1. matrices

    Let A be a 5 by 4 matris and suppose that the system Ax=b has a solution. Explain why the solution is unique if and only if the rank of A is 4. I said that it is unique becaue the rank is equal to the number of columns. Do you have a better explaination.
  2. Water treatment

    If the RQ is 6 and the k2t is 4, what is the removal efficiency of (CO2) of the co-current tower aerator. What will be the efficiency if a tower aeration with counter current flow is used instead? what is the efficiency of the co-current tower aerator (%):
  3. Physics

    Engineers are trying to create artificial "gravity" in a ring-shaped space station by spinning it like a centrifuge. The ring is 100m in radius. How quickly must the space station turn in order to give the astronauts inside it weights equal to their
  4. Physics

    Engineers are trying to create artificial "gravity" in a ring-shaped space station by spinning it like a centrifuge. The ring is 100m in radius. How quickly must the space station turn in order to give the astronauts inside it weights equal to their
  5. Biology

    c. The cytoskeleton of eukaryotes serves many functions. One of these functions is served in eukaryotes by a different major structure. Which structural feature is it? How do these different structures serve the same function in the two cell types? Is it
  6. PHYSICS - PLEASE HELP

    Converting sunlight to electricity with solar cells has an efficiency of 15%. It's possible to achieve a higher efficiency (though currently at higher cost) by using concentrated sunlight as the hot reservoir of a heat engine. Each dish in the figure
  7. Technology~bobpursley

    25. Briefly explain the difference between product design and system design. 25. There are a few differences between system design and product design. System design deals with the arrangement of components to produce a desired result. For example,
  8. chemistry

    a metal crystallizes in the face centered cubic crystal structure with a unit cell edge of 5.48 x10 power of -8 cm. the density of the metal is 6.90 g per cubic cm. a. what is the mass (g) of a single atom of this element. b. what is the atomic weight of
  9. Designing Specialty Areas

    You're designing a space for families. Which of the following would be an important step in developing the space? A. Form a group of current teachers and teaching assistants to design the area. B. Hire a consultant to design the space. C. Have the director
  10. English

    1. May I take your order? 2. Would you like to order now? 3. Will you order? 4. Order, please. 5. Please order your food. 6. Are you ready to order? 7. Do you want to order? 8. Why don't you order? 9. How about ordering? 10. What do you think of ordering?
  11. Chemistry

    Draw the structure of the tripeptide “Asp-Ala-Ile” at pH = 1. Then determine the total charge of the tripeptide. The side chain of each amino acid is shown below in the form at pH = 7. (So when you use them to answer this question, you might need to
  12. economics

    Different market structures are prevailing in our different sectors like agriculture, power supply, transport industry, cement industry, restaurants, etc. Analyze and compare the characteristics of all market structure with respect to the given sectors.
  13. economics

    Different market structures are prevailing in our different sectors like agriculture, power supply, transport industry, cement industry, restaurants, etc. Analyze and compare the characteristics of all market structure with respect to the given sectors.
  14. Bio

    Proteins are manufactured from the "blueprints" found on DNA. After they are translated, they are moved through a system of internal membranes before being distributed throughout the rest of the cell. At some point in this process, they are modified to
  15. Bio- Chemistry

    How can you identify the difference between an plant and animal cell. What structures (you should have at least 2) should you look for in each in order to tell the difference?
  16. chem

    Are these correct? Rank the following species in order of increasing acidity. Explain your reasons of ordering them as you do. NH3 ,H2SO4, CH3OH, CH3COOH CH3COOH > H2SO4> CH3OH >NH3 Rank the following species in order of increasing basicity.
  17. Chemistry

    The question on one of my assignments says, "Explain why a thick layer of ice on the lake can support the weight of a person, but the liquid water cannot." I would assume it's because solids are solid and liquids are liquid, but I feel like they want a
  18. CHEM

    If NO3- has 3 resonance structures, but only one has to be written, where does the extra electron, making there then be 24 electrons, go if you cannot put brackets around the structure you are drawing? Do you put -1 on both of the singly bonded
  19. O.Chem -> PLEASE CHECK!!

    Please check these out for me, if I am correct: Match the following statements with SN1 or SN2 reactions: 1) The order of reactivity in alkyl halides is methyl>primary>secondary>tertiary 2) There is an intermediate carbocation 3) The rate-limiting
  20. percentile rank

    i would like to able to find the percentile rank of a z score 0.313152 can someone tell me how to do this.
  21. PSYCHOLOGY

    Why was the perspective followed by Wilhelm Wundt and his followers called structuralism? a. They wanted to identify the major brain structures. b. Their primary goal was to understand the physiology of the mind. c. They focused their efforts on
  22. Geology

    A crystal of zircon separated from an igneous rock, was analyzed, and found to contain 7930 atoms of 207Pb, and 12070 atoms of 235U. Knowing the half life of 235U is 713 million years, how old is the zircon crystal? Please show your calculations so that I
  23. finance (efficiency of management)

    The best indication of the operational efficiency of management is? A. net income B. earnings per share C. EBIT D. gross profit I like net income as a metric for operational efficiency because net income is how much money the company has after to paid all
  24. AP Statistics

    Suppose a Normal model describes the fuel efficiency of cars currently registered on your state. The mean is 24 mpg, with a standard deviation of 6 mpg. -Describe the fuel efficiency of the worst 20% of all cars. I know that you convert 20% into decimal
  25. **CHEM

    Place the following elements in order of Decreasing atomic size: tellurium, bromine, argon, cesium, strontium, and selenium. would the correct ranking then be: Cs, Sr, Te, Se, Br, Ar ??? or am I still way off??
  26. chemistry

    7. (a) Determine the crystal lattice energy for LiF(s) given that the ∆Hsubl for Li = 155kJ/mol, ∆H0f for F(g) = 78.99kJ/mol, IE1 of Li = 520kJ/mol, EA for Fluorine = -322kJ/mol and the ∆H0f LiF(s) = -589.5kJ/mol (b) For the following
  27. AP Chemistry

    I don't understand this question and answer can someone help me? In order to exhibit delocalized pi bonding, a molecule must have . At least resonance 2 resonance structures.
  28. chemistry

    Chemical analysis of a silicon crystal reveals gallium at a level of atomic percent. Assuming that the concentration of thermally excited charge carriers from the Si matrix is negligible, what is the density of free charge carriers (free carriers/cm3) in
  29. Math

    In order to begin advertising the single family homes, Bert asks Abigail to figure out the cost of each home, based on the company’s costs to build the entire development. After some additional adjustments, Abigail came up with the formula C space equals
  30. Chemistry

    1) it is found that .30 M solutions of the three shots Na3X, Na2Y and NaZ have pH's of 8.5, 7.0 and 10.5 not necessarily in order. (X,Y, and Z AE anions. Na is sodium ion) A) explain how anions can act as bases in aqueous solution. Write a chemical
  31. MATH

    A lattice point is a point with integer coordinates. How many lattice points $(x,y)$ with $-100\le x\le 100$ and $-100\le y\le 100$ are on the graph of the parametric equations \begin{align*} x&=30-40\cos t,\\ y&=-50 + 30\cos t? \end{align*}
  32. Chem

    Which molecule is not polar (possesses no net dipole)? Option 1. acetone [Marvin structure] Option 2. cis-dichloroethene [Marvin structure] Option 3. methylbromide [Marvin structure] Option 4. trans-dichloroethene [Marvin structure] Option 5.
  33. Chemistry

    If the RQ is 6 and the k2t is 4, what is the removal efficiency of (CO2) of the co-current tower aerator. What will be the efficiency if a tower aeration with counter current flow is used instead? what is the efficiency of the co-current tower aerator (%):
  34. science-chemistry

    how do the following changes affect the speed of a reaction? a)Increasing the concentration of the reactans. b)Decreasing the temperature. c)Decreasing the partickle size of a solid reactant.
  35. social studies

    which of the following contributed to Britain's industrial revolution? A. large labor force C. powerful monarchy B. decreasing food D. decreasing money
  36. Chemistry

    A student draws four resonance structures for nitromethane (CH3NO2). How many lewis structures should have been drawn to represent nitromethane?
  37. chemistry

    Chemical analysis of a silicon crystal reveals gallium at a level of 3.091*10^-7 atomic percent. Assuming that the concentration of thermally excited charge carriers from the Si matrix is negligible, what is the density of free charge carriers (free
  38. Chemistry

    Chemical analysis of a germanium crystal reveals indium at a level of 0.0003091 atomic percent. Assuming that the concentration of thermally excited charge carriers from the Ge matrix is negligible, what is the density of free charge carriers (free
  39. Chemistry

    Chemical analysis of a germanium crystal reveals indium at a level of 0.0003091 atomic percent. Assuming that the concentration of thermally excited charge carriers from the Ge matrix is negligible, what is the density of free charge carriers (free
  40. Chemistry

    Chemical analysis of a silicon crystal reveals gallium at a level of 3.091X10^-2 atomic percent. Assuming that the concentration of thermally excited charge carriers from the Si matrix is negligible, what is the density of free charge carriers (free
  41. chemistry

    Chemical analysis of a germanium crystal reveals indium at a level of 0.0003091 atomic percent. Assuming that the concentration of thermally excited charge carriers from the Ge matrix is negligible, what is the density of free charge carriers (free
  42. chemistry

    Chemical analysis of a germanium crystal reveals indium at a level of 0.03091 atomic percent. Assuming that the concentration of thermally excited charge carriers from the Ge matrix is negligible, what is the density of free charge carriers (free
  43. Business Management

    As your first job as the new manager at the outdated, adversarial company, write a plan for changing its organizational structure, incorporating the following elements: Your vision of the new organizational structure for your division including how you
  44. O.Chemistry *****PLEASE CHECK*****!!!!

    Please check these out for me, if I am correct: Match the following statements with SN1 or SN2 reactions: 1) The order of reactivity in alkyl halides is methyl>primary>secondary>tertiary 2) There is an intermediate carbocation 3) The rate-limiting
  45. grammar

    what is parrallel structure? Parallel structure is making sure that all parts of a series or other sentence constructions are using nouns, verbs, adjectives, etc., in the same order. There are some excellent examples here:
  46. Business

    Learning economics is like having you own crystal ball. The more you understand it as a social science, the more you understand how our economy and political system works. I say like a crystal ball, because you will be able to see things that other people
  47. Chemistry

    Chemical analysis of a silicon crystal reveals gallium at a level of 3.091×10−4 atomic percent. Assuming that the concentration of thermally excited charge carriers from the Si matrix is negligible, what is the density of free charge carriers (free
  48. Chemistry

    Chemical analysis of a silicon crystal reveals gallium at a level of 3.091×10−4 atomic percent. Assuming that the concentration of thermally excited charge carriers from the Si matrix is negligible, what is the density of free charge carriers (free
  49. chemistry

    Chemical analysis of a silicon crystal reveals gallium at a level of 3.091×10−2 atomic percent. Assuming that the concentration of thermally excited charge carriers from the Si matrix is negligible, what is the density of free charge carriers (free
  50. chemistry

    Chemical analysis of a silicon crystal reveals gallium at a level of 3.091×10−4 atomic percent. Assuming that the concentration of thermally excited charge carriers from the Si matrix is negligible, what is the density of free charge carriers (free
  51. Chemistry

    Rank these to highest pH to lowest pH: NH3, KOH, Ca(OH)2, HBr, HBrO I put these in the same order for highest pH to lowest but still get it wrong.
  52. Chemistry

    Rank the following molecules in order of increasing boiling point. NH3, CaCl2, Ar, CO, HF This is what I have, am I correct or on the right track? CaCl2, HF, NH3, CO, Ar
  53. Chemistry

    rank the gases Ar, N2,CH4, and C2H6 in order of the increasing density at STP answer: CH4<N2<C2H6<Ar please help me solve this
  54. chemistry

    Arrange the following aqueous solutions in order of decreasing freezing points (lowest to highest temperature): 0.10 m Na3PO4, 0.35 m NaCl, 0.20 m MgCl, 0.15 m C6H12O6 and 0.15 m CH3COOH.
  55. Chemistry

    Arrange the following compounds in order of decreasing ease of elution from a column of silica gel: a) 2-octanol; b) 1,3-dichlorobenzene; c) tert-butylcyclohexane; d) benzoic acid
  56. Chemistry

    Arrange the following compounds in order of decreasing ease of elution from a column of silica gel: a) 2-octanol; b) 1,3-dichlorobenzene; c) tert-butylcyclohexane; d) benzoic acid
  57. science

    The lanthanide metal europium (Eu) forms a crystalline solid with a cubic unit cell of edge length 3.854 Å. The density of europium is 4.408 g cm-3. The crystal structure of solid europium is a. body-centered cubic b. simple cubic c. face-centered cubic
  58. Analytical CHM

    Rank the following items in order of accuracy: volumetric pipet, beaker,buret,erlenmeyer flask,volumetric flask
  59. Organic Chemistry

    Rank the following compounds in order of increasing acidity. a. H2O, H3O-, Ho- == HO-, H2O, H3O- b. NH3
  60. Chem

    Give three examples each of household items that have: a. different structures and exhibit different properties b. same chemical make-up composition but a different structure, hence, different properties c. the same properties but with different chemical
  61. Chemistry

    How do I know the order of placing dots on the lewis structure? Please give an example.
  62. Chemistry

    Choose the true statements regarding the charge-minimized Lewis structure(s) of the BrO2- ion. (selet all that apply) a. There is only one charge-minimized structure for this ion. b. There are two charge-minimized resonance structures for this ion. c. The
  63. chemistry

    Arrange the following in decreasing order of their massess . a. 2.5 moles of water. b. 3.012×10×24 c. 25 g of water
  64. CHEMISTRY

    Chemical analysis of a silicon crystal reveals gallium at a level of 3.091×10−8 atomic percent. Assuming that the concentration of thermally excited charge carriers from the Si matrix is negligible, what is the density of free charge carriers
  65. CHEMISTRY

    Chemical analysis of a silicon crystal reveals gallium at a level of 3.091×10−8 atomic percent. Assuming that the concentration of thermally excited charge carriers from the Si matrix is negligible, what is the density of free charge carriers
  66. chemistry

    Chemical analysis of a silicon crystal reveals gallium at a level of 3.091×10−8 atomic percent. Assuming that the concentration of thermally excited charge carriers from the Si matrix is negligible, what is the density of free charge carriers
  67. chemistry

    Chemical analysis of a silicon crystal reveals gallium at a level of 3.091×10−3 atomic percent. Assuming that the concentration of thermally excited charge carriers from the Si matrix is negligible, what is the density of free charge carriers
  68. chemistry

    Chemical analysis of a silicon crystal reveals gallium at a level of 3.091×10−8 atomic percent. Assuming that the concentration of thermally excited charge carriers from the Si matrix is negligible, what is the density of free charge carriers
  69. Calculus

    The fuel efficiency, E, in litres per 100 km, for a car driven at speed v, in km/h is E(v)=1600v/(v^2+6400) a)If the speed limit is 50 km/h, determine the legal speed that will maximize the fuel efficiency. Could someone explain to me why the legal speed
  70. chem

    Rank these in order of increasing freezing points: C2H6O, NaCl, NaSO4, C12H22O11 I suggest that you look them up. You will have to make an assumption at the isomer of the organic compounds that is intended, but it will not make a difference to the ranking.
  71. chem hw

    Assuming equal concentrations, rank these aqueous solutions by their freezing point: Li2SO4, Li3PO4, SnCl4, NH4Br. (from highest freezing point to lowest freezing poinT) Is the order Li3PO4, Li2SO4, SnCl4, and NH4Br???????? If not what is the correct
  72. Science

    Silicate materials have a variety of crystalline structures, even though they are made from the same building blocks --- silica tetrahedra. what factors do you think affect the structures of silicate minerals as they are forming? please help
  73. management structures

    Give an example of how each of the following management structures affects the day-today work of an organization. 1. Departmentalization- 2. Matrix Organizations 3. The Project Team 4. The Collegial Model
  74. Chemistry

    Two isomers have the same formula but different structures: Co(H2O)5SCN, CO(H2O)5NCS. The 5's mean 5-H20's. Draw each of these structures and explain the difference between the two? I don't even know where to begin. I appreciate any kind of help at this
  75. Chemistry

    Generally, the solubility of gases in liquids increase with a-decreasing temperature & increasing pressure b-increasing temperature & decreasing pressure c-decreasing temperature & decreasing pressure d-increasing temperature & increasing pressure
  76. math

    If a student's percentile rank in a class of 400 students is 87, find the student's class rank.
  77. Math

    If a student's percentile rank in a class of 400 students is 87, how do I find the student's class rank.
  78. physics

    The objects listed below are placed at the top of a ramp, and roll down to the bottom without slipping. Assuming that there is no air resistance, rank them in order from fastest average rolling speed to slowest. Penny, large marble, basketball, and hula
  79. Physics

    The objects listed below are placed at the top of a ramp, and roll down to the bottom without slipping. Assuming that there is no air resistance, rank them in order from fastest average rolling speed to slowest. Basketball Bowling Ball Penny Wedding Ring
  80. Healthcare Management

    Which of the following statements about reorganization is true? A. Organizational structure must be changed to accommodate changes in strategy. B. Managers shouldn't waste their time reevaluating organizational structure and processes. C. An organization's
  81. PLEASE HELP-PHYSICS HW

    A 130 kg astronaut (including space suit) acquires a speed of 2.80 m/s by pushing off with his legs from an 2000 kg space capsule. What is the change in speed of the space capsule? As the reference frame, use the position of the space capsule before the
  82. Physics

    A 120 kg astronaut (including space suit) acquires a speed of 3.00 m/s by pushing off with his legs from an 1900 kg space capsule. What is the change in speed of the space capsule? As the reference frame, use the position of the space capsule before the
  83. Physics

    A 160 kg astronaut (including space suit) acquires a speed of 2.20 m/s by pushing off with his legs from an 1950 kg space capsule. What is the change in speed of the space capsule? As the reference frame, use the position of the space capsule before the
  84. Physics

    A 160 kg astronaut (including space suit) acquires a speed of 2.20 m/s by pushing off with his legs from an 1950 kg space capsule. What is the change in speed of the space capsule? As the reference frame, use the position of the space capsule before the
  85. chemistry

    Chemical analysis of a silicon crystal reveals gallium at a level of 3.091×10−6 atomic percent. Assuming that the concentration of thermally excited charge carriers from the Si matrix is negligible, what is the density of free charge carriers
  86. Fraction word problem

    A structure is made out of foam cubes that are each 1/4 foot tall. The height of the structure is 8 feet. How many cubes were used to build the structure? Is this how we write 8➗1/4=8
  87. Chemistry Please helpppp

    Molecular Orbitals 1.Which of the following diatomic species are paramagnetic and which are diamagnetic? a.C2^2+ b.B2^2- c.Li2^- 2.Arrange the following in order of decreasing stability. a.F2 b.F2^- c.F2+ I know that as you go to higher subshells like from
  88. chemistry

    Given the compounds H2S, NH3, and SO2. Determine the order o boiling points. Rank them from highest to lowest boiling point. Give an explanation for your ranking by the electronegativity data a by type of intermolecular force.
  89. algera

    The fuel efficiency for a certain midsize car is given by E(v) = −0.018v^2 + 1.440v + 3.9 where E(v)is the fuel efficiency in miles per gallon for a car traveling v miles per hour. (a) What speed will yield the maximum fuel efficiency? Round to the
  90. Algebra

    The fuel efficiency for a certain midsize car is given by E(v) = −0.017v^ + 1.462v + 3.5 where E(v)is the fuel efficiency in miles per gallon for a car traveling v miles per hour. (a) What speed will yield the maximum fuel efficiency? Round to the
  91. physics

    Two Astronauts A and B are working in the space shuttle in the space.Suddenly the hammer falls from the hands of astranaut in space. who will hear most sound,Astranonaut A or B .and why?
  92. Sociology

    Analyze the functions of the family by addressing the ideal family structure as it compares to real family structures. In essence, compare the ideal and real culture of the American family.
  93. Physics

    A CsCl (cesium chloride) salt crystal is built from the unit cells shown in the figure below. Cl− ions form the corners of a cube and a Cs+ ion is at the centre of the cube. The edge length of the cube, which is called the lattice constant, is 0.4
  94. Chemistry - Order of Bond Polarity

    Hi I am having a bit of trouble with this question CCl4 is confusing me: Qu)Rank the following compounds in order of bond polarity; HF, CH4, H2O, H2S, CCl4 Asw)lowest to highest bond polarity: CH4, CCl4, H2S, H2O, HF Is this correct? Thanks!
  95. Chemistry

    a chemist needs to order Na2B4O7. One supplier offers it in an anhydrous (without water) form, while another offers it as a hydrated crystal, Na2B4O7*10H20. if the prices from the two suppliers are the same for a 500.0-g bottle, which one would supply more
  96. Computers (Java)

    Hello -- Looking for help with an extra credit assignment to give my grade a needed boost. The program is to display a star pattern with java loops. From prof: 7. Write a program using loops to display the star pattern that follows the written description.
  97. Computers (Java)

    Hello -- Looking for help with an extra credit assignment to give my grade a needed boost. The program is to display a star pattern with java loops. From prof: Write a program using loops to display the star pattern that follows the written description.
  98. CHEM

    For a crystal with formula BaCl2.xH2O, a student conducted a gravity experiment and found out that 2.44 gram of this crystal can lost mass 0.36 gram when heated to 150 degree. Suppose water is the only reason of weight loss, what is the x value here?
  99. Economics

    Which of the following results from having a nation having conflicting economic goals? A. the nationalizing of some industries B. the need to rank choices in order of importance C. the need for economic safety nets D. government regulation of domestic
  100. physics

    A hydraulic jack is designed so that when the handle is pushed down 1 m, the piston raising the load moves up 0.015 m. IMA= 66.67 AMA= 26.67 Efficiency= 40% At this efficiency, what is the force required to lift a 5000 N weight?