Name: KEY Period: 1. Know all vocabulary definitions. 2. Name 4 chemical properties & 4 physical properties of matter.

Transcription

1 Name: KEY Period: Chapter 4 The Properties of Matter and the Analysis of Glass Review 1. Know all vocabulary definitions. 2. Name 4 chemical properties & 4 physical properties of matter. Chemical: burning, rusting, decomposing, and color change Physical: weight, volume, color, boiling & melting point 3. Name 4 types of chemical reactions and give ABCD diagram for each. Synthesis : A + B à AB Single Replacement: AB + C à CB + A Decomposition: AB à A + B Double Replacenent: AB + CD à AD + BC *PPT has Single Replacement as AB + C à AC + B and Double Replacement as AB + CD à AC + BD; technically these are incorrect. 4. Name the 3 basic units of measurement for length, mass, and volume in the metric system. Length = meter Mass = gram Volume = liter 5. What is the relationship between cm 3, cc, and ml for liquids in the metric system? 1cm 3 = 1cc = 1 ml 6. Be able to perform metric conversions using King Henry and the Ladder Method (or method of your choice). a km = 657,000,000 mm or 6.75 x 10 6 mm b dg (decigrams) = Dg (dekagrams) 7. Be able to perform conversions using the Factor Label Method (Dimensional Analysis). a. Know how many centimeters are in 1 inch: 2.54 cm = 1 inch b. How many days are in 555,555 seconds? 555,555 s 1 min 1 hr 1 day = days 60 s 60 min 24 hr c. How many centimeters are in 3545 feet? 3545 ft 12 in 2.54 cm = 108,051.6 ~ 108,100 cm 1 ft 1 in 8. Compare attractive forces and density in the three state of matter. a. Which state has the strongest attractive forces between molecules? solid b. Which state has the weakest attractive forces between molecules? gas c. Which state is generally considered the most dense (higher density)? solid d. Which state is generally considered the least dense (lower density)? gas e. Which state has no specific shape and no specific volume? gas f. Which state has a specific shape and a specific volume? solid g. Which state takes the shape of its container and has a specific volume? liquid 1

2 9. Describe the two models of the behavior of light. Light behaves as a continuous wave and as a stream of discrete energy particles known as photons. 10. As electromagnetic radiation moves through space, its behavior can be described as that of a continuous wave. 11. Once radiation is absorbed by a substance, it is best described as discrete particles of light known as photons. 12. Understand how the frequency, wavelength, and energy of light are related. a. Draw a wave that has high frequency. b. Draw a wave that has low frequency. c. Referring to your diagrams above, high frequency means that the wavelength is always (shorter or longer) than low frequency waves. d. The higher the frequency, the (higher or lower) the energy of the wave. 13. What is the difference between the electromagnetic spectrum and the visible spectrum? The electromagnetic spectrum is the entire range of radiation in the universe; whereas, the visible spectrum is only a small part of radiation within the larger electromagnetic spectrum. In addition, the visible spectrum is the only part of the larger spectrum that we can actually see. 14. List the radiation types in order from the most dangerous (highest energy/highest frequency/shortest wavelength) to least dangerous (lowest energy/lowest frequency/longest wavelength). Gamma rays, X- rays, Ultraviolet, Visible Light, Infrared, Microwaves, Radiowaves 15. List the colors of the visible spectrum in order from highest energy/highest frequency/shortest wavelength to the lowest energy/lowest frequency/longest wavelength. Violet, Indigo, Blue, Green, Yellow, Orange, Red 2

3 16. The most commonly used temperature scale in science is the Celsius scale. a. Celsius scale freezing point of water = 0 C ; boiling point = 100 C. b. Fahrenheit scale freezing point of water = 32 F ; boiling point = 212 F. 17. What is the difference between mass and weight? Mass is the amount of matter an object contains and does not take gravity into consideration. Weight is the force with which gravity attracts a body. a. What is the mass of a 7000 kg elephant on the Jupiter? The elephant s mass on Jupiter is still 7000 kg because mass is independent of gravity anywhere in the universe. 18. A 0.39 g glass fragment is placed in a test tube containing 5.0 ml of water. Once in the test tube, the water level rises to a volume of 7.0 ml. What is the density of the glass fragment? D = m 0.39 g = 0.39 g = g ~ 0.20 g V (7 ml 5 ml) 2 ml ml ml 19. Generally speaking, how does temperature affect the density of a substance? As temperature increases of the substance, the density decreases. a. Which is more dense, a substance at 100F or at 40F? 40 F 20. Why do light waves bend when traveling from one medium such as air into another medium such as water? Light waves travel in air at a constant velocity until they penetrate another medium at which point the waves are suddenly slowed, causing the rays to bend. 21. What is the difference between refraction and refractive index? Refraction is the bending of light waves because of a change in velocity as it penetrates another medium. Refractive index (RI) is the ratio of the velocity of light in a vacuum (air) to the velocity of light in the medium. 22. What two factors can cause refractive index to vary? Both temperature changes and wavelength changes can cause refractive index to vary. 23. How does a crystalline solid like calcite refract a beam of light? Crystalline solids refract a beam of light in two different light- ray components. a. What does this refraction result in? It results in a double refraction and a dual image. b. What does birefringence have to do with your answer in a. Birefringence is the numerical difference between the two refractive indices of the double refraction that occurs. c. What kind of a solid is glass considered? Glass is a noncrystalline solid called an amorphous solid. 3

4 d. Does glass exhibit birefringence? No. Only crystalline solids exhibit double refraction and have birefringence. 24. Describe 5 characteristics of glass in general: Hard, brittle, amorphous substance, mostly sand, and mixed with various metal oxides. 25. What is in soda- lime glass? Soda is added to make it more workable and lime added to make it less dissolvable in water. a. Give 2 examples of this glass: windows and bottles 26. What is in borosilicate glass? Boron oxide added to withstand high heat. a. Give 2 examples of this glass: test tubes and headlights 27. How is tempered glass made? It is made by rapid heating and cooling, repeatedly. a. How does tempered glass break? Tempered auto windows break into small square- like pieces without sharp edges. Pyrex tempered cookware breaks into 1-2 large pieces instead of numerous very sharp pieces. b. Give 3 example of this glass: shower doors, side & rear auto windows, pyrex cookware 28. How is laminated glass made? It is made by placing a plastic film between two pieces of glass. a. Give an example: windshields 29. What are the two most important physical properties used to identify and compare glass fragments? Refractive index and density a. These two physical properties ( ARE or ARE NOT ) considered intensive physical properties. 30. What is the Flotation Method used for? It is used to determine and compare the densities of glass. a. When the standard/reference sample of glass is suspended in the liquid medium, what does this say about their densities? The standard/reference sample and liquid medium have the same/similiar density. b. If the evidence sample of glass is now added to the liquid medium and it also is suspended, what does this say? The evidence sample, standard/reference sample, and the liquid medium all have the same/similar density; therefore, the evidence is the same kind of glass as the standard/reference glass sample. c. And if the evidence sample floats on top of the liquid medium? The evidence sample is less dense than the liquid medium and therefore not the same density as the standard/reference sample and not the same kind of glass. d. And if the evidence sample sinks to the bottom? It is more dense than the medium and not the same density or kind of glass. 4

5 31. What is the Immersion Method used for? It is used to determine the refractive index (RI) of a glass fragment. a. When the evidence sample is immersed in the liquid oil medium and the Becke Line around the sample disappears, what does this say about their refractive indices? The evidence and the liquid oil have the same RI. Since the RI of the liquid will be known, we now know the RI of the glass. b. And if the Becke Line is inside the border of the sample? The RI of the glass is higher than the RI of the liquid. c. And if the Becke Line is outside the border of the sample? The RI of the liquid is higher than the RI of the glass. *ALWAYS REMEMBER: Line inside glass = glass RI is higher : Line outside glass = medium (liquid oil) RI is higher d. What is the benefit of using the GRIM- 3 for RI determination? The analyst can view a large image of the glass fragment to see the Becke line disappear, and the computer automatically adjusts the temperature of the oil and calculates the precise RI at the match point. 32. What is the difference between the radial and the concentric cracks? Radial cracks radiate out from the center of impact like spokes on a wheel. Concentric cracks form circles around the center of the impact. a. Which cracks form first? Radial b. On what side of the glass do they form? Reverse (opposite) side of the impact force c. Which cracks form second? Concentric d. On what side of the glass do they form? On the same side as the impact force e. What is the 3R Rule used for? Used to determine the direction of impact force on glass f. State the 3R Rule: Radial cracks form a Right angle on the Reverse side of the force. g. The term right angle means ( PERPENDICULAR or PARALLEL ). h. What happens on the concentric edges of glass? Concentric cracks form a right angle on the same side of the force. i. Apply the 3R Rule and draw the correct fracture pattern on the radial edge and on the concentric edges of glass fragments: Concentric Radial Impact Force Impact Force 5

6 33. When given multiple gunshot penetrations, how do you determine which shot was first? Fractures from the first impact act as barriers stopping fractures from the second impact. Look for radial fracture lines that abruptly stop when coming in contact with radial fractures from the first impact. 34. Which side ( ENTRANCE or EXIT ) of the glass will a high- velocity projectile, such as a bullet or bb gun pellet, leave a wider hole? 35. What is the only way to link two glass fragments to a common source? By physically matching the evidence glass to the broken glass from the crime scene like a puzzle. 36. If there is a possibility that glass fragments can be pieced together for an individual fit, how should the glass be collected? All the glass found at the scene and all the glass from the suspect needs to be collected. 37. If an individual fit is not possible, what glass should be collected? A representative sample of broken glass from the scene and all the glass from the suspect needs to be collected. 38. What containers are best suited for collection of glass? Packaged in solid containers to avoid further breakage. 39. If a suspect s shoes and/or clothing is to be collected for glass fragments, how should it be packaged? The shoes should be individually wrapped in paper and the clothing in different paper. 6