1. chemistry

    A light green powder is heated in a test tube. A gas is given off, while the solid becomes black. In which classification of matter does the green powder belong? Explain your reasoning.
  2. science

    A light green powder is heated in a test tube. A gas is given off and the solid becomes black. In which classification of matter does the green powder belong? Explain your reasoning.
  3. chemistry

    Q: I just did an online chemisty lab for Oxidation States of Manganese and I'm stuck. I have three test tubes that have been prepared as follows: Tube 1- Starting PH 13.82 2 mL of KMnO4 1 mL of NaOH Tube 2- Starting PH 7 2 mL of KMnO4 Tube 3- Starting PH 0
  4. Science

    Suppose that you heated a sample of a hydrated ionic compound in a test tube. What might you expect to see inside the test tube, near the top of the test tube? Explain please i really am stumped on this question...
  5. Chem 100 Lab

    A black solid is heated in a tube that is completely evacuated of air. Hydrogen is added to the tube. An orange powder is formed and water vapor is seen on the outside of the tube. Is the original solid an element or compound? Can you identify the
  6. Chemistry

    If I heated NaNO3, would there be yellow gas inside the test tube?
  7. Chemistry

    1. Tube # 3: (a) It started out as purple, and turned into green. (b) No precipitate was noticably formed. Tube #4: (a) This tube was purple, and turned into white. (b) A brown precipitate was formed after adding 1 mL of NaHSO3. Tube #5: (a) This tube was
  8. Chemistry

    Reaction 6 1. Place a piece of mossy zinc in a test tube 2 add hydrochloric acid solution to the test tube until the mossy zinc is completely covered What gas was released in reaction 6 and how could you test the gas to confirm its identity?
  9. Chemistry

    I need to determine the "percentage composition unknown" whatever that is. My current data: a) mass of test tube and foil cover: 7.5323 g b)temp of water bath: 375.65 K c) mass of test tube and foil and gas as sample: 7.5423 g d) barometric pressure:
  10. Chemistry

    Joseph Priestly discovered oxygen when he heated a red powder. This red powder had been prepared by heating mercury in air. a) name th red powder formed when this element is heated in air b) write a word equation to show what happens to this red powder
  11. Chem

    A gas generator is constructed to collect the CO2(g) evolved from a reaction. during lab we set up the CO2 generator by placing 10ml of 3 M HCL in a 200mm test tube. then slide the 75mm test tube into the 200mm test tube without splashing any of the acid
  12. chem

    a test tube containing CaCo3 is heated until all the compound decomposes. If the test tube plus calcium carbonate originally weighed 30.08 grams and the loss of mass during the experiment is 4.40 grams, what was the mass of the empty test tube? Write the
  13. BIOLOGY LAB!

    If catalase enzyme was placed in a test tube and heated to 100 degrees C, what results would you expect from a glowing splint test? Thanks! Thanks! Thanks!
  14. biology

    If catalase enzyme was placed in a test tube and heated to 100 degrees what results would you expect from a glowing splint test?
  15. Chemistry

    You have 20mL of a solution of concentration 0.015mg/mL of x in test tube #1. Prepare serial dilutions of your stock solution, and calculated the concentration of x as follows: Add 10mL of distilled water and 10mL of stock solution from test tube 1 to test
  16. Chemistry

    There's a test tube filled with a gas, and you bring a flame to the mouth of the tube. Many things could happen... The flame might get snuffed out and there might be a popping sound... so how can you find the density of that gas in relation to the air
  17. Chemistry

    Three colorless solutions in test tubes, with no labels, are in a test tube rack on the lab bench. Lying beside the test tubes are three labels: potassium iodide, KI, silver nitrate, AgNO3, and sodium sulfide, Na2S. You are to place the labels on the test
  18. Chemistry

    At 20.0 degrees celcius, a student collects H2 gas in a gas collecting tube. The barometric pressure is 755.2mm Hg and the water levels inside and outside the tube are exactly equal. What is the total gas pressure in the gas collecting tube?
  19. chemistry

    At 22.0 degrees Celsius , a student collects H2 gas in a gas collecting tube. The barometric pressure is 755.2mm Hg and the water levels inside and outside the tube are exactly equal. What is the total gas pressure in the gas collecting tube?
  20. Physics

    A test tube standing vertically in a test tube rack contains 2.4 cm of oil, whose density is 0.81 g/cm^3 and 6 cm of water. What is the gauge pressure on the bottom of the tube? The acceleration of gravity is 9.8 m/s^2. Answer in units of Pa
  21. Chemistry

    Some solid CaO in a test tube picks up water vapor from the surroundings to change completely to Ca(OH). An observed total initial weight (CaO + test tube) of 10.860 g goes eventually to 11.149 g. What is the weight of the test tube?
  22. check/bio!!!!

    okay the question is as follows: Three plants are placed in 3 different terrariums in 3 different light conditions. Plant A is placed in blue light, plant B in green light, and plant C in yellow light. In which case will there be an increase in the oxygen
  23. Chem

    Classify each of theses changes as a positive or negative change in entropy of a sample of this green gas. A) chlorine gas condense to a liquid = - B) chlorine gas is heated in a container= + C) chlorine gas deposits on a cold surface= -
  24. Chemistry

    A student places 5.77 grams of wex (a mythical substance often burned for light on other planets) in a test tube and then melts it. When the wex starts to freeze, the test tube (with the wex) is put into 237.6 g of water at 34.7oC. If the final temperature
  25. gravimetric prob

    A pure organic compound weighing 947.4mg was heated in a stream of oxygen. The effluent gas was swept successively through a tube of magnesium perchlorate dessicant weighing 18.6137g and a tube of Ascarite weighing 16.8425g. After several minutes the tubes
  26. Chemistry

    I did a lab where I had to decompose the compund patassium cholorate (KClO3)by heating,I had to weight the test tube then the test tube with the potassium chlorate to get the weight. I then had to heat it for several minutes and letting it cool down before
  27. Solubility/English

    Ok so I have this procedure to rewrite in past tense passive voice please help me out here I have alot ofthings to do with this lab...your help isgreatly appreciated. Thankyou! 1) Set up a hot-water both by placing th 250/400mL beaker, about two-thirds
  28. Chemistry

    A gas in a discharge tube consists entirely of ions of the same element, of the same charge. Each ion has only one remaining electron. The voltage between the electrodes of the gas discharge tube is increased from zero. Electrons are accelerated across the
  29. Science

    Can an element be separated from a compound? Can an element form a compound? The reaction of zinc metal and hydrochloric acid creates hydrogen gas, an element. if we create this element in a tube what property of this element requires us to keep the tube
  30. chemistry

    A scientist is performing an experiment on a powder. Which of the following is a sign that a chemical change has definitely occurred during his experiment? The powder catches on fire. The powder releases bubbles. The powder heats up. The powder breaks
  31. Chemistry Help

    If a graph is given for a cuvette using a 1.00 cm , predict the graph if a 2.0 cm diameter test tube and a 0.50cm test tube are used. The points for the 1.00cm test tube are (0,0),((2E-5),0.1), ((4E-5),0.2), ((6E-5),0.4), ((8E-5),0.5)...linear graph
  32. chemistry

    A gas in a discharge tube consists entirely of ions of the same element, of the same charge. Each ion has only one remaining electron. The voltage between the electrodes of the gas discharge tube is increased from zero. Electrons are accelerated across the
  33. English

    The green light is on. Let's walk across. The green light is on. Let's walk across the street. The green light is on. Let's walk across on the crosswalk. The green light is on. Let's walk across from the sidewalk. Are the sentences above all grammatical?
  34. Chemistry

    Questions: 1. In each test tube, a precipitate formed upon DROPWISE addition of the second reagent (steps 5 and 6). What are these precipitates? (a) First test tube with HgCl©ü : (b) Second test tube with SnCl©ü : 2. In each test tube, which reagent
  35. Chemistry PLEASE HELP!!

    Questions: 1. In each test tube, a precipitate formed upon DROPWISE addition of the second reagent (steps 5 and 6). What are these precipitates? (a) First test tube with HgCl©ü : (b) Second test tube with SnCl©ü : 2. In each test tube, which reagent
  36. Chemistry

    For my chemistry lab, I reacted Mg powder with HCl to create H2 gas. I measured the volume of H2 gas created by salt water displacement by reading off an inverted test tube. I measured 14.0 mL and calculated the percent yield (used PV=nRT to find
  37. Chemistry

    Purple light in the visible region of the electromagnetic spectrum has a shorter wavelength than does the green region of the spectrum. Which of the following can you conclude? Is it: a)a photon of purple light has a higher frequency than does a photon of
  38. chemistry

    Chlorine gas is collected in a gas collecting tube above water. The gas is at 20oC and the total pressure in the tube is 755 mmHg. What is the pressure (in mmHg) of chlorine gas in the tube?
  39. science

    we have done experiment in school and for homework we must write chemical reactions that have happend during the experiment. the experiment was like this : first we took an unknown substance than we have put some CuO , we mixed that two substances together
  40. science

    we have done experiment in school and for homework we must write chemical reactions that have happend during the experiment. the experiment was like this : first we took an unknown substance than we have put some CuO , we mixed that two substances together
  41. science

    we have done experiment in school and for homework we must write chemical reactions that have happend during the experiment. the experiment was like this : first we took an unknown substance than we have put some CuO , we mixed that two substances together
  42. Biochemistry

    Urea is heated in a test tube. A condensation reaction occurs. Which one? What is the formula for this reaction? Then cupper sulphate and sodium hydroxide is added to the tube. This is compared to a tube in which cupper sulphate, sodium hydroxide and a
  43. Chemistry

    Some solid calcium oxide in a test tube picks up water vapor from the surrounding to change completely into solid calcium hydroxide. An observed total initial weight (calcium oxide + test tube) f 10.860g goes eventually to 11.149g. What is the weight of
  44. Chemistry

    This question refers to spectroscopy. So why are certain colors used in this experiment? For example, why would a yellow light be used instead of a green light? And if I were to use a green light instead of a yellow light, would absorbance values be higher
  45. science- help needed.

    each statement is false. rewrite each one as a true statement,showing as much scientific understand as possible. 1. light waves travel slower than sound waves. 2.a black object will reflect white light. 3.a translucent object lets no light through. 4.an
  46. chemistry

    Assume you are in a lab with a test tube of sulfuric acid. You drop a piece of calcium into the tube. What do you observe happening in the tube? thank you
  47. chemistry

    You measure out 3.00 mL of 0.100 M Co(NO3)2, place it in a test tube and add 7.00 mL of water. What is the concentration of the diluted solution in the test tube?
  48. Chemistry

    CaO +H2O= Ca(OH)2 The initial mass plus the test tube is 10.860g after picking up water to give calcium hydroxide the total mass of the tube and ca(oh)2 is 11.149g What is the mass of the test tube? ..I did 11.149-10.86=.289 h2o , 40.08/56.08=ca %
  49. chem

    Consider a tube that is 1.0 meter long. If NH3 gas is introduce at the 0-m mark at the same time HCl gas is introduced at the 1-m mark, how far down the tube will the ring of gas occur?
  50. Absorption spectra of pigments

    On the graph light absorption in % vs wavelength, how come the color of chlorophyll is green? Since this is an absorption spectra, isn't it supposed to absorb blue and red and not green? Rather, it reflects green??? How would the graph be different if it
  51. physics

    A steel tube, which is closed at both ends, is filled with air. The air in the tube is vibrating at a frequency of 200·Hz. Use 340·m/s for the speed of sound in air. (a) What is the wavelength of the sound waves in the tube? _____ m. (b) If the 200·Hz
  52. science

    15. Two 5 dm3 flasks are connected by by a narrow tube of negligible volume. Initially the two flasks are both at 27 oC and contain a total of 2 moles of an ideal gas. One flask is heated to a uniform temperature of 127 oC while the other is kept at 27 oC.
  53. chemistry

    A student adds .137 grams of nickel(II) hydroxide powder to 10.0 L of distilled water at 25C with vigorous stirring. Did all of the powder dissolve? If not, how much powder remains undissolved? If so, how much more powder can be dissolved before a
  54. Physics

    A steel tube, which is closed at both ends, is filled with air. The air in the tube is vibrating at a frequency of 200·Hz. Use 340·m/s for the speed of sound in air. (a) What is the wavelength of the sound waves in the tube? m. (b) If the 200·Hz
  55. Science 8R - Safety in the Laboratory Help!!!!

    What was it called when you use this tube and you gently and carefully warming up the liquid using the gas using this thing that look like a scissor but your holding the tube on top of the gas. I forgot what it was, please tell me.
  56. Biology

    Plz i need help. Plants are green because the pigments in plants reflect green light. Blue and red light give them the most energy to power photosynthesis. You are conducting an experiment to see how different colors of light affect the growth of plants.
  57. Chemistry

    A gas in a discharge tube consists entirely of ions of the same element, of the same charge. Each ion has only one remaining electron. The voltage between the electrodes of the gas discharge tube is increased from zero. Electrons are accelerated across the
  58. Biology

    A series of laboratory experiments are set up to investigate various aspects of the photosynthetic process in Elodea canadensis, a common species of pond weed which lives underwater. In the experiment a fixed quantity of Elodea canadensis is incubated
  59. biology

    I have another experiment that I am not clear about the results. Any help? Put water, hydrogen proxide, and manganese dioxide powder in test tube, see what happens. Then put sand in the mixture. Results? Then,put liver in it. What happens? Thanks for
  60. Chemistry

    one morning you are given 3 test tubes of aqueous solutions of compound X: the "A" tube was set up as unsaturated, while "B" was set up as Saturated in a beaker, then poured of into the tube, and "C" was carefully set up as supersaturated. At lunchtime,
  61. chemistry

    A student added some bromine (reddish orange) in some carbon tertra chloride ro a sample of butane in a test tube and placed it in a dark cupboard. When the student removed the test tube it still had the reddish orange colour. When the test tube was left
  62. Chemistry

    24. Identify a source of error for the experimental design of the cobalt(II)chloride system In the experiment, there were three test tubes. All of them contained cobalt(II)chloride. Test tube 1 was the constant, therefore, did not change throughout the
  63. Physics

    If you place a glass test tube in water, you can see the tube. If you place it in clear soybean oil, you may not be able to see it. What does this indicate about the speed of light in the oil and in the glass?
  64. Chemistry

    1. Take a clean test tube from the Glassware shelf and place it on the workbench. Add 1 mL your mystery solution to the test tube. 2. PRECIPITATION BY NaC2H3O2(aq) (a) Add 2 mL of sodium acetate solution to the test tube. (b) If a white precipitate forms
  65. Chemistry

    Based on the spectrum of the fluorescent lamp, what is the main difference between the radiation emitted by a heated solid (filament) and the radiation emitted by an atomic gas (mercury gas in the fluorescent tube)?
  66. chemistry

    formula: 2KClO3 + NaCL = 2KCl + NaCl + 3O2 MASS OF TEST TUBE & MIXTURE = 34.03 G MASS OF EMPTY TEST TUBE = 31.29 G MASS OF MIXTURE = 2.74 G 1ST WEIGHT OF TEST TUBE & RESIDUE =33.64 G FINAL WEIGTH OF TEST TUBE & RESIDUE = 33.64 G MASS OF RESIDUE = 2.35 G
  67. scdience

    the density of gas was done twice, but with the tablet and 15 cm^3 of water in each case.When the rubber tube was placed as shown , 435 cm^3 of gas was collected. When the tube reached only slightly beyond the mouth of the bottle, only 370 cm^3 of gas was
  68. Science-Chemistry

    I did a lab on Elements and Compounds and I would be grateful if u could provide and tell me some information on my work. Lab --Investigation--Elements and compounds. Can an element be separated from a compound? Can an element form a compound? In this
  69. physics

    what kinetic energy does an electron acquire if it falls through a potential difference of 21,000 volts in a TV picture tube? How long will it take for that electron to travel from the "gun" end of the tube to strike the other end of the tube and create a
  70. Math Prob/solving

    As Frank drives to work he has to pass through three lights. The probability that any light is green is 39%. Estimate the probability that exactly two lights will be green. Use the following list of digits which was taken from a table of random numbers. In
  71. phys

    A motorist is driving at 20m/s{\rm m/s} when she sees that a traffic light 200m{\rm m} ahead has just turned red. She knows that this light stays red for 15s{\rm s} , and she wants to reach the light just as it turns green again. It takes her 1.0s{\rm s}
  72. lab!

    Use the following description of an experiment to answer the questions. A mixture was made of water and egg white (albumin). Upon heating, the mixture coagulated. The following tests were then performed on the coagulated mixture. Test Tube 1 The mixture is
  73. physics

    A cyclist is at rest at a traffic light. When the light turns green, he begins accelerating at 2.13 m/s2. How many seconds after the light turns green does he reach a cruising speed of 5.05 m/s?
  74. Science

    Based on the following information: A series of chemicals were added to some AgNO3(aq). NaCl(aq) was added first to the silver nitrate solution with the end result shown below in test tube 1, NH3(aq) was then added with the end result shown in test tube 2,
  75. physics

    A blue car pulls away from a red stop-light just after it has turned green with a constant acceleration of 0.2 m/s2. A green car arrives at the position of the stop-light 7.5 s after the light had turned green. What is the slowest constant speed which the
  76. Physics

    A blue car pulls away from a red stop-light just after it has turned green with a constant acceleration of 0.2 m/s2. A green car arrives at the position of the stop-light 7.5 s after the light had turned green. What is the slowest constant speed which the
  77. value

    what happens when a solution of iron 2 sulphate in a test tube was bubbled through chlorine gas
  78. College Physics

    A cyclist is at rest at a traffic light. When the light turns green, he begins accelerating at 2.56 m/s2. How far does he go after the light turns green until he reaches a cruising speed of 10.88 m/s?
  79. chemistry

    In an experiment, Ann mixes concentrated sulfuric acid with water in a reaction test tube. The walls of the test tube turn hot. What type of reaction has occurred?
  80. chemistry

    n an experiment, Ann mixes concentrated sulfuric acid with water in a reaction test tube. The walls of the test tube turn hot. What type of reaction has occurred?
  81. Chemistry

    You are given three test tubes that contain colourless liquid. One test tube contains benzene, another contains ethanol, and the third contains 2,4-hexadiene. Design a procedure that will tell you the contents of each test tube. Describe your expected
  82. Chemistry

    Which test tube has largest amount precipitate? Why? (use terms such as limiting reactant and excess reactant to explain) Do I just name the test tube that weighs the most and I need help with the explanation. I did not list the actual chemicals just need
  83. Chemistry

    1) When calcium is reacted with cold water, the equation is as follows: - Ca(s) + H2O(l) -->Ca(OH)2(aq) + H2(g) Isn't Ca(OH)2 insoluble? Why is the state symbol aqueous? When I conducted the experiment in a test tube with cold water, I got a white
  84. AP Physics B

    A soap bubble of index of refraction 1.43 strongly reflects both the red and the green components of white light. What minimum film thickness allows this to happen? (In air,the wavelength of red light is 703 nm, of green light 502.143 nm.) Answer in units
  85. Science

    * P is a a black powder, which, when fused with a mixture of potassium hydroxide and potassium nitrate and then treated with water yields a green solution. The green solution turn purple when acidified. -identify P, the green solution and purple solution.
  86. Physics

    The refractive index of a medium changes with the wavelength of incident light. Typically, the shorter the wavelength the larger the refractive index. Fused quartz has a refractive index of 1.47 for indigo light of 400 nm in wavelength, and a refractive
  87. Science

    A green leaf is reflecting a. no light b. red light c. green light d. all light C
  88. Chemistry check my answers

    Please check my answers For each of the 7 reactions in this experiment, write a balanced equation and classify it as a synthesis, decomposition, single replacemnt, neutralization, or double replacement reaction. Reaction 1 1)Adjust a burner flae to high
  89. Chemistry

    A student added some bromine (reddish orange) in some carbon tertrachloride to a sample of butane in a test tube and placed it in a dark cupboard. When the student removed the test tube it still had the reddish orange colour. When the test tube was left on
  90. Science

    Mr. Belvedere designs an experiment to test the effect of different colored light on the rate of photosynthesis. He sets up his experiment using elodea, 25watt bulbs, 30mL of distilled water, and 5g of sodium bicarbonate. Plant 1 is exposed to no light.
  91. Chem

    Solid ferric nitrate and aqueous sodium hydroxide are combined with water in a test tube. A brown to red precipitate forms in the test tube. Write a complete chemical reaction that accounts for the formation of the solid.
  92. physics

    Let's say you're driving in your car, approaching a red light on the Camp Hill Bypass. A black Porsche is stopped at the light in the right lane, but there's no-one in the left lane, so you pull into the left lane. You're traveling at 40 km/hr, and when
  93. Chemistry

    PRECIPITATION BY NaC2H3O2(aq) (a) Add 2 mL of sodium acetate solution to the test tube. (b) If a white precipitate forms at the bottom of the test tube, decant the remaining liquid into another clean test tube and retain the precipitate. (Decanting is the
  94. Chem

    If test tube 1: 2 grams KNO3 test tube 2: 4 grams KNO3 test tube 3: 6 grams KNO3 test tube 4: 8 grams KNO3 Why would test test tube #1 take longer to recrystallize?
  95. Physics

    The liquid in the open tube manometer is mercury, y1=3cm and y2 = 7cm. Atmospheric pressure is 980mbrs. (A) what is the absolute pressure at the bottom of the U-shape tube? (B) what is the absolute pressure in the open tube at a depth of 4 cm below the
  96. chem

    1) When a mixture of potassium chlorate and an appropriate catalyst is heated in an open test tube, potassium chloride and oxygen gas are produced. This reaction is not reversible, because a. the system reaches equilibrium b. the reaction does not go to
  97. biology

    A rock covered with green spots is placed on a screen in a test tube above some bromothymol blue solution; after several hours, the solution remains blue. What can you conclude form this experiment? AFter doing research, I found out that bromothymol
  98. Biology

    Has anyone done this experiment before? I need help with the final results. What would happen when I place 2 mL of hydrogen peroxide into 5 test tube, add manganese dioxide powder to the first one, then add sand to the second one, liver to the third one,
  99. Read Y9 chemistry

    4. Lead dioxide gives off a gas when heated. The gas relights a glowing splint. Give the name of this gas. 5. Hydrated cobalt chloride are dark red crystals. Give twoobservations you would make (what you would see) when these crystals are heated.
  100. chemistry

    pH Indicators 7 test tubes Added 5mL of water of 0.1 HCl and 5mL of water to 1st test tube. Poured 9mL of water to remaining 6 test tubes. Poured 1mL of solution from 1st test tube to 2nd. Poured 1mL from 2nd to third. Poured 1mL from 3rd to 4th. " " 4th