CHEM210 X-rays old-time remedies reading

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Please read the following article:

http://www.bbc.co.uk/news/science-environment-2206...

and write a response in 1-2 pages (minimum of 300 words, maximum of 600 words, not including the exam question) using the 3-2-1 format described below:

3: Find 3 concepts from within the article and relate them to 3 concepts within CHEM 210 we have discussed in class and cite 3 textbook references using the chapter and page number.

2: Find 2 concepts from within the article that you want to know more about (i.e. muddy points, have questions about, did not quite understand).

1: Write an exam question with the answer about 1 concept discussed from within the article. The exam question must be well thought out and appropriate to the subject matter.

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Chapter 1. Chemistry:

Matter on the Atomic Scale
1.1 What is Chemistry?
1.2 Classification of Matter
1.3 Units and Measurement
1.4 Unit Conversions

Chapter 1 introduces the fundamental components of matter, the different types of structures they can make when they join together, and the types of changes they undergo.

Chapter 1. Chemistry: Matter on the Atomic Scale 1.1 1.2 1.3 1.4 What is Chemistry? Classification of Matter Units and Measurement Unit Conversions Chapter 1 introduces the fundamental components of matter, the different types of structures they can make when they join together, and the types of changes they undergo. Interactive Figure 1.1.1 - Understand the Scale of Science • Macroscopic scale – Matter that can be seen with the naked eye and can be held • Atomic scale – Nanoscale and molecular scale – Processes cannot be seen 2 1.2 The Properties of Matter All properties of matter are either extensive or intensive. The measured value of an extensive property depends on the amount of matter. Mass is an extensive property. The value of an intensive property are independent on the amount of matter. Density and temperature are intensive properties. 3 Some Chemical Properties of the Elements Physical Properties: Characteristics that do not involve a change in a sample’s chemical makeup. Chemical Properties: Characteristics that do involve a change in a sample’s chemical makeup. Temperature Conversions • Fahrenheit to Celsius 9 T(°F) = T(°C) + 32 5 9 T(°F) = (82.63 °C) + 32 = 180.73 F 5 • Celsius to Kelvin 1K ×  T°C + 273.15°C  1°C 1K = 298.2 K  25.0°C + 273.15°C  × 1°C T(K) = 5 Density Units • Density: Physical property that relates the mass of a substance to its volume mass Density = volume • Densities of solids and liquids are reported: – As grams per milliliter (g/mL) or grams per cubic centimeter (g/cm3) 1 mL = 1 cm3 – At a standard temperature, 25°C, close to room temperature 6 Density Example Determine the mass of 3274 mL of mercury, with a d = 13.55 g/mL. m = V x d = 3274 mL x 13.55 g = 4.436 x 104 g 1 mL Interactive Figure 1.2.5 - Classify Matter Mixture combo of two or more substances retain their distinct identities Substance definite composition & distinct properties Element cannot be separated into simpler substances by chemical means Compound atoms of two or more elements in fixed ratio. Homogeneous uniform throughout Heterogeneous not uniform throughout 8 1.3 1.3 Scientific Measurement SI Base Units Measured property Unit name Abbreviation Mass Kilogram kg Length Meter m Time Second s Temperature Kelvin K Amount Mole mol Electric current Ampere A Luminous intensity Candela cd 9 Units of Measure Metric prefixes are combined with SI units when reporting physical quantities Prefix Abbreviation Meaning Example Giga G 109 (billion) 1 gigahertz = 1 X 109 Hz Mega M 106 (million) 1megaton = 1 X 106 ton Kilo k 103 (thousand) 1 kilometer (km) = 1 X 103 m Deci d 10-1 (tenth) 1 decimeter (dc) = 1 X 10-1 m Centi c 10-2 (onehundredth) 1 centimeter (cm) = 1 X 10-2 m Milli m 10-3 (one thousandth) 1 millimeter (MM)= 1 X 10-3 m Micro m 10-6 (one millionth) 1 micrometer (mm)= 1 X 10-6 m Nano n 10-9 (one billionth) 1 nanometer (nm) 1 X 10-9 m Pico p 10-12 1 picometer (pm) =1 X 10-12 m Femto f 10-15 1 femtometer (fm)= 1 X 10-15 m 10 Scientific Notation • Numbers are expressed in a format that conveys the order of magnitude – General form: N × 10x • Converting standard notation to scientific notation – Count the number of times the decimal point is moved to the right or left 3285 ft = 3.285  103 ft 0.00215kg = 2.15  103 kg 1 Precision and Accuracy • Precision: How close the values in a set of measurements are to one another • Accuracy: How close a measurement or a set of measurements is to a real value 12 1.4 Uncertainty in Measurement Chemistry makes use of two types of numbers: exact and inexact. Exact numbers include numbers with defined values with infinite significant figures, such as 2.54 in the definition 1 inch (in) = 2.54 cm 1000 in the definition 1 kg = 1000 g 12 in the definition 1 dozen = 12 objects. Numbers measured by any method other than counting are inexact. 13 1.4 Uncertainty in Measurement An inexact number must be reported in such a way as to indicate the uncertainty in its value. Significant figures are the meaningful digits in a reported number. 14 Counting Significant Figures Rule Example Number of significant figures 1256 4 All zeros between non-zero numbers are significant-captive zeros 1056007 7 Leading zeros are NEVER significant (zeros to the left of your first non-zero number) 0.000345 3 0.00046909 5 1780 3 770.0 4 0.08040 4 All non-zero numbers are significant Trailing zeros are significant ONLY if a decimal point is part of the number (zeros to the right of your last non-zero number) 1 1.3 Uncertainty in Measurement Significant Figures To avoid ambiguity in such cases, it is best to express such numbers using scientific notation [Appendix 1]. 1.3 × 102 two significant figures 1.30 × 102 three significant figures 50 Rounding Numbers • Find the last digit that is to be kept • Check the number immediately to the right – If that number is less than 5 leave the last digit alone 2.543 round down to 2.54 – If that number is 5 or greater increase the previous digit by one 2.546 round up to 2.55 1 Round to Two Significant Figures Find the last digit that is to be kept Check number to the right Is digit to the right less than 5? Is digit to right 5 or greater? Rounded number 1056007 1056007 No Yes 1100000 0.000345 0.000345 No Yes 0.00035 1740 1740 Yes No 1700 1 1.3 Uncertainty in Measurement Calculations with Measured Numbers Addition and Subtraction, the answer cannot have more digits to the right of the decimal point than the original number with the smallest number of digits to the right of the decimal point If the leftmost digit to be dropped is less than 5, round down. If the leftmost digit to be dropped is equal to or greater than 5, round up. 55 1.3 Uncertainty in Measurement Calculations with Measured Numbers Multiplication and Division, the number of significant figures in the final product or quotient is determined by the original number that has the smallest number of significant figures. 2 SF 4 SF 2 SF 56 1.3 Uncertainty in Measurement Addition and Subtraction with Multiplication and Division, the number of significant figures in the final answer is based on the Order of Operations and the corresponding rule needed. 2.54 cm x (147.9 inch – 145.900 inch) = ?? inch Do () math 1st: 147.9 inch – 145.900 inch 2 SF 2.000 inch ~ 2.0 inch 3 SF 2 SF 3 SF 2 SF Then multiply: 2.54 cm x (2.0 inch) = 5.08 cm ~ 5.1 cm inch 56 1.3 Using Units and Solving Problems A conversion factor is a fraction in which the same quantity is expressed one way in the numerator and another way in the denominator. Both forms of this conversion factor are equal to 1, we can multiply a quantity by either form without changing the value of that quantity. 72 Dimensional Analysis Useful US units to Metric Unit Conversions • 1 in = 2.54 cm • 1 lb = 453.6 g • 1 oz (mass) = 28.3459231 g (mass) • 1 oz (fluid) = 29.5735 mL (fluid) FOLLOW THE UNITS! 2 Example of Conversion Factors • Conversion factors - Used to make the conversion between units – The resulting quantity is equivalent to the original quantity, it differs only by the units Unit (1) ×conversion factor = unit (2) – Example - Metric to metric equalities 1 m = 100 cm 1m 102 cm or 2 10 cm 1m • Use of exact conversion factors will not affect the significant figures in a calculation 24 1.6 Using Units and Solving Problems The use of conversion factors in problem solving is called dimensional analysis or the factor-label method. A proportionality (or conversion) factor was used. known units x desired units = desired units known units FOLLOW THE UNITS! Make sure UNITS Cancel Out before doing the math! 74 1.6 Using Units and Solving Problems The speed of light in a vacuum is 2.998 x 108 m/s, what is the speed in cm/min? 2.998 x 108 m x 100 cm x 60 s = 1.799 x 1012 cm s 1m 1 min min FOLLOW THE UNITS! Make sure UNITS Cancel Out before doing the math! 74 Exercise: How Many Picometers Are in 25.4 nm? Given: 25.4 nm Find: pm Roadmap: Factors: Solve: nm m  pm 1 m 1012 pm ; 9 10 nm 1 m 1m 1012 pm 25.4nm × 9 × = 2.54 ×10 4 pm 10 nm 1m FOLLOW THE UNITS! Make sure UNITS Cancel Out before doing the math! Check: We would expect a greater number of pm and that is what we have 27

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Prof_Holley
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Reading an article
Three concepts from within the article and relate them to 3 concepts within CHEM 210
1. The first concept that I learned from the article is that of mixtures. From the textbook, a
mixture is a combination of two o...

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Anonymous
Tutor went the extra mile to help me with this essay. Citations were a bit shaky but I appreciated how well he handled APA styles and how ok he was to change them even though I didnt specify. Got a B+ which is believable and acceptable.

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