==2004-2005 P.O.D.s== ==GSLG== Q. Izzy earns 16 out of 20 possible points on a science quiz. What is her grade, expressed as both a percentage and a letter grade? A. 16/20 x 100 = 80% or C+ ==Science Process Skills== Q. Nia notices Mr. Sanford's right eye is red and asks, "Do you have allergies?" Identify Nia's observation(s) and inference(s). A. Observation: Right eye red. Inference: Redness caused by allergies. Is this a fact? No. The redness could be caused by rubbing my eye, or grapefruit juice in my eye. Note that other causes of red-eye (e.g., lack-o sleep) usually affect BOTH eyes! [Provisioning: Wear an item of college/university-related merchandise.] Q. Where did Mr. Sanford graduate from college? A. Lead post-POD discussion re: observation & inference. Observation(s): Mr. Sanford is wearing a/an [x item] from [x name] college/university (c/u). Inference(s): Mr. Sanford graduated from [x name] college/university. Note: It is certainly possible Mr. Sanford attended [x name] c/u w/o graduating, or visited [x name] c/u, or simply purchased an item of merchandise w/o ever visiting &/or attending the c/u. -- [Bi-POD] Q. 1 L = ? ml A. 1,000 ml Q. 35.6 ml of H2O = ? kg A. 35.6 ml of HOH = 35.6 g of HOH, or .0356 kg -- [Bi-POD] Q. Mr. Sanford got a hair cut. True or False. A. False, he got ALL of his hairs cut! Q. 250 ml of H2O = ? kg A. 250 g of H2O = .250 kg -- Q. A construction contractor ordered a wooden beam 10 m long from a building supply store. The building supplier delivered a beam 20 m long; subsequently, the contractor returned the beam to the supplier. Why? A. It's 2 dam long! -- [Use near date of SEP Equinox.] Q. Show Earthdial image from SEP Equinox and say something like (while pointing), "On the day of the SEP Equinox, the subsolar point crossed the Equator; from that day forward, the subsolar point is moving toward the Tropic of Capricorn." What's wrong with this picture? A. Students may point out the difference between Solar Time and Standard Time (due to Daylight Saving Time), but the point of the question is to realize that the Tropics of Cancer & Capricorn are reversed on the sundial face compared to a globe of the Earth. ==GSLG== Chemi-PODs [Bi-POD] Q. What is the density of H2O? A. By definition, 1 g/cc. Q. An object sinks in H2O. What can you infer about the density of the object relative to the density of water? A. The object is more dense than water. -- [Honors] Q. A graph of mass versus density results in a straight-line graph. What does this mean? (Need a better wording of question.) A. The relationship between mass & volume is constant, that is, density IS a characteristic property! -- Q. The following objects are immersed in water. What should you observe? A) Lead B) Balsa wood C) Ice A. Lead sinks, ice floats, and balsa floats higher. -- [Honors] Q. If the speed of light is 186,000 mi/sec, then how far will light travel in one year (mi/yr)? [re: dimensional analysis] A. 186,000 mi/sec x 60 sec/min x 60 min/hr x 24 hr/day x 365 days/yr = ~6 trillion mi/yr -- Q. Water spills out of a graduated cylinder when measuring the volume of an unknown sample. How will this affect both your measurement of volume and calculation of density? A. The measured volume would be lower; the calculated density would be higher. -- Q. A cube 30 mm on a side has a mass of 100g. What is its density? A. Volume = 27cc; D = 100g / 27cc = 3.704 g/cc -- 19 OCT 2004 Q. When a solute dissolves in a solvent, does a chemical- or physical change occur? A. A physical change. -- 28 OCT 2004 Q. In the following solutions, identify the solute and solvent: - Solution of 400g CuSO4 and 1000 ml of H2O A. CuSO4 = solute; H2o = solvent. - 1:3 solution of ammonia and water A. Ammonia = solute; water = solvent. Q. Refer to the graph on p. 23, Green Lab Manual. 40g of KNO3 is added to 100ml of H2O at 60dC -- is the resulting solution saturated or unsaturated? A. Unsaturated. At 60dC, it takes ~81g of KNO3 to saturate 100ml of H2O. -- 04 NOV 2004 Q. Chef Sanford heats a pot of water to cook pasta. After several minutes, bubbles begin to form in the pot of water. Is this evidence of a chemical or physical change? A. Physical change. When water boils, it simply changes from one phase (or state of matter) to another. -- 10 NOV 2004 H-I-J-K-L-M-N-O Q. What is the preceding substance? A. H-to-O -- 11 NOV 2004 Q. Any of two or more kinds of atoms of the same element having the Atomic No. but differing Atomic Masses is called... a) Isotoner b) Isoconfused! c) Imadope d) Isotope A. Isotope ==2005-2006 P.O.D.s== ==GSLG== == GSLG ---- 21 OCT 2005 Atomic PODs: [show graphic of box from Periodic Table for Potassium] Q. What is the name of this element? A. K Q. How many neutrons are in the nucleus? A. 20 Q. How many electrons are in an atom of this element? A. 19 -- 24 OCT 2005 Periodic PODs: Q. Which element has 16 protons in its nucleus? A. Sulfur Q. In which period and group is Al? A. Period 3; Group 13 Q. How many electron enrgy levels are in an atom of potassium? A. four (4) -- 25 OCT 2005 Q. How many neutrons are in an atom of Ti? A. 6 Q. Draw a Bohr model of a Boron atom. Boron! A. Nucleus: 5(+),6(=); Electron "cloud": 5(-) -- 26-27 OCT 2005 Q. How many neutrons are in an atom of Ar? A. 22 Q. How many neutrons are in an atom of C-14? A. 8 (rather than 6) -- 28 OCT 2005 Q. List the protons, neutrons, and electrons for an isotope of Carbon, e.g., C-14. A. 6 P, 8 N, 6 E Q. Draw a Bohr model of a Na atom. A. 11 P, 12 N, 11 E Q. List the P,N,E for a Na ion. A. 11 P, 12 N, 10 E -- 03 NOV 2005 Q. List at least two ways elements are arranged on the Periodic Table. A. increasing Atomic Number; by period & group; same no. outer electrons/similar properties -- 15 NOV 2005 Reacto-POD Q. List at least two (2) clues that a chemical change may have occurred. A. temperature change (endo-, exo-); color change; gas production; precipitate formation -- 16 NOV 2005 Reacto-POD Q. Mr. Sanford buys a "hot pack" for his aching back. The pack is the kind you put in a microwave oven. What causes the pack to get to get hot -- a chemical- or physical change? A. Physical change -- 18 NOV 2005 1st Per. Q. Count the number of atoms of each element in one molecule of NaHCO3. A. (1) Na; (1) H; (1) C; (3) O 2nd-3rd Per. Q. Are you "actively participating in class" if the teacher must prompt you to pay attention and do your work? A. No! -- 29 NOV 2005 [Note: These PODs follow on the "Old Foamey" demo/graph.] 2nd-3rd Per. Q. A student collects time and temperature data. Which data set is the dependent variable? A. Temperature. [These data depend upon the outcome of the experiment.] Q. Which data set should go on the "X" axis of a graph? Explain. A. Time. By convention, the independent variable usually goes on the x-axis. -- 05 DEC 2005 Q. What is the name of the following substance? H-I-J-K-L-M-N-O A. H to O -- 14 DEC 2005 Q. The pH scale, numbered from 0-14, is logarithmic. A pH of 2 is how many times stronger than 5? A. 10 x 10 x 10 = 1,000x -- 04-05 JAN 2006 [re: lab activity, "Disappearing Powder - Investigating Solubility, Part 1: Creating and Interpretting Solubility Graphs," pp. 97-104] Q. If you were given a medicine cup filled with a "mystery powder," then what information would you need to know in order to determine how much of the powder was used during the experiment? A1. To find the initial mass of the powder, subtract the mass of the empty med. cup from the mass of the med. cup plus the powder. A2. To find the final mass of the powder, subtract the mass of the empty med. cup from the mass of the left-over powder. A3. To find the mass of powder used during the experiment, subtract the mass of the left-over powder from the initial mass of the powder. -- 06 JAN 2006 Q. For the following sets of numbers, what is the MEDIAN? Note: MEAN = average; MODE = most frequent no. A) 10, 2, 8, 5, 3 B) 7, 9, 1, 5, 11, 6 First, arrange the numbers in SERIES from smallest to largest: A) 2, 3, 5, 8, 10 B) 1, 5, 6, 7, 9, 11 The MEDIAN is the middle number: A) 5 B) 6.5 [MEAN (avg.) of the two middle numbers] -- 09 JAN 2006 Q. What is an ordered pair of numbers? A. ordered pair: Set of two numbers in which the order has an agreed-upon meaning, such as the Cartesian coordinates (x, y), where the first coordinate represents the horizontal position, and the second coordinate represents the vertical position. -- 10 JAN 2006 Q. [re: solubilty graph of KNO3] At the point(s) shown on the graph, would the solution be unsaturated or saturated? A. Answer varies: Point above the line, saturated; below the line, unsaturated. Calculate amount of surplus, or amount of deficit. -- 11-12 JAN 2006 Q. At a temperature of 60C, what is the mass of KNO3 required to saturate 100ml of water? (Refer to your "Gizmo" graph of Solubility and Temperature.) A. ~110g -- 13 JAN 2006 Q. In the following solutions, identify the solute and solvent: - Solution of 400g CuSO4 and 1000 ml of H2O A. CuSO4 = solute; H2O = solvent. - 1:3 solution of ammonia and water A. Ammonia = solute; water = solvent. -- 17 JAN 2006 Q. Refer to the graph on p. 103, Green Student Lab Guide. 40g of KNO3 is added to 100ml of H2O at 60dC -- is the resulting solution saturated or unsaturated? A. Unsaturated. At 60dC, it takes ~110g of KNO3 to saturate 100ml of H2O. -- 18 JAN 2006 Q. When a solute dissolves in a solvent, does a chemical- or physical change occur? A. A physical change. ==2006-2007 P.O.D.s== ==GSLG== 08 SEP 2006 Q. Mr. Sanford graduated from JMU. True or false? A. True. -- 11 SEP 2006 Q. All billiard balls are striped. True or false? If you ignored the cue ball, then would your answer be different? A. True. The stripes are wider on the "solid"-colored balls. -- 13-14 SEP 2006 (Per. 1,3 only) Q. What _observation(s)_ can you make that would lead you to _infer_ that we will use computers in class today? A. PC mobile lab; teacher's laptop + LCD projector Q. Which metric unit of _length_ is 10x >1 meter? A. 1 dekameter (dam) -- 15 SEP 2006 Q. A milliliter (mL) is what fraction of a liter (L)? A. 1/1000 Q. How many mL = 1 centiliter (cL)? A. 10 mL -- 19 SEP 2006 Q. What is the density of water? A. 1 g/cc Q. A cube measuring 2 cm on a side has a mass of 16 g. What is its density? A. V = 2cm x 2cm x 2cm; V = 8cc D = 16g / 8 cc = 2 g/cc -- 20 SEP 2006 (Honors) Q. 35.6 mL of H2O = ? kg A. 35.6 mL of HOH = 35.6 g of HOH, or .0356 kg Q. A _characteristic property_ is like a __?__. How are CPs useful? A. _fingerprint_. CPs may be used to infer the identity of unknown substances. [Note: A simile is a comparison using "as" or "like."] -- 21 SEP 2006 (Per. 1&3) Q. A _characteristic property_ is like a __?__. How are CPs useful? A. _fingerprint_. CPs may be used to infer the identity of unknown substances. Q. What is the _density_ of an unknown substance with a mass of 25g and a volume of 3 mL? Q. D = M/V; 3mL = 3cc; D = 25g/3cc; D = 8.3g/cc -- 22 SEP 2006 Q. 1 L = ? mL A. 1,000 mL Q. A cube 30mm on a side has a mass of 100g. What is its density? A. 30mm = 3.0cm; Volume = 27cc; D = 100g / 27cc = 3.704 g/cc -- 25 SEP 2006 Q. Three samples of the same substance have the following masses & volumes: Sample A) 5g, 2cc; Sample B) 20g, 8cc; Sample C) 30g, 12cc. What can you conclude about the density of the three samples? Support your answer with data. A. All three samples have the same density (2.5g/cc), regardless of their size and shape. Note: The ratio of mass and volume is always the same -- the mass is 2.5x bigger than the volume. -- 26 SEP 2006 Q. An object sinks in H2O. What can you infer about the density of the object relative to the density of water? A. The object is more dense than water. Q. In terms of density, explain the difference in the observed behavior of the two 12 oz. sodas. [Coke Classic & Diet Coke] A. Difference in density caused by ingredients: high fructose corn syrup vs. aspartame (NutraSweet) 12 oz. cans: 39 g of sugar; 100 mg of NutraSweet Google Search: how much sugar in a 12 oz. coke? http://www.middleschoolscience.com/dietcoke.htm http://www.nutrasweet.com/ -- 27-28 SEP 2006 [All classes (Per. 1-3)] Demo-P.O.D.s: Q. "Coke Classic" can immersed in H20 revisited. Explain why the can floats. A. The liquid in which the soda can is immersed must be more dense than water. The "aquarium" contains saltwater; D = ~1.03 g/cc. Q. "Rainbow" Column of Liquids - Assuming the graduated cylinder contains three different liquids, explain your observations in terms of density. Which layer is most dense? Least dense? A. The most dense liquid is the bottom layer in the graduated cylinder; the least dense liquid is the top layer. [Honors only] Q. A graph of mass versus density results in a straight-line graph. What does the linear relationship between mass and volume tell you about density? (I think this is a better wording of the question than '05-06.) A. For a given substance, the mathematical relationship (ratio) between mass & volume is constant, therefore, density IS a characteristic property! Q. Water spills out of a graduated cylinder when measuring the volume of an unknown sample. How will this affect both your measurement of volume and calculation of density? A. The measured volume would be lower; the calculated density would be higher. -- 20 OCT 2006 [Note: The following POD should be timed to precede the due date for the TAP foldable-poster, in order to ensure students have drawn the model correctly.] Q. Draw an "electron cloud model" of _your_ TAP element. A. (answers will vary) -- 23 OCT 2006 Q. Draw an electron cloud model for Argon (Ar). (Per. 1 & 3) -- 26 OCT 2006 Q. Draw an "electron cloud model" for Sulfur (S). (Per. 1 & 3) -- 27 OCT 2006 Q. Referring to the Periodic Table of the Elements, what is a "period?" "Group?" A. period = row; group = column Q. What is the meaning of the word "periodic?" A. recurring at regular intervals [a repeating pattern] -- 01-02 NOV 2006 IsotoPODs (Isotope PODs): Excerpt from SOL Review Booklet re: radiometric dating using carbon-14, including four (4) questions. http://www.wsanford.com/~wsanford/gr8ps/01_green/04_invisible_atom/extras/ carbon-dating/PODs_radiometric-dating.doc <-- enter URL on one line == [fill in gap] == -- 15-16 NOV 2006 Q. What is an exothermal reaction? Give an example of one. A. A chemical reaction in which thermal energy (heat) is released. -- 20 NOV 2006 Q. 250 g of CuSO4 is dissolved in one (1) liter of H2O. Is this an example of a physical change or a chemical change? A. Physical change. [Note: Add small amount of CuSO4 solution to a 250ml beaker; let the solution evaporate. Observe crystal formation.] -- 04 DEC 2006 Q. Are the following chemical equations balanced or unbalanced? If not, then try to balance the equation(s). (endothermic) ^ H3C6H5O7(aq) + 3NaHCO3(s) --> 3H2O(l) + Na3C6H5O7(aq) + 3CO2(g)| citric acid + sodium bicarbonate (baking soda) --> water + sodium citrate (salt solution) + carbon dioxide gas A. Yes, equation IS balanced. H 11 C 09 O 16 Na 03 (exothermic) Mg(s) + HCl(aq) --> MgCl2(aq) + H2(g) magnesium (solid metal) + hydrochloric acid --> magnesium chloride (salt solution) + hydrogen gas [Note: MgCl2 is commonly used as a deicer. Recover product (solution); allow water to evaporate. Test MgCl2(s) salt on water ice to see if it will melt ice.] A. No, equation IS NOT balanced. R | P Mg 1 | Mg 1 H 1 | H 2 Cl 1 | Cl 2 ^ Mg(s) + 2HCl(aq) --> MgCl2(aq) + H2(g)| R | P Mg 1 | Mg 1 H 2 | H 2 Cl 2 | Cl 2 ***Teacher's Note: Revisit the endothermic reaction [citric ACID + sodium bicarbonate (BASE) --> water + sodium citrate (salt solution), which is also a neutralization reaction (acid + base --> water + salt). Segue to "Colorful Chemical Clues" lab activity.*** mnemonic: solution = solute-ION -- 06-07 DEC 2006 Reacto-POD Q. Mr. Sanford buys a "hot pack" for his aching back. The pack is the kind you put in a microwave oven. What causes the pack to get to get hot -- a chemical- or physical change? A. Physical change -- 08 DEC 2006 Q. The pH scale, numbered from 0-14, is logarithmic. A pH of 2 is how many times stronger than 5? A. 10 x 10 x 10 = 1,000x stronger Q. What is the name of the following substance? H-I-J-K-L-M-N-O Hint: It is one of the products of a neutralization reaction. A. H-to-O -- 02 JAN 2007 Q. What is "hydrogen hydroxide?" A. Water!