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NIU CHEM 210 - Exam 1 Study Guide

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CHEM 210 1nd EditionExam # 1 Study Guide Lectures: 1 - 11Lecture 1 (January 12)Why should we study chemistry? What is the scientific method and what are the steps to it? Chemistry is life. Chemistry is all around us, even in our bodies! Chemical reactions are constantly taking place in our bodies, such as digestion. Chemistry is also the reason why there are colors, tastes, flavors and scents. All living things consists of matter, which is then broken down into molecules. Moleculesare broken down into atoms, and within and atom consists protons and neutrons which le in thenucleus. Electrons surround the nucleus. The scientific method is a method used to test and verify experiments. The first step is to create a testable hypothesis or prediction. Within the hypothesis can exist qualitative or quantitative data. Quantitative data are numerical observations while qualitative data are non-numerical observations. If a hypothesis is tested a numerous amount of times with the same outcome, it could turn into a law. A theory is then used to explain the law.Lecture 2 (January 14) What is matter, and what are the different phases of matter? What are compounds and elements? What are mixtures and the different kinds of mixtures? What are physical and chemical properties, as well as energy?Matter by definition is anything that has mass and takes up space. The 3 phases of matter are liquids, gasses and solids. Liquids have definite volumes, but indefinite shapes. Gases have indefinite shapes and indefinite volumes. Solids have both definite shapes and definite volumes. Elements are matter that has only one kind of atom, and occur naturally in nature. Examples are the elements listed on the periodic table. Compounds are formed by 2 or more elements combining. An example is water, (H2O).Mixtures are composed of two or more substances. Substances are pure forms of matter where every sample contains the same kinds of atoms in the same proportions. Mixtures can then be classified further as homogeneous or heterogeneous. An example of a heterogeneous mixture is pizza, where the components can be separated easily. An example of a homogeneous mixture is chocolate milk, where the milk and chocolate are mixed uniformly and are more difficult to separate. Properties are characteristics that give each substance a unique identity. Properties can be divided as either chemical or physical. Physical properties are described as color, melting point, boiling point and density. Chemical properties include flammability, corrosiveness, or anything that changes the chemical makeup of a substance. Extensive physical properties depend on the amount of matter present such as volume or mass. Intensive physical propertiesdo not depend on the amount of matter present and are instead the color, melting point and boiling point. Energy is the capacity to do work. There are two common types of energy which are potential and kinetic. Potential energy stored energy and is due to the position of the object or energy from a chemical reaction. Kinetic energy is the energy of motion, and is used when the object is in motion. Gravitational energy is potential energy gained when a lifted weight is converted to kinetic energy as the weight falls. The object is pulled down by a gravitational force. Lecture 3 (January 16)What are different units of measurements, such as SI units? How do you convert between these measurements? What are the different temperature scales and how do you convert between them?Common SI base units include kilograms that are used to describe mass, meters used forlength, seconds used for time, kelvin used for temperature, amperes for electrical currents, moles for the amount of a substance, and candela for luminous intensity. SI base units can be converted multiple times and are used for most conversion problems in chemistry. To solve conversion problems, you begin with your given quantity and multiply that by the desired unit over the given unit. This cancels out the units of the given quantity and leaves you with the units for the desired quantity. Temperature scales include Kelvin, Celsius, and Fahrenheit. Kelvin is the absolute temperature scale, beginning at absolute 0 and only has positive values. Celsius or centigrade,freezes at 0 degrees and boils at 100 degrees. Fahrenheit freezes at 32 degrees and boils ar 212degrees. To convert from Celsius to Kelvin, you add 273.15 degrees to Celsius.To convert from Celsius to Fahrenheit, it would be 5/9 (F - 32).To convert from Fahrenheit to Celsius, it would be 5/9 (C + 32) Lecture 4 (January 21)What are significant figures, and the rules for using them? What is the difference between precision and accuracy? What is systematic error and random error?Significant figures are important when solving numerical problems in chemistry. Your answer should include the same number of significant figures as the value with the least number of numerical values. Any non-zero digit is always significant. The zeros after a demical point are significant. Zeros to the left of decimal points are not significant but zeros in between 2 non-zeros are significant. Examples;- 3.456 has 4 significant figures- 11.00 has 4 significant figures- 0.00034 has 2 significant figures- 20000000 has 1 significant figure- 12.0067 has 6 significant figuresWhen adding and subtracting, the answer should have the same number of decimal places as there are in the measurement with the fewest decimal places. When multiplying and dividing, the answer should have the same amount of significant figures as the value with the least amount of significant figures.Precision/AccuracyPrecision refers to reproducibility or how close the measurements are to each other. Accuracy refers to how close a measurement is to the real value. For example, if a student did an experiment where he or she was supposed to achieve a value of 4.34, but instead they received values that were 1.22, 1.24, and 1.223, the student would be precise but not accurate. Systematic Error/Random ErrorSystematic error occurs when values are higher or lower than the actual value, while random error occurs when some values are lower and some are higher than the actual value. Lecture 5 (January 23)What are the different components of matter? What is the law of conservation of mass?What is the law of definite or constant composition? What is the law of multiple proportions? An element is


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