1. Chemistry

    If a sample of K3PO4 is found to contain 1.81 grams of K+ ions, how many PO3- 4 ions are present?

    asked by Heather on July 31, 2011
  2. chem

    A scientist wants to make a solution of potassium phosphate, K3PO4 for a lab experiment. How many grams of K3PO4 will be needed to produce 575ml of a solution that has a concentration of K+ ions of 1.4M.

    asked by alex on May 10, 2011
  3. Chemistry

    I'm not really sure how to do this. I've tried many ways and I can't get the right answer of 0.0569 mol/L H3PO4 100.0 mL of a solution containing 2.55g of potassium hydroxide is mixed with 100.0 mL of a 1.50 mol/L phosphoric acid solution. Will the

    asked by Sarah on December 17, 2017
  4. chemistry

    If you dissolve 236.5 g of (NH4)3PO4 and 166.9 g of K3PO4 in enough water to make the volume of the solution 505.0 mL What is the molarity of ammonium ions and phosphate ions?

    asked by Jade on November 2, 2014
  5. molarity

    calculate the molarity of k+ in a soln prepared by adding .2L of .200M K3PO4 and 75.0mL of .5M K3PO4. assume volumes are additive. A few of steps here and more than one way to answer the problem You need to calculate the total number of moles of K3PO4 from

    asked by Christine on April 5, 2007
  6. AP Chemistry

    Consider the following reaction: PbCl2 + 2 NaOH → Pb(OH)2 + 2 NaCl What would be the major species observed floating in solution after one mole of PbCl2 and 2 moles of NaOH are mixed in aqueous solution? 1. Na+ ions, Cl− ions and H+ ions 2. Pb2+ ions,

    asked by Sam on April 18, 2016
  7. Chemistry

    Consider the following reaction: PbCl2 + 2 NaOH -> Pb(OH)2 + 2 NaCl What would be the major species observed floating in solution after one mole of PbCl2 and 2 moles of NaOH are mixed in aqueous solution? 1. Na+ ions, Cl− ions and H+ ions 2. Pb2+ ions,

    asked by Cher on April 5, 2010
  8. chemistry

    If you pass 10.0mL of a 50.0mL solution of [Co(en)2Cl2]Cl that has been reduced with Zn through a cation exchange column, you will obtain a solution that has three H+ ions for every Co3+ ion that was originally present in the sample. These H+ ions are

    asked by xx on October 26, 2014
  9. Chemistry

    The Cu2+ ions in this experiment are produced by the reaction of 1.0g of copper. Information already found out .016 mol Cu2+ produced Overall reaction is Cu2+(aq)+Cl-(aq)+Cu(s)=2 CuCl(s) Maximum mass of CuCl that can be prepared from the reaction sequence

    asked by Julie on October 23, 2012
  10. Chemistry

    H3PO4(aq) + 3 KOH(aq) → K3PO4(aq) + 3 H2O(l) How many grams of potassium hydroxide are required to completely neutralize 3.23 grams of phosphoric acid?

    asked by ... on November 2, 2015
  11. chemistry

    What is the theoretical yield in grams of the precipitate starting with 1.250 moles of iron ions (charge is +3) and 60.00 grams of hydroxide ions?

    asked by matt on November 7, 2008
  12. Chemistry

    Part 1 : a.) How many grams of Hydrogen will be contained in a 100.000 g sample of magnesium hydroxide.? c.) How many grams of nitrogen will be contained in a 120.0 g sample of calcium cyanide? ________________________________________ Part 3: d.) How many

    asked by Amber Deana B. on January 11, 2016
  13. chemistry

    how many totsl moles of ions are released when 0.83 mol of K3PO4 dissolves in water?

    asked by samm on October 28, 2009
  14. Intro Chemistry

    If a sample of BaSO3 is found to contain 1.73 · 1018 SO32- ions how many moles of Ba2+ ions are present? Express your answer in scientific notation. The following information is given: Molar Mass (g/mol) BaSO3 217.39 Ba2+ ion 137.33 SO32- ion 80.063

    asked by echem on March 13, 2010
  15. Chemistry (moles)

    A 1.00L sample of seawater contains 19.4g of chloride ions, 10.8 g of sodium ions, and 1.29 g of magnesium ions. How many more moles of chloride ions would be needed to make neutral salts of all the cations in solution?

    asked by Toni Jones on February 28, 2011
  16. science

    how many ions of potasium are there in 4.2vgrams of K3PO4 (molar mass=212.264g/mol )

    asked by Anonymous on February 2, 2013
  17. Chemistry

    A sample of lithium sulfate, Li2SO4, contains 6.78 x 10^23 formula units. a) How many moles of Li+ ions are there in the sample? b) How many moles of ions are there in the sample? My work. I think a) is 2.26 is that correct?

    asked by Secila on November 24, 2014
  18. 9th grade chemistry

    if you have 55.6 grams of nitrate ions in a compound that consists of nitrate ions and plumbous ions, how many grams of the compound do you have? how do i do this problem im completely stuck!?

    asked by lyne on December 10, 2008
  19. CHEMISTRY HELP

    if you have 55.6 grams of nitrate ions in a compound that consists of nitrate ions and plumbous ions, how many grams of the compound do you have? how do i do this problem im completely stuck!?

    asked by lyne on December 10, 2008
  20. stat

    1. The amount of pyridoxine (in grams) per multiple vitamin is normally distributed with = 110 grams and = 25 grams. A sample of 25 vitamins is to be selected. So, 95% of all sample means will be greater than how many grams?

    asked by Anonymous on December 1, 2010
  21. chemistry

    A sample of oxygen at 24.0 degrees celcius and 99.3 kpa was found to have a volume of 455 ml. How many grams of O2 were in the sample?

    asked by nicole on January 13, 2015
  22. Chemistry

    If a sample of Co2(CO)8 is found to contain 6*10^-2 mol of C atoms, how many grams of Co atoms are present? Molar Mass (g/mol) Co2(CO)8 - 341.95 Co atom - 58.933 C atom - 12.011 O atom - 15.999 Avaogadro's No.: 6.022*10^23 Do I need to use the 6*10^-2 mol

    asked by Kyle on January 16, 2012
  23. Chemistry

    A sample of lithium sulfate, Li2SO4, contains 6.78 x 10^23 formula units a) How many moles of Li+ ions are there in the sample b) How many moles of ions are there in the sample

    asked by Mimi on November 24, 2014
  24. Chemistry

    What is the concentration of the resulting solution when 250 mL of 0.1 M K3PO4 and 300 ml of 0.5 M K3PO4 are mixed?

    asked by L on June 10, 2013
  25. ap chemistry

    18. Answer the following question that relate to the analysis of chemical compounds. (a) A compound containing the elements C, H, N, and O is analyzed. When a 1.2359g sample is burned in excess oxygen, 2.241g of CO2(g) is formed. The combustion analysis

    asked by alk on December 27, 2007
  26. chemistry

    Write the formula of the ionic compound that forms between a. copper(I) ions and chloride ions---CuCl b. copper(II) ions and hydrogen sulfate ions--Cu(HSO4)2 c. lithium ions and iodide ions--LiI d. cobalt(III) ions and phosphate ions---CoPO4

    asked by krystal on February 6, 2012
  27. chem090

    100.0 g of Potassium Phosphate reacts with 100.0 g of Barium Chloride. Which molecule is completely used up by the reaction? How many grams of the other molecule are left over? When I started with 100.0 g of K3PO4 I got 147.1g of BaCl2. When I started with

    asked by Jenny on April 14, 2014
  28. biochem

    Two samples of double-stranded DNA have been prepared. Nucleotide analysis reveals that sample 1 is found to be 21% A, while sample 2 is 26% G. Knowing this, which of the following statements is true? Sample 1 has a higher AT content than Sample 2. Sample

    asked by Kate on April 26, 2017
  29. Chemistry

    Write the chemical formula and number of ions formed when the following electrolyte dissolves in water. Make sure to include appropriate states. K3PO4 = ??? Any help with this is greatly appreciated!

    asked by Amanda on February 8, 2014
  30. Chemistry

    A sample of lithium sulfate, LiSO4, contains 6.78 x 10^23 formula units. a) How many moles of Li+ ions are there in the sample? b) How many moles of ions are there in the sample? My work: I think a) is 2.26 moles And b i am not sure

    asked by Mimi on November 24, 2014
  31. ap chemistry

    What is the ratio of the molarities of PO3^4- and HPO4^2− ions in a buffer solution having a pH of 13.16? What mass of K3PO4 must be added to 1 L of 0.1 M K2HPO4(aq) to prepare a buffer solution with a pH of 13.16? Answer in units of g What mass of

    asked by gabriella on February 4, 2014
  32. chemistry

    _H3PO4+_KOH->_K3PO4+_H2O if 49.0 g of H3PO4 is reacted with excess KOH, determind the percent yield of K3PO4 if you produce 49.0 g of K3PO4.

    asked by kelly on November 10, 2012
  33. chem

    for my last two questions, i had Krypton as the element and 56.96 grams K3PO4. i need something to compare with

    asked by alex on May 10, 2011
  34. Chemistry

    Caffeine C8H10N4O2, is a stimulant found in a tea and coffee. A sample of the substance was dissolved in 45.0g of choloroform CHCl3 to give a 0.0946m solution. How many grams of caffine were in the sample. m = molality

    asked by Lauren on February 6, 2008
  35. Chemistry 101 Electrolytes

    What is the total number of ions formed when 2.00 grams of calcium chloride are dissolved in 100 grams of water. (Ignore any ions formed by the water). Note, this is a bit of a trick question. Read the problem carefully.

    asked by Gweedo8 on June 1, 2009
  36. Chemistry Electrolytes

    What is the total number of ions formed when 2.00 grams of calcium chloride are dissolved in 100 grams of water. (Ignore any ions formed by the water). Note, this is a bit of a trick question. Read the problem carefully.

    asked by Gweedo8 on June 1, 2009
  37. Chemisty 20

    A sample of water was known to contain chloride ions. To determine the concentration of chloride ions in the water sample, a student added a solution of silver nitrate to 500mL of the water. 1.26g of silver chloride percipitate formed. What was the

    asked by James on November 14, 2012
  38. chemistry

    When 2 moles of K3PO4 is dissolved in water, how many moles of ions are produced? For your answer do not put units, just the numeric value.

    asked by Austin on November 14, 2018
  39. chemistry

    A sample of silver chromate (Ag2CrO4) has a mass of 29.0 g. (a) How many Ag+ ions are present? (b)What is the mass in grams of one formula unit of silver chromate? (c) How many CrO42- ions are present?

    asked by q on January 13, 2010
  40. chemistry

    How many grams of K3PO4 would be needed to prepare a 1.73 M solution in a total volume of 427 mL?

    asked by Lauren on October 12, 2011
  41. chemistry

    How many grams of K3PO4 would be needed to prepare a 1.73 M solution in a total volume of 427 mL?

    asked by Lauren on October 12, 2011
  42. chemistry

    2.) If you pass 10.0mL of a 50.0mL solution of [Co(en)2Cl2]Cl that has been reduced with Zn through a cation exchange column, you will obtain a solution that has three H+ ions for every Co3+ ion that was originally present in the sample. These H+ ions are

    asked by xx on October 26, 2014
  43. chemistry

    2.) If you pass 10.0mL of a 50.0mL solution of [Co(en)2Cl2]Cl that has been reduced with Zn through a cation exchange column, you will obtain a solution that has three H+ ions for every Co3+ ion that was originally present in the sample. These H+ ions are

    asked by Anonymous on October 26, 2014
  44. chemistry

    2.) If you pass 10.0mL of a 50.0mL solution of [Co(en)2Cl2]Cl that has been reduced with Zn through a cation exchange column, you will obtain a solution that has three H+ ions for every Co3+ ion that was originally present in the sample. These H+ ions are

    asked by xx on October 26, 2014
  45. chemistry

    A sample of water is found to contain 0.059 ppm of Pb2+ ions. Calculate the mass of lead ions per liter of this solution (assume the density of the water solution is 1.0 g/mL) 1.2E-2 g/L Pb2+ 5.9E-8 g/L Pb2+ 5.9E-5 g/L Pb2+ 1.2E-5 g/L Pb2+ 2.9E-10 g/L Pb2+

    asked by Heaton on February 5, 2012
  46. College Chemistry

    The concentration of lead ions (Pb^2+) in a sample of polluted water that also contains nitrate ions (NO3) is determined by adding solid sodium sulfate (Na2SO4) to the sample of the water. Write the net ionic equation for the reaction. Do not forget to

    asked by KELLY on September 27, 2010
  47. statistics

    A simple random sample of a size n is drawn from a population that is normally distributed. The sample mean, x is found to be 110, and the sample standard deviation, s, is found to be 10. A- Construct a 95% confidence interval about u if the sample size,

    asked by Anonymous on March 29, 2015
  48. chemistry

    You are a chemist requested to review and analyse certain debris found on thebottom of aboot found in a crime scene. The debris contains metal fragments. If you identify the metal fragments---it will help the detctive identify the locations traveled by the

    asked by Jimmy on February 26, 2012
  49. chemistry

    If you pass 10.0mL of a 50.0mL solution of [Co(en)2Cl2]Cl that has been reduced with Zn through a cation exchange column, you will obtain a solution that has three H+ ions for every Co3+ ion that was originally present in the sample. These H+ ions are

    asked by xx on October 26, 2014
  50. Chemistry

    How many moles of ammonium ions and how many moles of sulfate ions are contaiuned in a 0.400 mile sample of (NH4)2SO4? Referring to the 0.400 mole sample of (NH4)2SO4 on the previous page, how many atoms of N,H,O, and S, are contained in this sample?

    asked by Chelsea on September 23, 2015
  51. Pre Calculus

    Tritium, a radioactive isotope of hydrogen, has a half-life of 12.4 years. Of an initial sample of 69 grams, how much will remain after 75 years? a. 1.5848 grams b. 61.5289 grams c. 0.0000 grams d. 1.0426 grams e. 17.2500 grams

    asked by Jessica Maths on July 6, 2016
  52. chemistry

    What mass of K2HPO4 must be added to 1 L of .1 M K3PO4 to prepare a buffer solution with a pH of 10.8? Answer in units of grams.

    asked by Avery on March 9, 2016
  53. chemistry

    For the determination of the quantity of chloride in a physiological serum sample by the Volhard method, a sample of 25.00 ml was treated with 50.00 ml of 0.110 mol/L Silver nitrate solution and the excess of silver ions was titrated with 17.00 ml of a

    asked by william on October 4, 2017
  54. chemistry

    A 2.9-L sample of paint that has a density of 4.65 g/mL is found to contain 26.7 g Pb3N2(s). How many grams of lead were in the paint sample?

    asked by caroline on September 25, 2010
  55. Chemistry

    Determine the starting mass of each reactant if 46.3 of K3PO4 is produced and 92.8 of H3PO4 remains unreacted. 3KOH + H3PO4 ----> K3PO4 + 3H2O

    asked by Anonymous on May 8, 2017
  56. Chemistry

    Determine the starting mass of each reactant if 46.3 of K3PO4 is produced and 92.8 of H3PO4 remains unreacted. 3KOH + H3PO4 ----> K3PO4 + 3H2O

    asked by Anonymous on May 8, 2017
  57. chemistry

    What volume of 0.714 M K3PO4 is required to react with 27 mL of 0.97 M MgCl2 according to the equation 2 K3PO4 + 3 MgCl2 → Mg3(PO4)2 + 6 KCl Answer in units of mL

    asked by Anonymous on October 28, 2013
  58. AP Chemistry

    What volume of 0.149 M K3PO4 is required to react with 41 mL of 0.793 M MgCl2 according to the equation 2 K3PO4 + 3 MgCl2 → Mg3(PO4)2 + 6 KCl Answer in units of m

    asked by Yolanda on October 7, 2011
  59. CHem

    How many oxygen atoms do you have in 2.00 grams of calcium phosphate? My answer is 3.9*10^22 by multiplying avogadros number by (2/31) Am I close? How many Ca^2+ ions do you have in 2.00 grams of calcium phosphate? I am getting 39, am i close? since there

    asked by Josh on August 5, 2009
  60. chemistry

    Inglês Português Espanhol For the determination of the quantity of chloride in a physiological serum sample by the Volhard method, a sample of 25.00 ml was treated with 50.00 ml of 0.110 mol/L Silver nitrate solution and the excess of silver ions was

    asked by william on October 3, 2017
  61. chemistry

    1.How many atoms are in a sample of copper with a mass of 18.46 grams? 2.How many formula units are in a sample of salt with a mass of 67.69 grams? 3.How many molecules are in a sample of water with a mass of 44.99 grams? 4.What is the mass in grams of

    asked by grace on February 6, 2011
  62. chemistry

    1.How many atoms are in a sample of copper with a mass of 18.46 grams? 2.How many formula units are in a sample of salt with a mass of 67.69 grams? 3.How many molecules are in a sample of water with a mass of 44.99 grams? 4.What is the mass in grams of

    asked by grace on February 6, 2011
  63. chemistry

    2.) If you pass 10.0mL of a 50.0mL solution of [Co(en)2Cl2]Cl that has been reduced with Zn through a cation exchange column, you will obtain a solution that has three H+ ions for every Co3+ ion that was originally present in the sample. These H+ ions are

    asked by xx on October 26, 2014
  64. Chemistry

    How many grams of Na2CO3 can be found in a 273 mL sample of 0.5 M solution

    asked by Linzy on April 8, 2013
  65. chemistry

    Write the compound formulas for each of the following pairs and the name of the compound formed when the elements or radicals combine. Mg+2 + OH-1 K+1 + PO4-3 Cu+2 + S-2 N+5 + O-2 Compounds have zero charge. Therefore, for magnesium hydroxide, the first

    asked by jessica on March 19, 2007
  66. chemistry

    An aqueous solution is analyzed and found to contain potassium ions and sulfite ions. Write the equation for the dissolution of the salt that produced this solution. If the solution contains 0.600 mol of potassium ions, how many moles of sulfite ions are

    asked by lebanon on February 23, 2014
  67. Science

    A scientist observed two rock samples. Sample A was found in the bottom of a dried-up lake and contained fossils. Sample B was found near a volcano and was glassy in appearance. Which statement is MOST LIKELY correct? A. Sample A is an igneous rock, and

    asked by maya on January 25, 2020
  68. AP Chemistry

    A mixture of aluminum and zinc metal is used in 2 experiments described below: A- A 1.7 gram sample of the mixture is reacted with excess hydrochloric acid and the resulting hydrogen gas is collected over water. The reaction takes place at 750 mm Hg

    asked by Kate on April 3, 2011
  69. chem

    "The percentage of sodium hydrogen carbonate, NaHCO3, in a powder for stomach upsets is found by titrating .275 M hydrochloric acid. if 15.5 mL of hydrochloric acid is required to react with .500 g of the sample, what is the percentage of sodium hydrogen

    asked by Dan on October 19, 2006
  70. chemistry

    Examine the information. Isotope B has a half-life of 3 days. A scientist measures out 100 grams of this substance. After 6 days has passed, the scientist reexamines the sample. How much of Isotope B will remain in the sample? 100 grams 63 grams 94 grams

    asked by PLEASE help on September 22, 2017
  71. Chemistry

    A 2.80-g sample of haematite ore containing Fe3+ ions was dissolved in a concentrated acid and the solution was diluted to 250 mL. A 25.0 mL aliquot was reduced with Sn2+ to form a solution of Fe2+ ions. This solution of Fe2+ ions required26.4mL of a

    asked by Luke on August 23, 2016
  72. Chem Help URGENT

    Could someone help me with these molecular formulas, i don't know what im doing wrong. For this example, i did it like this and it says its incorrect. Could you solve the the equations below your way and i match it to mines? Thank you so much Fe (s) +

    asked by Allison on October 28, 2010
  73. Chemistry

    A 10.0 mL sample of 3.00 M KOH(aq) is transferred to a 250.0 ml volumetric flask and diluted to the mark. It was found that 38.5 ml of this diluted solution was needed to react the stoichimetric point in a titration of 10.0 mL of a phosphoric acid, H3PO4,

    asked by Manpreet on December 7, 2017
  74. chem

    Which shows the greatest metallic character? -Na -K -Rb -Cs Also, What ions are very important for the proper functioning of biologic systems such as nerves and muscles? --oxygen ions --nitride ions --alkali metal ions --alkaline earth metal ions

    asked by DavidG on May 2, 2007
  75. Chemistry

    In a sample of solid Al(NO3)3, the ratio of aluminum ions to nitrate ions is (1) 1:1 (2) 1:2 (3) 1:3 (4) 1:6

    asked by Jazmin on October 25, 2010
  76. Chemistry/Engineering

    A 25 gram sample of CT is vaporized and used to fill a 5 L container. If the pressure in the container is 1.2 atm at 27 degrees Celsius, what is the molecular weight of CT in grams per mole? I used PV=nRT and found n=.2437 mol, but how do I got to grams

    asked by Becca on February 14, 2012
  77. chemistry

    If you pass 10.0mL of a 50.0mL solution of [Co(en)2Cl2]Cl that has been reduced with Zn through a cation exchange column, you will obtain a solution that has three H+ ions for every Co3+ ion that was originally present in the sample. These H+ ions are

    asked by xx on October 26, 2014
  78. chemistry

    If a sample of MgCl2 is known to contain 0.100 moles of Mg ions, how many moles of Cl ions are in the salt sample?

    asked by Laci on June 26, 2012
  79. Chemistry

    Calculate the mass in grams of the undiluted bleach that was in the sample of bleach titrated. Given: Density of undiluted bleach unkown is 1.042 g/mL. 14.44 mL of .100 M Na2S2O3. .0537 grams of NaClO. Each sample should conain 1/5 of the original

    asked by Kaitlin on October 26, 2014
  80. chemistry

    Determine the number of bromide ions in solution when 4.23 g of magnesium bromide and 1.21 g of potassium bromide are dissolved in 120mL of water. Please explain not sure how to even start this problem, thanks! chemistry - DrBob222, Wednesday, December 8,

    asked by Stacy on December 8, 2010
  81. CHEMISTRY

    1.) A water sample is found to have 9.0 ppb of chloroform,CHCL3. How many grams of CHCL3 would be found in a glassful (250 ML) of this water?

    asked by david on February 12, 2010
  82. chemistry

    A sample of 131 I was purified and then analyzed for iodine content. It was found that the sample was 99.8% pure. 25 hours later the sample was tested again and it was found that the sample was now just 78.2% pure. What is the half - life of 131 I?

    asked by zac on February 1, 2015
  83. UNO

    A blood sample contains several different types of cells, each of which contains different combinations of specific ions and molecules. The cells are suspended in water, and the water also contains many molecules and ions. Which term or terms could be used

    asked by henry on January 26, 2011
  84. chemistry

    Please help me through this problem... A 0.5117 gram fertilizer containing phsphorus was oven dried. The weight of the dried sample is 0.4998 grams. However, 10% moisture is still retained in the sample. Calculate the moisture content in the sample in as

    asked by smiley on August 31, 2007
  85. CALCULUS

    The masses of 10 books are found to be in an arithmetic sequence. If their total mass is 13 kg and the lightest book has a mass of 400 grams, what is the mass of the heaviest book? 2,000 grams 2,100 grams 2,200 grams 2,300 grams 2,700 grams

    asked by Chelsy on November 27, 2012
  86. English

    In your own opinion 1. How do objectives assist a student in completing the assignment? 2. Describe what needs to be done for the assignment found in a sample syllabus? 3. If you were to complete the assignment found in a sample syllabus, how would you set

    asked by Anonymous on June 17, 2018
  87. chem

    im studying for a test and i have no idea where to even start for this practice problem..?? a 0.15M(molarity im assuming)solution of BrCl2 contains.. a).15MBr2+ ions and .30M Cl- ions b).30MBr2+ ions and .15M Cl- ions c).15MBr2+ ions and .15M Cl- ions

    asked by hannah on March 27, 2011
  88. chem

    A 4.55L sample of water contains .115g of sodium ions. Determine the concentration of sodium ions in ppm if the density of the solutions is 1.00g/mL. Ok so ppm=mass of solute/mass of solution *10^-6 so we have the mass of the solute .115g and for the

    asked by natash on May 9, 2008
  89. chemistry

    When a reaction mixture with a total volume of 1750 mL that is 0.0263 M aqueous K+ was stoichiometrically produced as per the balanced equation, what volume (mL) of 0.0326 M aqueous K3PO4 was required? 3 BaBr2(aq) + 2 K3PO4(aq) → Ba3(PO4)2(s) + 6 KBr(aq)

    asked by eng on April 2, 2010
  90. chem

    how do I figure out the molecular formula for The concentration of lead (II) ions in a sample of polluted water that also contains nitrate ions is determined by adding solid sodium sulfate.

    asked by cindy on October 5, 2010
  91. science

    calculate how many grams of chloride ions are present in 50 grams of ocean salts

    asked by T-perry on April 17, 2013
  92. biology

    How many Calories are found in a food sample if burned in a calorimeter is raises the temperature of 1000 grams of water 58 degrees?

    asked by Anonymous on April 27, 2010
  93. chemistry

    What is the total sample size (in grams)for a sample of ethanol (CH3CH2OH) which contains 3.39 grams of oxygen?

    asked by Grace on September 22, 2010
  94. chemsitry

    What ions are very important for the proper fuctioning of biological systems such as nerves and cells? A)alkali earth metals B)hydrogen ions C)oxygen ions D)nitride ions E)alkali metal ions

    asked by ninjaturtle on April 21, 2007
  95. chem help ASAP!!!!

    What ions are very important for the proper fuctioning of biological systems such as nerves and cells? A)alkali earth metals B)hydrogen ions C)oxygen ions D)nitride ions E)alkali metal ions my choice is A or C can anyone help?

    asked by optifree on April 22, 2007
  96. chemistry

    A sample of a hydrate of CuSO4 with a mass of 250 grams was heated until all the water was removed. The sample was then weighed and found to have a mass of 160 grams. What is the formula for the hydrate? CuSO4 * 10 H2O CuSO4 * 7 H2O CuSO4 * 5 H2O CuSO4 * 2

    asked by cam on December 27, 2010
  97. mass

    A hard water sample contains 0.0081 %Ca by mass (in the form of Ca2+ ions)What mass of water in grams contains 1.3g of Ca? (1.3g of Ca is the recommended daily allowance of calcium for 19- to 24-year-olds.) Need help set this up?

    asked by Chemistry on April 19, 2015
  98. Physical Science

    1. Which equation correctly shows beta decay? (A) 210/82 Pb -> 209/81 Tl + 0/-1 e + y (B) 210/82 Pb -> 209/83 Bi + 0/-1 e + y (C) 210/82 Pb -> 210/83 Tl + 0/-1 e + y (D) 210/82 Pb -> 210/83 Bi + y (E) 210/82 Pb -> 210/83 Bi + 0/-1 e + y 2. The half-life if

    asked by CJ on November 18, 2013
  99. chemistry

    A 49.45 mL sample of solution containing Fe2+ ions is titrated with a 0.0103 M KMnO4 solution. It required 23.76 mL of KMnO4 solution to oxidize all the Fe2+ ions to Fe3+ by the following reaction. MnO4-(aq) + Fe2+(aq) Mn2+(aq) + Fe3+(aq) (unbalanced) (a)

    asked by Anonymous on October 28, 2010
  100. Ap chem

    If 200 ml of .300 molarity of silver nitrate are mixed with 350 ml of .500 molarity calcium chloride ions how many grams of percipitate are formed? How many moles of each ions are present?

    asked by Eman on November 6, 2012