Saira

Popular questions and responses by Saira
  1. CHemistry...Please help

    Rank these liquids by their expected surface tension. Rank from greatest to least surface tension. 1.CH3CH2OCH3 2.CH3CH2CH2-OH 3.CH3CHOHCH2-OH 4.HO-CH2CHOHCH2-OH So as Dr. Bob mentioned to me before surface tension is how the surface molecules stick

    asked on January 19, 2009
  2. Chemistry

    Le Chateleir`s Principle Please check if my answers are right and i dunt know some of them: Consider the following system at equilibrium: A(aq)+B(aq) 2C(aq) Classify each of the following actions by whether it causes a leftward shift, a rightward shift, or

    asked on February 5, 2009
  3. Chemistry

    Given the two reactions 1.PbCl2 Pb^2+ + 2 Cl^-, K1= 1.82×10^−10 2. AgCl Ag^+ + Cl^-, K2 = 1.15×10−4 what is the equilibrium constant Kfinal for the following reaction? PbCl2+ 2 Ag^+ 2AgCl+ Pb^2+ This is what i have soo far: PbCl2Pb2+ + 2Cl- K1=

    asked on February 5, 2009
  4. CHemistry....Please help

    What mass of ethylene glycol C2H6O2, the main component of antifreeze, must be added to 10.0 L water to produce a solution for use in a car's radiator that freezes at -23C? Assume density for water is exactly 1g/mL. ----------------------------------- This

    asked on January 22, 2009
  5. Chemistry

    A 0.040M solution of a monoprotic acid is 14% ionized. Calculate the Ka for the weak acid. ---------------- so: HX H+ + X- Ka= [H+][X-]/ [HX] Since its a monoprotic acis i know the concentration of H and X will be equal And the HX will be 86% (100%-14%)

    asked on July 15, 2009
  6. Chemistry..

    A protein subunit from an enzyme is part of a research study and needs to be characterized. A total of 0.180 g of this subunit was dissolved in enough water to produce 2.00 mL of solution. At 28C the osmotic pressure produced by the solution was 0.138 atm.

    asked on May 29, 2009
  7. physics

    A person of mass 60 kg is standing on a raft of mass 40kg in a lake. The distance of a person from bank is 30m. If a person starts running towards bank with velocity 10m/s then his distance from bank after 1s will be ?? And explain with diagram and proper

    asked on September 16, 2014
  8. Chemistry: please double check...

    Please double check one last time have to hand it in tomorrow.Thank-You in Advance. This was the lab experiment: ------------------------------------------- A. Standardization of the Sodium Thiosulfate Solution Make up a standard solution of potassium

    asked on October 27, 2008
  9. Chemistry...Please Help

    The Chemicals are: Baking Soda- NaHC03 Calcium Chloride- CaCl2 Bromothymol Blue - (acid base indicator) _______________________________________ What is: (a) The equations for the dissolution of calcium chloride and sodium bicarbonate in water (b) Look up

    asked on January 6, 2009
  10. Math

    A 37-ft ladder leans against a building so that the angle between the ground and the ladder is 79∘. How high does the ladder reach on the building?

    asked on June 2, 2020
  11. computer sc.

    Draw a flowchart to calculate the average of 50 students in one subject.

    asked on July 13, 2016
  12. CHemistry....Please help

    How would i calculate the density of Li2S in grams per cubic centimeter? I have to use the equation : density= mass/ volume: But i don't know how to find out the volume using the edge length of the unit cell which is 5.88* 10^2 pm.

    asked on January 25, 2009
  13. CHemistry....Please double check DrBobb

    What mass of ethylene glycol C2H6O2, the main component of antifreeze, must be added to 10.0 L water to produce a solution for use in a car's radiator that freezes at -23C? Assume density for water is exactly 1g/mL. First we find out the freezing point:

    asked on January 24, 2009
  14. Chemistry

    Imagine that you are in chemistry lab and need to make 1.00 L of a solution with a pH of 2.70. You have in front of you * 100 mL of 6.00×10−2 M HCl, * 100 mL of 5.00×10−2 M NaOH, and plenty of distilled water. You start to add HCl to a beaker of

    asked on July 9, 2009
  15. Chemistry

    What happens to these physical properties as the strength of intermolecular forces increases? My answers are there as well but its not correct Increase or decrease? a) melting point - increases b) vapor pressure-increases c) boiling point- increases d)

    asked on May 11, 2009
  16. Chemistry

    Calculate the pH of a 0.10 M solution of barium hydroxide, Ba(OH)2.

    asked on March 2, 2010
  17. Art

    I need help understanding the Principles and Elements of Visual Arts with the help of images which examplify them...

    asked on November 4, 2009
  18. Chemistry

    Which of the following mixtures would result in buffered solutions when 1.0 L of each of the two solutions are mixed? a) 0.10 M NaCl and 0.10 M NaNO2 b) 0.10 M NaCl and 0.10 M NH4Cl c) 0.10 M CH3NH2 and 0.15 M CH3NH3Cl d) 0.10 M HCl and 0.05 M NaNO2 e)

    asked on August 11, 2009
  19. CHemistry....Please help

    1.SOLUBILITY: At 25C, the molar solubility of calcium phosphate in water is 1.1*10^{-7}M. Calculate the solubility in grams per liter. I m not sure how to convert M to g/L MOLAR MASS OF COLLIGATIVE PROPERTIES: 2.tert-Butyl alcohol is a solvent with a Kf of

    asked on January 24, 2009
  20. Health

    how can a disabled wheelchair person lead a normal life? how do they cook? etc

    asked on April 10, 2013
  21. health

    a dinner that includes all six nutrients? what can that be.please help me.

    asked on March 7, 2011
  22. health

    unhealthy fast food you can find list ingredents

    asked on February 1, 2011
  23. Chemistry

    How do i calculate: What is is ΔG° at 25 °C? 2O3(g) → 3 O2(g) ΔH° = -284 kJ ΔS° = 139 J/K i know the equation is: ΔG°= ΔH°- t (ΔS) im not getting right answer

    asked on April 22, 2010
  24. Chemistry

    Hey guys I did a lab and I have to answer the questions relating to the lab. I did question can someone please check if these are accurate 1. Calculation to Determine the molecular weight of unknown substance Mass of unknown used: 2.0232 g Mass of water

    asked on February 3, 2010
  25. Chemistry

    A 80.0 mL volume of 0.25 M HBr is titrated with 0.50M KOH. Calculate the pH after addition of 40.0 mL of KOH.

    asked on July 16, 2009
  26. Chemistry

    A mass of 0.630 g of NaCl is dissolved in 525 g of water. CAlculate the molality. mass of NaCl= 0.630g mass of H20= 525g molar mass of NaCl= 58.44 This is what i did it keeps telling me the answer is wrong. Convert grams to moles of NaCl 0.630 * 1 mol

    asked on May 21, 2009
  27. gr.10 history(a little question on world war one!!

    which countries were part of the triple entente in the first world war one?

    asked on February 18, 2009
  28. gr.10 math

    solve the linear system using substitution. please show me the steps!:) x-y=-5 2x-y=-7

    asked on February 16, 2009
  29. Plant Physiology

    Hey i have a mid term today at 3 , and this one sample question my prof posted online. If someone can please show me how to get the answers i would really appreciate it: A plant cell is found to have a Ψs = - 0.7 MPa and a Ψp = 0.5 MPa. Is this cell

    asked on February 13, 2009
  30. chemistry...DRBobb i have a questionnnn

    We actually talked about this before just to remind you im posting the previous post below: ______________________________________________________ ____________________________________________________ And i have a different question regarding a post someone

    asked on February 8, 2009
  31. Chemistry------DrBobb..

    Lead metal is added to 0.140 Cr^3+(aq). Pb(s)+ 2Cr^3(aq) Pb^2+(aq)+2Cr^2+(aq) KC=3.2*10^{-10} A. What is Pb^2+ when equilibrium is established in the reaction? B. What is Cr^2+ when equilibrium is established in the reaction? C. What is Cr^3+ when

    asked on February 7, 2009
  32. chemistry

    The "REVERSIBLE" chemical reaction- A + B C + D Kc = CD / AB =4.4 Concentration at the start and after equilibrium- A = 1.00 M --> (1.00 - X) M B = 2.00 M --> (2.00 - X) M C = 0.00 M --> X M D = 0.00 M --> X M 4.4 = X^2 / (1.00-X)(2.00 - X) I'm not sure

    asked on February 5, 2009
  33. Math please help...younger brother needs help

    1.HOW do you state the amplitude, period, phase shift and vertical shift for the function y= 2sin[4(angle symbol)-pie/2]-5? 2. Describe the function y= -5sin4 (angle symbol+30degrees)-4 as a transformation of the function y= sin(angle).

    asked on November 27, 2008
  34. Business

    My teacher said that Canada’s currently in the expansion phase (from the business cycle), but why is that so? What reasons support this?

    asked on June 20, 2018
  35. chemistry

    what is the molarity of the solution comtaining 2.5g of acetic acid in 75g of benzene

    asked on April 7, 2016
  36. Math

    Tony is 2/3 as old as Pete; the difference in their age is 4 years. How old is Pete?

    asked on November 17, 2015
  37. Math

    If Rita can type 55 words a minute, how many minutes to the nearest minute will it take her to type a 1695-word article?

    asked on July 5, 2015
  38. science

    when people remember memories after a memory loss, would you call those memories flashbacks or is there a different term? and is it possible for someone to lose memory for a specific event but remember everything after that? what is the term and are there

    asked on January 1, 2014
  39. Math!!!! *plz help*

    Use Brackets. Write Each Expression so that it equals the number in blue. a) 8+2x5 50 b) 6x3+1 24 c) 1+6x3+1 25 d) 2+8x5-1 49 e)7+14\7-5 14 f)12\2x5-4 2 Help Me Please i don't get what to do and how to.... ( \ stands for division)

    asked on September 10, 2012
  40. Math

    Use Brackets. Write Each Expression so that it equals the number in blue. a) 8+2x5 50 b) 6x3+1 24 c) 1+6x3+1 25 d) 2+8x5-1 49 e)7+14\7-5 14 f)12\2x5-4 2 Help Me Please i don't get what to do and how to.... ( \ stands for division)

    asked on September 10, 2012
  41. English

    What does fantastical mean? My essay topic is compare the fantastical in Poe and lawrence's "the rocking horse"

    asked on June 7, 2012
  42. chemistry

    What is the approximate energy required to raise the temperature of 5 L of air by 230 °C? The volume is held constant. (Assume air almost entirely consists of nitrogen, oxygen, and argon, and that it is initially at 273 K. Cv(specific heat) for

    asked on April 17, 2012
  43. chemistry

    What is the approximate energy required to raise the temperature of 5 L of air by 230 °C? The volume is held constant. (Assume air almost entirely consists of nitrogen, oxygen, and argon, and that it is initially at 273 K. Cv for nitrogen=20.7,oxygen=21

    asked on April 17, 2012
  44. languagge

    whats the natural resources of Japan ?

    asked on November 14, 2011
  45. math grade 5

    My sister in grade 5 needs help but i dunt exactly know how to do the answers myself, so if someone can help me out i can explain to her better. Thanks 3. You are using a tree diagram with 12 branches to show the possible outcome of a probability

    asked on June 6, 2011
  46. science

    a ball is thrown from a point 100m above the ground with speed 20m/s.find the velocity,direction and magnitude with which it strikes the ground?

    asked on June 1, 2011
  47. sciene

    how can solar power work at night

    asked on April 23, 2011
  48. science 5

    ts the est source of power in toronto please tell me i need help

    asked on February 24, 2011
  49. ancient civillation

    which lasted the longest. which lasted shortest. which began earliest. which began latest. Also what were the civillations that lasted 3000 years or more. please help i`m confused.

    asked on January 15, 2011
  50. social studies

    the habbitat and clothing of Ancient Civilizations – ancient Egypt please help. Thanks

    asked on January 14, 2011
  51. math

    what is 20 Jamaican dollars equal in Canada.

    asked on July 12, 2010
  52. spelling

    can you list some smaller words that are in perimeter and litre. thank you

    asked on April 21, 2010
  53. writting

    what does hewn mean? Also can i get a list of synonyms for objects , cutting , impact and act. please help!

    asked on April 7, 2010
  54. Chemistry

    IN the polystyrene beaker, mix 20mL of 0.1 M Acetic acid and 25mL of 0.1M Sodium Acetate and immediately measure the pH. Remove the electrode and add 5ml of 0.1 M HCl to this buffer. Stir the solution and measure the pH. _______________ INFO: concentration

    asked on March 28, 2010
  55. Chemistry

    Part A: Unknown Acid use 1gram and mix with 120 mL of distilled water Determine the concentration of the acid by titrating with 0.0998 M of NaOH Concentration of NaOH= 0.0998M Volume of NaOH= 3.5 mL # moles of NaOH= Initial Concentration of Weak Acid- Show

    asked on March 24, 2010
  56. Chemistry

    Hydrolysis of Salt: Using the universal indicator we had to determine the pH of sodium acetate, and the results i got was pH- 8.5 . Now i have to explain this with a equation to show hydrolysis. I don't know how to write it out but, Sodium is not

    asked on March 24, 2010
  57. duratioon

    how to calculate duration of a balance sheet

    asked on February 28, 2010
  58. 4th grade

    explain how farms today are different than medieval farms . Compare the farms. list a lot of differences and same things . please help!

    asked on February 15, 2010
  59. social studies, 4 thgrade

    what type of games do village people now play.

    asked on February 15, 2010
  60. 4th grade

    explain how village customs today are different than medieval times village customs.please help

    asked on February 14, 2010
  61. Chemistry

    Raoult's Law and Ionic or Organic Solutions At 55.0 C, what is the vapor pressure of a solution prepared by dissolving 62.8 g of LiF in 247 g of water? The vapor pressure of water at 55.0 C is 118 mmHg. Assume complete dissociation of the solute.

    asked on January 25, 2010
  62. Chemistry ....Please Double check

    If 4.55 g of sodium sulphide and 15.0 g of bismuth nitrate are dissolved in separate beakers of water which are then poured together, what is the maximum mass of bismuth sulphide, an insoluble compound, that could precipitate? What reactant was the

    asked on January 15, 2010
  63. Chemistry

    Rank the following ionic compounds by lattice energy. Highest to Lowest LiCl MgO Na2O Beo Na2S

    asked on January 15, 2010
  64. Chemistry ....Please help

    If 4.55 g of sodium sulphide and 15.0 g of bismuth nitrate are dissolved in separate beakers of water which are then poured together, what is the maximum mass of bismuth sulphide, an insoluble compound, that could precipitate? What reactant was the

    asked on January 14, 2010
  65. gr.10 math!

    factor the equation: -6x^2+15x+36 please show me the steps in answering this problem. thanksss..)

    asked on September 19, 2009
  66. Chemistry

    I am not really sure how to do this: Calculate the pH when 1.0*10^-3 moles of solid NaOH is added to a) One liter of 9.1*10^ -6 M HCL b) One liter of a solution containig 0.05 M CH3COOH and 0.1 M CH3CooNa

    asked on August 11, 2009
  67. Chemistry

    Buffers- Common Ion effect IS this Correct Calculate the pH of a aqueous solution containing 0.15 M HNO2 and 0.20 M NaNO2 (aq). The Ka of nitrous acid is 4.0*10^-4. HNO2 + H20 NaNO2- + H30^+ Inital 0.15 0.20 X Final 0.15 0.20 Ka= [H30+][NaNO2]/ [HNO2]

    asked on August 11, 2009
  68. Chemistry

    Hydrolysis of Salt: Using the universal indicator we had to determine the pH of potassium chloride, and the results i got was pH- 7.5 . Now i have to explain this with a equation to show hydrolysis. I dunno how to write it out, but i think KCL should be

    asked on July 19, 2009
  69. Chemistry

    I actually posted this up before and Gk helped out but i don't understand the steps what do i enter for the pka for the first one? __________________________________________ I did an experiment on Buffers: In a polystyrene beaker, mix 20 ml of 0.1M Acetic

    asked on July 19, 2009
  70. Chemistry

    A 80.0 mL volume of 0.25 M HBr is titrated with 0.50M KOH. Calculate the pH after addition of 40.0 mL of KOH.

    asked on July 16, 2009
  71. Chemistry

    I did an experiment on Buffers: In a polystyrene beaker, mix 20 ml of 0.1M Acetic acid ad 25 ml of 0.1 M sodium acetate and immediately measure the pH. Remove the electrode and add 5 ml of 0.1 M HCL to this buffer. Stir the solution and measure the pH.

    asked on July 16, 2009
  72. Chemistry

    A beaker with 150 mL of an acetic acid buffer with a pH of 5.00 is sitting on a benchtop. The total molarity of acid and conjugate base in this buffer is 0.100 M. A student adds 5.60 mL of a 0.280 M HCl solution to the beaker. How much will the pH change?

    asked on July 9, 2009
  73. Chemistry

    A new potential heart medicine, code-named X-281, is being tested by a pharmaceutical company, Pharma-pill. As a research technician at Pharma-pill, you are told that X-281 is a monoprotic weak acid, but because of security concerns, the actual chemical

    asked on July 7, 2009
  74. Chemistry

    i need help with a rate law question: The reaction is 2ClO2(aq) + 2OH -(aq)---> ClO3-(aq)+ ClO2-(aq) + H2O(l) Experiment 1: [ClO2]0= 0.0500 [OH-]0= 0.100 INITIAL RATE= 5.75*10^-2 Experiment 2: [ClO2]0= 0.100 [OH-]0= 0.100 INITIAL RATE= 2.30*10^-1

    asked on June 2, 2009
  75. Chemistry..Please Help

    HENRY'S LAW I did the first one im not sure how to do the 2 and the 3rd question. 1. What is the Henry's law constant for CO2 at 20{C}? C=kP K=c/p = 3.70*10^-2/1.00atm= 0.037 2. What pressure is required to achieve a CO2 concentration of 6.00×10−2 at

    asked on May 29, 2009
  76. Chemistry please help

    Hey guys I did a lab and I have to answer the questions relating to the lab. I did question can someone please check if these are accurate 1. Calculation to Determine the molecular weight of unknown substance Mass of unknown used: 2.0 g Mass of water used:

    asked on May 27, 2009
  77. MATH GRADE 3

    AT THE SPORT STORE THERE WERE 7 BIKES,1 UNICYCLE,AND 5 CARS PARKED IN THE LOT. HOW MANY WHEELS WERE THERE IN TOTAL? GIVE A NICE EXPLANATION WITH THE ANSWER PLEASE HELP.

    asked on May 20, 2009
  78. CHemistry

    Would someone please explain to me what intermolecular forces are. I don't really understand the whole concept.

    asked on May 18, 2009
  79. CHemistry

    My professor gave us these question in call and we solved for it in class, however im not sure how we got the answers. I dunt really understand the concept of intermolecular forces if some can please help me i have a quiz tomorrow. A. For each pair of

    asked on May 12, 2009
  80. Chemistry

    What is the solubility of calcium cholride

    asked on May 7, 2009
  81. Chemistry

    Write out the Ka and Kb for the biocarbonate ion with chemical equation: Would this be correct: HCO3^-(aq) H+(aq) + CO3^-2(aq) Ka = [H+][CO3-2]/[HCO3- H2O + CO3-2(aq) HCO3-(aq) + OH-(aq) Kb = [HCO3-][OH-]/[CO3-2] Or in my textbook there a chart that says:

    asked on May 7, 2009
  82. Urgent Chem Help

    Question.. Nicotinic acid (niacin) is a monoprotic acid with the formula HC6H4NO2. A solution that is 0.012M in the nicotinic acid has a pH of 3.39 at 25C. what is the acid-ionization constant, Ka and pKa for this acid at 25C? Attempt.. HC6H4NO2 C6H4NO2- +

    asked on March 15, 2009
  83. 3rd grade science

    1)list five ways germs were spread in pioneer days. 2)list the names of the various pioneer diseases.star the ones that make people sick today in north America. Can you please help me with my homework please.

    asked on March 5, 2009
  84. 3rd grade math

    1)which shapes are polygons. 2)which shapes have atleast one curved side.if you know this please help me as soon as posible because this is my homework

    asked on February 18, 2009
  85. 3rd grade math

    1)which shapes are polygons. 2)which shapes have atleast one curved side.if you know this please help me as soon as posible because this is my homework

    asked on February 18, 2009
  86. chemistry...Please Help

    I posted this below and received help but im still lost and worked out the problem but am getting the wring answer: -------------------- Given the equilibrium constant values: 1.N2(g)+ 1/2O2(g) N2O(g) KC=2.7*10^{-18} 2.N2O4(g) 2NO2(g) KC= 4.6*10^{-3} 3.

    asked on February 9, 2009
  87. Chemistry....Please help

    Given the equilibrium constant values: 1.N2(g)+ 1/2O2(g) N2O(g) KC=2.7*10^{-18} 2.N2O4(g) 2NO2(g) KC= 4.6*10^{-3} 3. 1/2N2(g)+ O2(g) NO2(g) KC=4.1*10^{-9} ----------------------------- 2N2O(g)+ 3O2 (g) 2N2O4(g) I need help i dunt know what to do next Part:

    asked on February 8, 2009
  88. Math

    How would i solve for Y: 3.2*10^-10= (y)(2y)^2/ (0.140-2y)^2

    asked on February 6, 2009
  89. Chemistry please help

    Lead metal is added to 0.140 Cr^3+(aq). Pb(s)+ 2Cr^3(aq) Pb^2+(aq)+2Cr^2+(aq) KC=3.2*10^{-10} A. What is Pb^2+ when equilibrium is established in the reaction? B. What is Cr^2+ when equilibrium is established in the reaction? C. What is Cr^3+ when

    asked on February 6, 2009
  90. Chemistry

    A mixture initially contains A,B, and C in the following concentrations: A1 = 0.300 M, B1 = 1.15M, and C1 = 0.350 M. The following reaction occurs and equilibrium is established: A+2B C At equilibrium, A2 = 0.190M and C2 = 0.460M. Calculate the value of

    asked on February 5, 2009
  91. Chemistry...Dr Bobb

    I have a midterm next week so i just wanted to make sure i understand: When we have a solid in a equation like: A(s) B(g)+ C(g) and we add more A why do the equilibrium not change and remain the same

    asked on February 5, 2009
  92. poem

    do you know a poem about for being sorry if you do please tell me i will be really happy and do it fast!

    asked on February 4, 2009
  93. 3rd grade

    what is 9x another # and same of 8x 7x 6x 5x 4x 3xn and more

    asked on February 4, 2009
  94. CHemistry....Please help...DrBobb

    I posted this up yesterday: I have to use the equation : density= mass/ volume: But i don't know how to find out the volume using the edge length of the unit cell which is 5.88* 10^2 pm. CHemistry....Please help - DrBob222, Sunday, January 25, 2009 at

    asked on January 26, 2009
  95. CHemistry....Please help

    How do you find out the coordination number of a crystal? For example im given a picture of the crystal structure of lithium sulfide Li2S. SO i need to find coordination number for: Li^+ S^2-

    asked on January 24, 2009
  96. Please double check...GK or Dr.Bobb22

    Hi, i actually posted this up before..please double check the answers if i got them right have to hand in on Wednesday: The Chemicals are: Baking Soda- NaHC03 Calcium Chloride- CaCl2 Bromothymol Blue - (acid base indicator)

    asked on January 19, 2009
  97. Chemistry..Please Help

    1. The vapor pressure of dichloromethane, CH2Cl2, at 0C is 134mmHg. The normal boiling point of dichloromethane is 40C. Calculate its molar heat of vaporization The answer is in kilojoules per mole. I know i use the Clausius-Clapeyron equation but i don't

    asked on January 18, 2009
  98. 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

    asked on November 20, 2008
  99. Chemistry please help

    Suppose that the microwave radiation has a wavelength of 12.4 cm. How many photons are required to heat 255 mL of coffee from 25.0 C to 62.0 C? Assume that the coffee has the same density, 0.997 g/mL, and specific heat capacity, 4.184 J/(g/ K), as water

    asked on November 3, 2008
  100. Human Physiology...Please Help

    Sensory Physiology Pick two types of sensory receptors: A. Pick two different modalities that would stimulate them B. Put these modalities in order with respect to adequate stimulus So if i was to pick, Photoreceptors and Thermoreceptors ( these would be

    asked on October 30, 2008

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