example, sodium (a reactive metal) and chlorine (a hazardous gas) chemically combine together to from sodium chloride (a stable solid), which is salt. Sodium and Chlorine apart are very dangerous elements, however when combined, they form an ingredient we need in our body. .85 percent of salt concentration is needed in each person’s body. These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.The Law of Mass Conservation is a law claiming the total mass of a substance does not change during a chemical reaction. Reactant 1’s mass plus reactant 2’s mass must equal the products mass. For example, Calcium (Ca) + Carbon Dioxide (CO2), form Calcium Carbonate (CaCO3)The Law of Definite (or constant) Composition states that no matter the source, aparticular compound is composed of the same elements in the same parts (fractions) by mass.Ex; Calcium Carbonate8.0 grams Ca + 2.4 grams C + 9.6 grams O2 all equal to 20.0 grams. To get parts per mass, you simply take each amount of grams of the substance, and divide by the total amount of grams.8.0 grams Ca / 20.0 grams total = .40 Ca2.4 grams C / 20.0 grams total = .12 C9.6 grams O2 / 20.0 grams total = .48 O2All should equal 1.00 parts per mass!Finally, to get percent by mass, you convert the decimals into percentages and they should all equal to 100..40 Ca = 40%.12 C = 12%.48 O2= 48%The Law of Multiple Proportions states that is elements A and B react to from two compounds, the different masses of B that combine with a fixed mass of A, can be explained as a ratio of small whole numbers.For example, Carbon Oxide I: 57.1% O2 and 42.9% CCarbon Oxide II: 72.7% O2 and 27.3% CAssume you have 100 grams of each component.You would simply put these values into proportions to end up with a ratio of small numbers.g O / g C = 57.1 / 42.9 = 1.33g O / g C = 72.7 / 27.3 = 2.66So, 2.66 g O/g C in II = 21.33 g 0/g C in I = 1So the ratio then equals


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NIU CHEM 210 - Components of Matter and Laws

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