Introduction to Chemistry (Chemistry for Engineers).pptx

This is a module for the Chemistry for Engineers.

1. What is Chemistry?

2. Chemistry is the study of composition, structure, and properties of matter and the changes it undergoes.

3. Importance of Chemistry in the Field of Engineering: Engineering Materials Energy Sources The role of chemistry in saving the environment

4. Matter is anything that occupies space and has mass. States of Matter: 1. 2. 3.

5. Matter is anything that occupies space and has mass. States of Matter: 4. Plasma is an ionized gas. 5. Bose-Einstein Condensate occurs at ultralow temperature (very near absolute zero), close to the point that the atoms are not moving at all.

6. Classification of Matter Matter Mixtures Pure Substances Homogeneous Mixtures Heterogeneous Mixtures Compounds Elements Separation by Chemical methods Separation by Physical methods

7. Classification of Matter Any mixture components can be separated by physical means.

8. Properties of Matter Physical Properties are properties which can be measured without changing the identity and composition of a substance. Physical changes are those changes that do not result in the production of a new substance. Chemical properties are properties that lead to changes in the identity and composition of a substance.

9. Properties of Matter Chemical change or chemical reactions are changes that result in the production of another substance. Extensive property is those that do depend of the size of the sample involved. Intensive property is those which do not depend on the size of the sample involved.

10. Measurements Quantity SI unit Length meter(m) Mass kilogram(kg) Time Seconds (s) Temperature Kelvin (K) Electric current ampere (A) Amount of substance mole (mol) Luminous intensity Candela (cd) Fundamental quantities and their SI unites

11. Measurements Prefixes for powers of Ten Factor Prefix Symbol Factor Prefix Symbol 10 24 yotta Y 10 -1 deci d 10 21 zetta Z 10 -2 centi c 10 18 exa E 10 -3 milli m 10 15 peta P 10 -6 micro µ 10 12 tera T 10 -9 nano n 10 9 giga G 10 -12 pico p 10 6 mega M 10 -15 femto f 10 3 kilo K 10 -18 atto a 10 2 hecto h 10 -21 zepto z 10 1 deca da 10 -24 yocto y

12. Significant Figures The digits that carry meaning in a number and contribute to its precision. The number of significant figures is related to the numerical digits used to express the measurement. Any digit that is not zero is significant. Ex: 156 m – 3 significant figures Zeroes between nonzero digits are significant. Ex: 406 cm – 3 significant figures Zeros to the left of the first nonzero digit are not significant. Ex: 0.0000 1 m – 1 significant figures

13. Significant Figures The digits that carry meaning in a number and contribute to its precision. The number of significant figures is related to the numerical digits used to express the measurement. If a number is greater than 1, then all zeros to the right of the decimal point are significant. Ex: 3 . g, - 2 significant figures If a number is less than 1, then only the zeros that are at the end and in the middle of the number are significant. Ex: 0.0 440 – 3 significant figures

14. Rules of Significant figures in Calculations The number of decimal places in the result should equal the smallest number of decimal places of any term in the sum or difference. The number of significant figures in the final answer is the same as the number of significant figures in the quantity having the smallest number of significant figure. Example: 89.332 + 1.1 = 90.432 → 90.4 3.70 – 2.9133 = 0.7867 → 0.79 Example: 4.51x3.6666 = 16.536366 → 16.5 6.8 ÷ 112.04 = 0.0606926 → 0.061 Addition/Subtraction Multiplication/Division

15. Accuracy Precision Accuracy how close a measurement is to the true value. Precision how close a set of measurements are to each other. Length Mass Volume 1 m 100cm 1 kg 1000 g 1 mL 1 cm 3 1 in 2.54cm 1 kg 2.21 lb. 1 L 1000mL 1 m 3.28 ft. 1 ton 2000 lb. 1 m 3 1000L 1 mi 5280 ft. 1 metric ton 1000 kg 1 ft. 12 in 1 slug 14.59 kg

16. Temperature Conversion ° C = (°F – 32 ) °F = °C + 32 K = °C + 273 R = °F + 460   LEGEND: °C – °Celsius °F – °Fahrenheit K – °Kelvin R - ° Rankine

17. Some Derived Units Area – Products of two lengths (m 2 ) Volume – the amount of space that a substance or object occupies (m 3 ) Speed – ratio of distance travel to a time interval (m/s) Density – the mass of a substance per unit volume(kg/m 3 ) ppm or parts per million – tells how many particular substances are present for every 1000000 particles in the sample. Force (1 N = 1 ) Pressure – force per unit area (1 Pa = ) Energy (1 J = 1 N – m) Power ( 1 W = 1 J/s)  

18. Dimensional Analysis Method of Solving Problems Determine which unit conversion factor(s) are needed. Carry units through calculation. If all units cancel except for the desired unit(s), then the problem was solved correctly. Given unit x conversion factor = desired unit Examples: Convert the following : a. 0.0833 lb. to mg. d. 105°F to K b. 275 L to m 3 e. 8.314 to c. 0.808g/cm 3 to kg/m 3 f. 2 hp to  

19. 2. Titanium is used in airplane bodies because it is strong and light. It has a density of 4.55g/cm 3 . If a cylinder of Titanium is 7.75cm long and has a mass of 153.2g. Calculate the diameter of the cylinder.

20. 3. Magnesium is a valuable metal used in alloys, in batteries, and in synthesis. It is obtained mostly from seawater , which contains about 1.3g of Magnesium for every kilogram of seawater. Calculate the volume of seawater (in Liters) needed to extract 8 x 10 4 tons of Magnesium which is roughly the annual production in United States. (Density of seawater is 1.03g/mL)

21. 4. At what temperature does numerical reading on a Celsius thermometer equal on a Fahrenheit thermometer?

22. 5. The Chlorine is used to disinfect swimming pools. The accepted concentration for this purpose is 1 ppm chlorine or 1g of chlorine per million gram of water. Calculate the volume of a chlorine solution (in mL) a home owner should add to her swimming pool if the solution contains 6% chlorine by mass and there are 2 x 10 4 gallons of water in the pool. (1 gallon = 3.79L and density of water is 1 g/mL and density of solution is 1 g/mL)