Popular questions and responses by Chemistry
  1. Enthalpy

    Consider the following reaction: 2 Mg + O2 → 2 MgO ΔH rxn = -1203 kJ Calculate the amount of heat (in kJ) associated with complete reaction of 4 moles of Mg. How do I set this up correctly?

    asked on April 18, 2015
  2. chemistry

    Consider a system consisting of a cylinder with a movable piston containing 10^6 gas molecules at 298K at a volume of 1L. Consider the following descriptions of this system: 1. Initial system 2. Starting from the initial system, the volume of the container

    asked on March 16, 2009
  3. Lauren

    Write the electron configuration of Sn and Sn2+ Give the electron configuration of Cu+ and Cu2+

    asked on November 14, 2007
  4. Lauren

    Which of the following has a standard enthalpy of formation value of zero at 25 degrees C and 1.0 atm A. Fe(s) B. Fe2O3(s) C. FeSO4(s) D. FeSO4(aq) E. FeS3(s) and what is enthalpy or how do you find it

    asked on November 16, 2007
  5. chemistry

    What is the lattice energy of NaBr? heat of formation of NaBr = -362 kJ/mol heat of sublimation for Na = 107.30 kJ/mol ionization energy for Na = 496 kJ/mol bond dissociation energy for Br2 = 190 kJ/mol electron affinity of Br = -325 kJ/mol heat of

    asked on December 4, 2010
  6. Equilibrium

    An equilibrium mixture of the following reaction was found to have [I2]= 0.0325M at 1200 ∘C. What is the concentration of I ? I2(g)⇌2I(g) Keq= 1.5×10−2 at 1200 ∘C Someone please help set this up?

    asked on May 5, 2015
  7. chemistry

    AlPO4(s)Al^3+(aq)+PO4^3-(aq) PO4^3-(aq)+H3O^+(aq)HPO4^2-(aq)+H2O(l) What is the net ionic equation for AlPO4(s) dissolving in H3O^+(aq)?

    asked on March 16, 2009
  8. Chem

    Hypobromous acid,HOBr, has acid -ionization constant of 2.5 X 10^-9 at 25 Celsius . What is the pOH of a 0.63 M HOBr solution? A4.40 B3.87 C5.20 D9.60 E10.13 I'm getting two answers between A or B

    asked on March 19, 2013
  9. Molarity

    A 4.0−L sample of a 6.3M NaCl solution is diluted to 50L . What is the molarity of the diluted solution? How would I set this up?

    asked on April 19, 2015
  10. Science

    2.40g of copper (ii)tetraoxosulphate(iv) crystals are prepared from 0.45g of copper (ii) oxide.the copper (ii) tetraoxosulphate(vi) crystals contain 0.45g of water of crystallisation.what mass of crystals and what is the mass of water of crystallisation

    asked on August 15, 2018
  11. Chemistry

    For preparing a set of standard solutions of FeNCS2+, the equilibrium molar concentration of FeNCS2+ is assumed to equal the initial molar concentration of the (SCN-) in the reaction mixture. why is this assumption valid?

    asked on September 17, 2017
  12. chemistry

    A 79.9-L sample of a gaseous hydrocarbon, measured at 1.00 atm pressure and 25.0°C, is burned in excess oxygen, liberating 4.24 × 10^3 kJ of heat at constant pressure. What is the identity of the hydrocarbon? (R = 0.0821 L · atm/(K · mol)) Substance

    asked on March 30, 2011
  13. Chemistry

    How many grams of sucrose are needed to make 875 mL of a 39.0% (w/v) sucrose solution?

    asked on January 27, 2013
  14. Carson

    What is the molecular geometry shape for H2GeO and is Sel2 polar or non polar. Thanks

    asked on May 14, 2019
  15. How many mole are there in 30g of calciumm chlorid

    How many mole are there in calcium chloride, CaCl2 (CaCl2=111).

    asked on February 5, 2017
  16. Chemistry

    Calculate the number of grams of xenon in 3.566 g of the compound xenon tetrafluoride.

    asked on February 5, 2014
  17. chem

    Excess fluorine, F2(g), reacts at 150°C with bromine, Br2(g), to give a compound BrFn. If 423 mL Br2(g) at 150°C and 748 mmHg produced 4.20 g BrFn, what is n? Predict the shape of this molecule using the VSEPR model.

    asked on December 13, 2010
  18. Freezing solution

    An ethylene glycol solution contains 26.2g of ethylene glycol (C2H6O2) in 81.4mL of water. Calculate the freezing point of the solution. (Assume a density of 1.00 g/mL for water.) how do I set this up?

    asked on April 27, 2015
  19. Chem

    in a 0.01 M solution of 1.4 butanedicarboxylic acid, (Ka1=2.9x10^-5, Ka2=5.3x10^-6), which species is present in the lowest concentration?

    asked on March 19, 2013
  20. Chemistry

    Ammonia has the formula NH3. Household ammonia is a dilute aqueous solution of NH3 . Aqueous ammonia is a base that can neutralize acids. If 18.4mL of 0.800 M HCl solution are needed to neutralize 5.00 mL of a household ammonia solution, what is the molar

    asked on February 11, 2009
  21. Lauren

    Use Lewis symbols to represent the electron transfer between the following atoms to give ions with noble gas configuations: A. Mg and S B. Ba and I

    asked on November 14, 2007
  22. 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 on April 19, 2015
  23. chemistry

    Alexandra decides to climb Mt. Krumpett, which is 5000 high. She determines that this will require a total of 3600 of energy for the trip. For her food supply, she decides to take nutrition bars. The label states that each bar contains 50 of carbohydrates,

    asked on February 6, 2013
  24. Chemistry

    The average human body contains 5.30L of blood with a Fe2+ concentration of 2.30×10−5M . If a person ingests 11.0mL of 15.0mM NaCN , what percentage of iron(II) in the blood would be sequestered by the cyanide ion?

    asked on March 14, 2009
  25. science

    ammonia is produced from the reaction of nitrogen and hydrogen according to the following balanced equation. N2+3H2g----- > 2NH3g. what is the maximum mass that can be produced from a mixture of 2.00×10³gN and 8.00×10⁴H2?

    asked on June 21, 2019
  26. Chem

    What is the equilibrium concentration of chloroacetic acid in a solution prepared by dissolving 0.0314 mil of chloroacetic acid in 1.10L of water? For chloroacetic acid, Ka= 1.4X10^-3

    asked on March 19, 2013
  27. science

    the teacher instructed three students A,B,and C respectively to prepare a 50% (mass by volume) solution of sodium hydroxide (NaOH). 'A' dissolved 50 g of NaOH in 100 ml of water B dissolved 50g of NaOH in 100g of water while C dissolved 50g of NaOH in

    asked on September 6, 2011
  28. Chemistry

    Given the equation C3H8+5O2->3CO2+4H2O. 1.)Suppose 1.5 moles of C3H8 will be used, How many moles of H2O and CO2 will be formed? 2.)what volumes (at STP) of O2 and CO2 are involved?

    asked on August 24, 2017
  29. Heat

    Consider the following equation: CO + 2 H2 → CH3OH ΔH rxn = -128 kJ Calculate the amount of heat (in kJ) associated with complete reaction of 8.08 g H2. How would u set that up?

    asked on April 18, 2015
  30. Chemistry

    Calculate the formula mass for each of the following halogen compounds to five or more significant figures:? bake asked 5 months ago (a) NaIO3 (antiseptic) (b) CCl2F2 (former refrigerant)

    asked on February 5, 2014
  31. Abby

    If you have 320.0 mL of water at 25.00 °C and add 140.0 mL of water at 95.00 °C, what is the final temperature of the mixture? Use 1.00 g/mL as the density of water.

    asked on December 5, 2013
  32. Chemistry

    Calculate DeltaHrxn for the following reaction: C + H2O --> CO + H2 Use the following: C + O2 --> CO2 DeltaH = -393.5 kJ 2CO + O2 --> 2CO2 DeltaH = -566.0 kJ 2H2 + O2 --> 2H2O Delta H = -483.6 kJ DeltaHrxn = ?

    asked on March 20, 2012
  33. chemistry

    CH3 CH3-C-CH3 CH3CH2CH2-C-CH2CH2CH2CH3 CH3 give the IUPAc name for this compound? is it 4-methyl-4-tert-methyloctane?

    asked on March 5, 2010
  34. ChemChem

    Hi, please help! Question: Farmers added Calcium hydroxide to soil one morning. They then planned to add Ammonium chloride fertilisers to the soil immediately. However, the instruction label on the packet of fertilisers read: "Do not add fertiliser

    asked on November 2, 2009
  35. Chemistry

    Vitamin B12, cyanocobalamin, is essential for human nutrition. It is concentrated in animal tissue but not in higher plants. Although nutritional requirements for the vitamin are quite low, people who abstain completely from animal products may develop a

    asked on September 13, 2009
  36. Sara

    How many mL of .200M acetic acid are mixed with 13.2mL of.200M sodium acetqte to give a buffer with pH=4.2

    asked on August 9, 2009
  37. Jake

    If 142.38 g of l water at 21.7 degrees C is placed into a syrofoam cup with 174.36 g of ice at -27.5 degrees C what would be the final temperature of the entire contents at equilibrium? If it is partially frozen, how many g of the ice has melted? given

    asked on October 16, 2007
  38. Chemistry

    A certain mine produces 2.5 108 kg of copper from chalcopyrite (CuFeS2) each year. The ore contains only 0.80% Cu by mass. (a) If the density of the ore is 2.0 g/cm3, calculate the volume of ore removed each year. (b) Calculate the mass of SO2 produced by

    asked on April 13, 2007
  39. Chemistry

    1.) For the reaction: 2 HBr + H2SO4 --> Br2 + SO2 + 2 H2O : if you start with 5.00 g of each reactant and end up with 5.00 g of bromine, what is the percent yield? 98.8% 2.0% 101.2% 100.0% 2.) For the reaction: 2 HBr + H2SO4 --> Br2 + SO2 + 2 H2O : if you

    asked on November 10, 2018
  40. ryancon

    The half-life of rubidium-87 (natural absorbance 27.83%) is 5.1x10^11 years. What mass of rubidium is present if an average sample decay rate of 35.0 disint./sec is detected? I've already converted years to seconds but not sure what to do after..

    asked on November 4, 2018
  41. science

    how many grams of nacl are required to neutralize 100 ml of 1M h2so4???

    asked on March 15, 2017
  42. Chemistry

    NaCl [Symbol] Na + Cl2 Type of reaction: synthesis KOH + HNO3 [Symbol] HOH + KNO3 Type of reaction: double replacement Ca + S [Symbol] CaS Type of reaction: synthesis BaBr2 + Cl2 [Symbol] BaCl2 + Br2 Type of reaction: Cs2 + H2O [Symbol] CsOH + H2 Type of

    asked on January 3, 2017
  43. May

    Based on the data in this table, what would be the value of k at 795 K? T k 625 1.1 x 10^-4 635 1.5 x 10^-4 645 2.0 x 10^-4 I tried to figure it out using two different ways, and I got 7.3 x 10^-3 both times. I asked for a "hint" and the homework site told

    asked on February 1, 2016
  44. Equilibrium constant

    Consider the reaction: SO2Cl2(g)⇌SO2(g)+Cl2(g) A solution is made containing initial [SO2Cl2]= 0.022M . At equilibrium, [Cl2]= 1.7×10−2M Calculate the value of the equilibrium constant.

    asked on May 5, 2015
  45. pressure

    What is the pressure in millimeters of mercury of 0.0140mol of helium gas with a volume of 222mL at a temperature of 30∘C?

    asked on April 29, 2015
  46. Pressure

    Aerosol cans carry clear warnings against incineration because of the high pressures that can develop upon heating. Suppose a can contains a residual amount of gas at a pressure of 750mmHg and a temperature of 23∘C. What would the pressure be if the can

    asked on April 29, 2015
  47. Freezing point

    How many moles of each of the following are needed to give the same freezing point lowering as 5.0mol of the nonelectrolyte ethylene glycol in 1 kg of water?CH3−OH, a non electrolyte, KNO3, a strong electrolyte. Im confused on what they are asking, and

    asked on April 28, 2015
  48. Metals

    Transition metals (also called heavy metals) form insoluble compounds with hydroxide ions. Therefore, it is possible to extract heavy metal ions from water by raising the pH. The precipitation reaction between cadmium(II) and hydroxide is shown below.

    asked on April 19, 2015
  49. Chemical Reactions

    How can i get the step by step procedure for a chemical reaction? For example: the step by step procedure for the synthesis reaction of ammonia

    asked on April 12, 2015
  50. Chemistry

    A sample of toluene, C7H8 has a mass of 74.5 g. a) how many molecules does the sample contain? b) How many carbon atoms does it contain? How many hydrogen atoms does it contain? My work For b would it be 7 carbon atoms and 8 hydrogen atoms

    asked on November 24, 2014

    Method for getting correct answer? Thank you! The reaction below is an endothermic reaction. What would one have to do to shift the equilibrium to the right? SO2Cl2(g)↔SO2(g) + Cl2(g) a. Decrease the temperature b. Increase the temperature c. Remove some

    asked on April 6, 2014
  52. Chemistry

    Electron exhibiting a particle wavelength of 5.2 x 10-9 are emitted from hydrogen atoms after interaction with high energy photons. Assuming that the electrons in the hydrogen atom were in their ground state prior to interaction, determine the wavelength

    asked on October 13, 2013
  53. Idontgetit

    The value of the equilibrium constant, Kc, at a certain temperature is 8.33 x 10-4. Would the reaction as represented by the chemical equation favor reactants or products? Enter P or R. Cl2CO(g) = CO(g)+Cl2(g)

    asked on October 2, 2013
  54. Idontgetit

    The value of the equilibrium constant, Kc, at a certain temperature is 2.56 x 10-1. If the reaction quotient for a mixture of these species at the same temperature is found to be 9.90 x 10-4, would the mixture yield more products, more reactants or is it

    asked on October 2, 2013
  55. Idontgetit

    The value of the equilibrium constant, Kc, at a certain temperature is 2.50 x 102. If the reaction quotient for a mixture of these species at the same temperature is found to be 7.37 x 100, would the mixture yield more products, more reactants or is it at

    asked on October 2, 2013
  56. Idontgetit

    The value of the equilibrium constant, Kc, at a certain temperature is 2.56 x 10-1. If the reaction quotient for a mixture of these species at the same temperature is found to be 9.90 x 10-4, would the mixture yield more products, more reactants or is it

    asked on October 2, 2013
  57. Chemistry

    the hydronium ion concentration of a 0.050 M solution of a weak acid is 5.9 X 10^-3 M. the acid-dissociation constant is 1.37 X 10^-4 at 25 celsius. what is the pH of this solution? A. 0.077 B. 1.30 C. 2.23 D. 3.86 E. 5.13

    asked on March 18, 2013
  58. Chemistry

    A solution of AuCl- is mixed with a solution of Sn2+ under standard conditions. What is the equation? the answer is 2AuCl4- + 3Sn2+ -> 3Sn4+ + 2Au + 8Cl- how do i get this? ITS desperate... plz help me! THANK_YOU SO MUCH!

    asked on June 14, 2012
  59. Chemistry

    What volume of 0.250M KOH is required to titrate 2.30 x 10^3 mol of the weak acid H2C2O4 ? I know the answer is 18.4, but can you show the process?

    asked on June 14, 2012
  60. chemhelp

    is LiCl toxic?

    asked on January 24, 2012
  61. Shawn

    How many milliliters of 0.355 M NaF solution are needed to react completely with 24.6 mL of 0.216 M CaCl2 solution? How many grams of CaF2 will be formed? The reaction is CaCl2(aq) + 2NaF(aq) → CaF2(s) + 2NaCl(aq)

    asked on July 8, 2011
  62. CHEM

    What is the number of "UNBOUND" electrons in H2O...its not 0 or it 1??

    asked on April 30, 2011
  63. kassie

    What is the major product of the reaction between methanol and (2R,3S)-2-bromo-3-methylpentane at room temperature?

    asked on February 7, 2011
  64. chemistry

    Given the reaction 3C(s) + 4H2(g) + 5O2(g) ---> 3CO2(g) + 4H2O(l) ÄH= -2323.7 kJ How much heat would be released when 34.1 g of H2 react?

    asked on December 3, 2010
  65. muah

    using only words and no numbers how would i explain the steps necesarry to show how many kilograms are in a milligram? thanks :D

    asked on September 26, 2010
  66. muah

    explain why the name of the insect millipede doesnt follow SI conventions? please help me i cant find this any where in my text. I would be very happy if you did help. :D

    asked on September 26, 2010
  67. chemistry

    The reaction converting glycerol to glycerol-3-phosphate is energetically unfavorable by 9.2kJ. The reaction of ATP with water to yield ADP, hydrogen phosphate ion, and hydrogen ion is energetically favorable by 30.5kJ. These reactions are coupled so that

    asked on March 19, 2009
  68. REETA

    A 2.10 mol sample of oxygen gas is confined to a 5.10 L vessel at a pressure of 7.99 atm. Find the average translational kinetic energy of an oxygen molecule under these conditions in (j/mol) When i was working this out i tried using pv=nrt to find the

    asked on October 21, 2008
  69. Lauren

    The specific heat of water is at 4.184J/g * degree C. How much heat is evolved, or absorbed, when the temperature of 9.00 mol of liquid water cools from 38 degrees C to 28 degrees C? How do I start this problem

    asked on November 16, 2007
  70. Suzy

    Can some one read my lab report for me... I have it almost finished.. I just need help on the discussion part Please

    asked on November 16, 2007
  71. Jake

    A combustion bomb containing 5.417 g of aluminum metal and 15.974 g of iron III oxide is placed in an ice calorimeter that initially contained 7.746 kg of ice (at o degrees C) and 7.894 kg of liquid water (at o degrees C). The reaction, once ignited by

    asked on October 16, 2007
  72. Jim

    I need some help with calculating percent yield and percent purity of aspirin. Here's my data (questions follow): SYNTHESIS Mass of salicylic acid.., 2.0 g Volume of acetic anhydride.., 5 mL Mass of watch glass.., 22.10 g Mass of aspirin and watch glass..,

    asked on March 24, 2007
  73. chemistry

    what would be the e configuration for sodium- 23 (up and down arrows) 1s- ? arrows 2s- ? arrows 2p- ? arrows 3s- ? arrows 3p- ? arrows

    asked on February 27, 2020
  74. chemistry

    How much heat is required to take 4 kg of water from 20◦C to near boiling at 99◦C? Answer in units of J. I got 1320.88?

    asked on October 6, 2019
  75. Science

    What is the balance equation of decane

    asked on September 9, 2019
  76. Science

    Ammonia is produced from the reaction of nitrogen to the following balanced equation N2+3H2-2NH3

    asked on June 22, 2019
  77. science

    1:when 20.0ml of 1.7m AgN03 added to grammar of AgCL will be produced? 2:if the percentage yield is 30%,calculate the actual yield.

    asked on June 21, 2019
  78. chemistry

    what is the source of activation energy in an exothermic reaction? Is an example heat?

    asked on April 3, 2018
  79. Chemistry

    The molecules present in 5.2gms of glucose will be c6h12o6

    asked on February 15, 2018

    Heat of Combustion of paraffin wax Initial mass of candle 40.3g Mass of tin calorimeter 41.1g Mass of half-filled calorimeter with water 220.4g Initial temp of water 18.8°C Final temp of water 26.6°C Final mass of candle 38.2g Calculate heat of

    asked on September 9, 2017
  81. Chemistry

    How to prepare 10% sucrose solution enriched with 0.1% phenylalanine? And also how to make the stock solution of phenylalanine for the above process. I have prepared 10% sucrose solution by adding 10g sucrose in 100ml water , but how do i make 0.1%

    asked on June 24, 2017
  82. Chemistry

    Neutralization of water containing H2SO4 and HNO3 with CaSO3. What is the pH in water if the volume is 1000 liter and the concentration of H2SO4 is 0,0013 M and concentration of H2SO4 is 0,0010 M ? And how much of CaCO3 is needed for neutralization of the

    asked on March 28, 2017
  83. chemistry

    CH3-C(triple bond)C-CH-(C2H5)CH3product a and product b

    asked on December 19, 2016
  84. chemistry

    CH3-C(triple bond)C-CH-C2H5-CH3product a and product b

    asked on December 19, 2016
  85. Science

    Calculate the gram molecular mass of nitrogen if 360cc at STP weigh 0.45g.

    asked on November 24, 2016
  86. Chemistry

    Why was etching needed to bring out the grain boundaries? My answer: Is it for the light to bounce back?

    asked on October 17, 2016
  87. Chemistry 12th

    How can you prepared to benzo phenol from phenyl magnetium bromide

    asked on July 29, 2016
  88. Kris

    A gas mixture containing 0.400 mol He, 0.184 mol CH4 and 0.0374 mol Ne was placed in a 3.00-L flask at 301 K. What is the PRESSURE (atm) in the flask?

    asked on April 3, 2016
  89. HOFBrINCl

    can someone help me on these 2 questions so i can get an idea to do the rest of mine. im given hydrochloric acid and a marble chip (calcium carbonate i think), so what would be the reactants, the word equation, the balanced equation, prediction of type of

    asked on March 15, 2016
  90. for solubility

    How match water make in 0.123 N NaoH for 0.1 N NaoH

    asked on January 24, 2016
  91. georgia

    what is a solubility rate?

    asked on August 26, 2015
  92. caley

    A solution contains 2.0 × 10^–3 M Ba^2+ and 1.0 × 10^–2 M Sc^3+. A source of F^– is slowly added to the solution. Will BaF2 (Ksp = 1.84 × 10^–7) or ScF3 (Ksp = 5.81 × 10^–24) precipitate first? I believe that ScF3 would precipitate first but

    asked on May 19, 2015
  93. Volume

    Imagine that you have an ideal gas in a 7.00L container, and that 1050 molecules of this gas collide with a square-inch area of the container at any given instant. If the volume is increased to 56.0L at constant temperature, how many collisions will occur

    asked on April 30, 2015
  94. Molar mass

    A sample of gas has a mass of 0.580g . Its volume is 119mL at a temperature of 80∘C and a pressure of 743mmHg . Find the molar mass of the gas. I think I got a step wrong in the problem, please help?

    asked on April 29, 2015
  95. Moles

    How many moles of each of the following are needed to give the same freezing point lowering as 5.0mol of the nonelectrolyte ethylene glycol in 1 kg of waterCH3−OH, a non electrolyte,KNO3, a strong electrolyte I am so lost with what they exactly want for

    asked on April 27, 2015
  96. Molarity

    A 44.8−mL sample of a 7.0M KNO3 solution is diluted to 1.10L What volume of the diluted solution contains 16.0g of KNO3? Would I do the same thing for this one or would does it have an extra step it it.

    asked on April 19, 2015
  97. newsome

    1. lactate has a molecular weight of 90.08. How much lactate is needed to make 3 liters of .15 molar lactate. 2.What is the percentage of lactate (it's a solid) in the solution made in question 1.

    asked on November 13, 2014
  98. Jade

    1. Spectroscopic studies of the reaction of azide ion with the cluster [Ru3(CO)12] in acetone solvent confirmed the occurrence of process (i) under a CO atmosphere. Kinetic measurements of this rapid [Ru3(CO)12]+ N3– →[Ru3(NCO)(CO)11]–+ N2(i)

    asked on July 25, 2014
  99. Chemistry

    Calculate the volume of 2.00 M solution of KOH that is required to neutralize 30.0 mL of 1.00 M solution of HNO3.

    asked on May 6, 2014
  100. chemistry

    Find the Qsp when 5 mL of 0.17 M K2 CO3 (aq) and 1 L of 0.013 M AgNO3(aq) are mixed together. The solubility product of Ag2CO3 is 6.2 × 10−12

    asked on April 21, 2014


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