Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

College Chemistry
Calculate the pH at the equivalence point in the titration of 55.0 mL of 0.180 M methylamine(Kb = 4.4 × 10−4) with 0.330 M HCl.

chemistry
What is the symbol equation of iron nails with copper sulfate solution.

Chemistry
25.0 g of potassium acetate (CH 3 COOK) are dissolved in 1.00 L of water. Calculate the pH of this solution. (PKa = 4.76 for CH3COOH)

Chemistry
What is the ratio of rate constants at 305k and 300k if the activation energy of a reaction is 58.3kJ/mol

chemistry
How do you rationalize an infrared spectrum of salicylic acid and aspirin? How do you know which is which?

Chemistry
What is the hydrogen ion concentration of a 0.22 M hypochlorous acid solution with Ka = 3.5E-8? The equation for the dissociation of hypochlorous acid is: HOCl(aq) = H+(aq) + OCl-(aq). I keep getting 3.60 as the concentration, but that is the wrong answer. Using ICE: Eq: HOCl...

chemistry
metals with 8-hydroxyquinoline, C9H7NO. After weighing the mixed precipitate, the precipitate is dissolved and the amount of 8-hydroxyquinoline determined by another method. In a typical analysis, a 127.3 mg sample of an alloy containing iron, manganese, and other metals was ...

chemistry
How do you rationalize an infrared spectrum of salicylic acid and aspirin? How do you know which is which?

chemistry
How many grams of NaHCO3 should be added to one liter of 0.100 M H2CO3 (Ka = 4.2 x 10-7) to prepare a buffer with pH = 7.00? I got molefrom.100/1L equal .100mole. where do I go from here?

Chemistry
a group of grade three students, along with their science teacher, were outside the classroom observing plant species. upon observation, the students recognized that some plant leaves were very pale yellow and weak looking while some looked healthy. suggest an appropriate ...

chemistry
What type of chemical reaction is this equation? CuO (s) + [2H+ + SO4 2-](aq) [Cu2+ + SO4 2-] (aq) + H2O (l)

Chemistry
A 152 g sample of ice at –37 degree C is heated until it turns into liquid water at 0 degree C. How do you find the change in heat content in the system? I've found H(I) [Change in heat of the ice] to be 11416.72 but im still stuck on the change of heat for the water.

chemistry
Use the table of complex ion formation constants to calculate the molar concentration of free Fe^2+ in 0.510M aqueous solution of potassium hexacyanoferrate(II) K4(Fe(CN)6) at 25 degrees celsius. I know the answer is 1.96*10^-6 m, but I'm at a loss on how to get there. I've ...

chemistry
the half time of a radioisotope is found to be 4.55 minutes. if the decay follow first order kinetics. what percentage of isotope will remain after 2.00 hours?

chemistry
Give the IUPAC name of thish hydrocarbon ch3ch2c(ch3)2ch2ch2ch2ch3

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 water?

Chemistry
What ratio of molar concentrations of sodium acetate to acetic acid can buffer a solution at a pH of 4.89?

Chemistry
Rank from longest to shortest bond length: Si-O, Si-H, Si-S

Chemistry
how many sigma and pi bonds in hooc-cooh

chemistry
How many grams of iron(II) oxalate dihydrate, Fe(C2O4)·2H2O,mass can be produced when a student begins the synthesis with 3.238 g of ammonium iron(II) disulfate hexahydrate, (NH4)2Fe(SO4)2·6H2O?

Chemistry
Which of the following liquids should be most soluble in water? A) CH3OH b) CH3CH2CH2CH2OH C) CH3CH2CH2CH2CH2CH3 D) CH3OCH3

Chemistry
An aqueous solution of ethyl alcohol is made by transfering 1.32 mL of liquid ethyl alcohol to a 50.0 mL volumetric flask, and then adding enough water to fill the flask to the mark. What is the volume/volume percentage of ethyl alcohol in the solution?

Chemistry
Based on the ratio of mean moles of O2/mol KClO3 what is the chemical equation for the reaction that occurred? Why? Is this conclusion in accord with the mass of the solid product that you obtained? Explain Moles of O2/mol KClO3 = 1.95x10^-2

Chemistry
Calculate the pH of a 1 L buffer solution that contains 0.050 moles of acetic acid and 0.040 moles of sodium acetate to which 0.020 moles of NaOH has been added.

Chemistry
Ka for a weak acid HA = 3.46x10^-8, calculate K for the reaction of HA with OH- HA + OH- = A- + H2O This is an equilibrium question, but I do not understand how to find the equilibrium constant K, from the equilibrium constant of an acid, Ka

Chemistry
How much heat does your body lose when 3.05 g of sweat evaporates from your skin at 25 ∘C? (Assume that the sweat is only water.) The heat of vaporization of water at 25 ∘C is 44.0 kJ/mole. Answer: 3.05g H2O*1mol/18.015gH2O= 0.169mol H2O 0.169mol*44.0kJ/1mol= 7.45kJ

Chemistry
indicate whether the following would increase decrease or have no effect on the solubility of copper (ii) carbonate (ksp - 2.5 x 10^-10) when compared to the solubility of water 1. dissolve it in an acidic solution 2. dissolve it in ammonia, forming a complex 3. dissolve it in...

Chemistry
If you had a 100 mL of 2.00 M HCl and you added 100 mL to it what is the final volume and final concentration? The volume would be 200ml, but would the concentration just stay the same?

Chemistry
Given H2(g) + (1/2)O2(g) ---> H2O(l), dH = -286 kJ/mol, determine the standard enthalpy change for the reaction 2h2O(l) ---> 2H2(g) + O2(g) 2H2O(l) ---> 2H2(g) + O2(g) H2(g) + (1/2) O29g) ---> H2O (l) : dH = -286 kJ/mols 2H2O(l) ---> 2H2(g) + 2O2(g) : would dH ...

Chemistry
Write the balanced chemical reaction (showing appropriate symbols and states) for the chemical reaction with enthalpy change equal to and defined by the quantity dHformation [NH3(g)] N2(g) + 3H2(g) --> 2NH3(g) Is that all the question is asking for?

Chemistry
When .560 g of Na(s) reacts with excess F2(g) to form NaF(s), 13.8 kJ of heat is evolved at standard-state conditions. What is the standard enthalpy of formation of NaF(s)? Start off by balancing the equation: 2Na(s) + F2(s) ---> 2NaF(s) Then make it for one mole Na(s) + (1...

Chemistry
The enthalpy of formation for a substance corresponds to the enthalpy change for a reaction. Write the specific chemical reaction defining the enthalpy of formation of butane: Just checking to make sure this is correct: 4C + 5H2 ---> C4H10

Chemistry
The following ions contain three oxygen atoms: A) carbonate, sulfite, and nitrite B) sulfite, nitrate, and bromate C) sulfate, hypochlorite, and carbonate D) chlorate, iodate, and phosphite I know I can eliminate A and C.

Chemistry
Calculate the amount of heat necessary to raise the temperature of 12.0 g of water from 15.4ºC to 93ºC. The specific heat of water = 4.18 J/gºC. q = ms∆T q = (12.0g) (4.18) (93.0 - 15.4) q = 3892.416 J ??

Chemistry
Potassium is a reactive element. Bromine is a reactive element. Write the complete balanced chemical equation using appropriate chemical symbols for the reaction when potassium reacts with bromine to make a solid product showing correct symbols and states of reactants and ...

Chemistry
Consider 1.00 L of the buffer system that contains 0.200 M hydrocyanic acid(HCN) and 0.150 M sodium cyanide (NaCN). The pKa of hydrocyanic acid is 9.31. What is the [HCN] after 0.020 mol of HCl is added?

chemistry
Write a comlete, balanced chemical equation for the reaction that occurs between aqueous iron(II) sulfate,FeSO4, and aqueous potassium hydroxide

Chemistry
A weather balloon is filled with helium that occupies a volume of 4.39 x 10^4 L at 0.995 atm and 32.0°C. After it is released, it rises to a location where the pressure is 0.720 atm and the temperature is -14.1°C. What is the volume of the balloon at that new location?

Chemistry
The enthalpy of combustion of benzoic acid (C6H5CO2H) is –3228 kJ/mol. The burning of 1.698 g of benzoic acid in a calorimeter causes the temperature to increase by 2.865 ºC. What is the heat capacity (in kJ/ºC) of the calorimeter?

Chemistry-Urgent
A gas at 61°C occupies a volume of 0.67 L. At what Celsius temperature will the volume increase to 1.12 L? whats the answer didn't understand

Chemistry
Given H2(g) + (1/2)O2(g) --> H2O, ∆Hº = -286 kJ/mol, determine the standard enthalpy change for the reaction 2H2O(l) --> 2H2(g) + O2(g). Just checking... should end up with ∆Hº = 572 kJ/mol right??

Chemistry
Given ∆Hºrxn = -1670 kJ/mol for 2Al(s) + (3/2)O2(g) --> Al2O3(s), determine ∆Hº for the reaction 2Al2O3(s) --> 4Al(s) + 3O2(g). I flipped Al(s) + (3/2)O2(g) --> Al2O3(s) to Al2O3(s) --> A(g) + (3/2)O2(s) and multiplied the molar values by 2. I ended up with...

Chemistry
Air trapped in a cylinder fitted with a piston occupies 163.1 mL at 1.08 atm pressure. What is the new volume when the piston is depressed, increasing the pressure by 25%?

Chemistry
The pressure of a sample of helium in a 3.40 L container is 0.988 atm. What is the new pressure if the sample is placed in a 2.15 L container?

Chemistry
A fixed amount of oxygen gas is held in a .500 L tank at a pressure of 4.09 atm. The tank is connected to an empty 1.50 L tank by a tube with a valve. After this valve has been opened and the oxygen is allowed to flow freely between the two tanks at a constant temperature, ...

Chemistry
If the thermometer reads 22 c and this corresponds to 19.8mmhg of water pressure , what is the pressure of a pure gas collected over water if the total pressure is 760 mmhg?next calculate the pressure of the gas and lets assume its hydrogen gas in atm. pressure of pure gas=760...

Chemistry
Which of the following processes is endothermic? a) H2O (g) --> H2O (l) b) 3O2 (g) + 2CH3OH(g) --> 2CO2(g) + 2H2O(g) c) H2O (s) --> H2O (l) d) O2(g) + 2H2(g) --> 2H2O(g) I a guessing b, since energy has to go into the reaction for water to go from a solid to a ...

Chemistry
Write the balanced chemical reaction (showing appropriate symbols and states) for the chemical reaction with enthalpy change equal to ΔHf° [NH3(g)]

Chemistry
The enthalpy of combustion of benzoic acid (C6H5CO2H) is -3228 kJ/mol. The burning of 1.698 g of benzoic acid in a calorimeter causes the temperature to increase by 2.865°C. What is the heat capacity (in kJ/°C) of the calorimeter?

chemistry
A gas sample occupies a container of 25.0 mL with a pressure of 125.1 kPa at room temperature (25.0 °C). The number of moles of this gas in the container is

chemistry
Calculate the thiocyanate concentration at equilibrium if the irone (III) ion concentration is 0.23 M and the complex ion concentration is 0.625 M t equilibrium. Keq= 138M^-1

Chemistry
Calculate the thiocyanate concentration at equilibrium if the irone (III) ion concentration is 0.23 M and the complex ion concentration is 0.625 M t equilibrium. Keq= 138M^-1

Chemistry
Calculate the thiocyanate concentration at equilibrium if the irone (III) ion concentration is 0.23 M and the complex ion concentration is 0.625 M t equilibrium. Keq= 138M^-1

chemistry
Could somebody tell me dose my answer for this question right or wrong for this question.My answer is reverse 2SO2(g) + O2(g) ↔ 2SO3(g) which has Kp = 3.45 x 106 at 600K. In an experiment, SO3 at pressure 125 atm is mixed with SO2 at pressure 0.13 atm and O2 at pressure 0....

Chemistry
A sample of sand initially at 22.3°C absorbs 1.34 x 10^3 J of heat. The final temperature of sand is 67.8 °C. What is the (in g) of sand in the sample? Round to the nearest whole number.

chemistry
The following information is given for ether, C2H5OC2H5, at 1atm: boiling point = 34.6 °C Hvap(34.6 °C) = 26.5 kJ/mol specific heat liquid = 2.32 J/g°C At a pressure of 1 atm,__kJ of heat are needed to vaporize a 25.1 g sample of liquid ether at its ...

chemistry
A fixed amount of oxygen gas is held in a .500 L tank at a pressure of 4.68 atm. The tank is connected to an empty 1.50 L tank by a tube with a valve. After this valve has been opened and the oxygen is allowed to flow freely between the two tanks at a constant temperature, ...

Chemistry
When .1625 g of Magnesium is burned in a bomb container that has a heat capacity of 3.03 kJ/ºC, the temperature increases by 1.252 ºC. How much heat (kJ/mol) is liberated during the burning of magnesium? Just want to make sure I am doing this correctly: q = ms∆T q = (....

Chemistry
Calculate the enthalpy of formation if 78.5 g of carbon dioxide in the following reaction: C(s) + H2O(g) --> CO2(g) Use the following equations: a) H2O(l) --> H2(g) + (1/2)O2(g): Δ°f = +285.8 kJ/mol b) C2H6(g) --> 2C(s) + 3H2(g): Δ°f = +84.7 kJ/mol c) 2CO2(g) + ...

Chemistry
In which of the following reactions is work done by the system to the surroundings? A) 2CH3OH(l) + 3O2(g) --> 4H2O(l) + 2CO2(g) B) S(s, rhombic) + O2(g) --> SO2(g) C) 2AgNO3(s) --> 2AgNO2(s) + O2(g) D)4Fe(s) + 3O2(g) --> 2Fe2O3(s) My guess is B because according to...

Chemistry
8) ( 1 point) What is the maximum number of grams PH₃ that can be formed when 3.4 g of phosphorus reacts with 4 grams of hydrogen to form PH₃? P₄ (g) +6H₂ (g) → 4PH₃ (g) * 3.7 g 6.8 g 45 g 270 g 10. Lead nitrate can be decomposed by heating. What is the percent ...

SCIENCE
WHAT IS MEAN OF CHEMISTRY?

Chemistry
A solution is prepared by pipetting 5.00 mL of 0.0983 molar HCl into a 100.0 mL graduated cylinder, and adding enough water to prepare 50.0 mL of solution. 1.The concentration of this solution is ____________M 2.The pH of this solution is ____________ Because HCl is a strong ...

chemISTRY
A hot lump of 33.2 g of copper at an initial temperature of 70.5 °C is placed in 50.0 mL of H2O initially at 25.0 °C and allowed to reach thermal equilibrium. What is the final temperature of the copper and water given that the specific heat of copper is 0.385 J/(g·°C)? ...

Chemistry
A 32.3 g iron rod, initially at 22.4 ∘C, is submerged into an unknown mass of water at 62.9 ∘C, in an insulated container. The final temperature of the mixture upon reaching thermal equilibrium is 59.4 ∘C.

Chemistry help!!
Calculate the concentration of a solution prepared by adding 15.00 mL of 2.10 X 10^-3 M KMnO4 from a buret into a 50.00 mL volumetric flask, which is then filled to the 50.00 mL graduation mark with distilled water.

Chemistry (Ochem)
I know that there is such thing as inversion of stereochemistry,but is there such thing as inversion of stereocenter? Are stereocenter and stereochemistry the same thing or mean the same thing? Thank you, Vivian

Chemistry
Which elements have the greatest tendency to behave as oxidizing agents? A) metals B) nonmetals I think the answer is B.

Chemistry
Write an equation for the half-reaction in which a potassium atom, K, is oxidized. A) K + e- ----> K+ B) K ----> K+ + e- C) K- ----> K+ + 2 e- I think A

Chemistry
Calculate the enthalpy of formation of carbon dioxide in the following reaction: C(s) + O2(g) -> CO2(g) Use the following equations: a) H2O(l) --> H2(g) + 1/2 O2(g): ΔH° = +285.8 kJ/mol b) C2H6(g) --> 2C(s) + 3H2(g): ΔH° = +84.7 kJ/mol c) 2CO2(g) + 3O2(g) --> ...

chemistry
calculate the heat of formation of methane given the heat of combustion of C,H2 and CH4 as-393,-285 and -887kj per mol respectively.

Chemistry
PbO2 + 2H2 = Pb + 2H2O If 478g of lead doixide is heated, what is: a. the number of moles of lead dioxide used? b. the number of moles of lead produced? c. the mass of lead produced? I am stuck.... please help!!

maths
3. Suppose a bookcase shelf has 5 Mathematics texts, 3 Biology texts, 6 Chemistry texts and 4 Physics texts. Find the number n of ways a student can choose: a. one of the texts; b. one of each type of text.

Chemistry
A store receives a shipment of defective balloons. Each has a tiny pinhole of the same size. If one balloon is filled with helium and another is filled with air to the same volume and pressure, which balloon will deflate faster and how much faster? The density of helium at ...

Chemistry
The molar mass of a compound is 92 g/mol. What is the molecular formula for a sample containing 0.606g Nitrogen and 1.390g Oxygen?

Chemistry
What is the limiting reactant is if 0.5gAl is reacted with 3.5gCuCl2? 2Al(s)+3CuCl2(aq) --> 3Cu(s)+2AlCl3(aq)

chemistry
what is the cell potential of the following cell: a platinum wire placed into a mixture of: KIO4 (0.02M), KIO3 (0.040M), H3PO4 (0.10M), KH2PO4 (0.40M) assuming it is put against a Ag/AgCl reference electrode?

chemistry
Calculate the molar mass of a gas if 4.40g occupies at 3.50 L at 560mmHg and 41 degrees celsisus

Chemistry
Refer to the table given for the ionic radii in your lab manual and approximate the attractive portion of the lattice energy for 1 mole of the following salts. (Consider only one bond if more than one bond exists.) a) Ca3P2 ___J b) MoCl4 ___J c) Cs2O ___J

Chemistry
what is the Mr of CO2? Use this to calculate the mass of co2 produced when 1kg of CaCO3 is heated.... (what are the answers?) MT!!!

Chemistry
Use the ion-electron method to write and balance the net ionic equation for each of the following reactions. MnO41- + Sn(OH)31- MnO2 + Sn(OH)62- in basic solution MnO41- + (COOH)2(aq) Mn2+ + CO2(g) in acidic solution I2(aq) + S2O32- I1- + S4O62- Zn(s) + HgO(s) ZnO(s) + Hg(l) ...

chemistry
60.0 g of iron that has an initial temperature of 250 degrees C and 60.0 g of gold that has an initial temperature of 45.0 degrees C are brought into contact with one another. Assuming no heat is lost to the surroundings, what will be the temperature when two metals reach ...

Chemistry
Determine the final temperature of water if 17.6 kJ of heat is added to 350 g of water initially at a temperature of 24.10 C. (specific heat of water is 4.184 Jg^-1K^-1)

chemistry
Calculate how many cm3 of 1M HCl is necessary to dissolve 1g of magnesium ribbon

chemistry
If you need to prepare 250.0 mL of a pH 5.00 buffer tha t has a total buffer concentration of acetic acid + sodium acetate of 0.050 M, how many moles of each will you need to prepare the solution? Given solutions of acetic acid and sodium acetate with concentrations of 0.10 M ...

Chemistry
carbon disulfide is prepared by heating sulfur and charcoal. the chemical equation is S2(g)+C(S)=CS2(g) and Kc = 9.4 at 900K. How many grams of CS2(g) can be prepared by heating 8.9moles of S2(g) with excess carbon in a 5.00L reaction vessel held at 900K until equilibrium is ...

Chemistry
I am having trouble getting the right answer for this question please help. Calculate Kc for the FeSCN2+ formation equilibrium [FeSCN2+] = 3.49x10^-5 M [Fe3+] = 4.39x10^-4 M [SCN-] = 1.93x10^-4 Kc = [FeSCN2+] / ([Fe3+]-[FeSCN2+]) * ([SCN-] - [FeSCN2+]) I keep getting 546.266 M...

chemistry
Suppose a balloon is filled so that its volume is 2.00 L when the pressure is 1.10 atm and the temperature is 300k. What volume will it occupy if it rises to an elevation where the pressure is 418mm Hg and the temperature is 200k?

Chemistry
A gas occupies 56.44 L at 2.00 atm and 310 K. If the gas is compressed to 23,520 mL and the temperature is lowered to 281 K, what is the new pressure in torr?

Chemistry
Of the compounds below,_____ has the smallest ionic separation and why? A.RbF B.K2S C.SrBr2 D.KF E.RbCl --> How does one determine if a compound has a high or low ionic separation, and what is ionic separation?

Chemistry
Of the compounds below,_____ has the smallest ionic separation and why? A.RbF B.K2S C.SrBr2 D.KF E.RbCl --> How does one determine if a compound has a high or low ionic separation, and what is ionic separation?

Chemistry
A 0.75 g sample of X2CO3 is dissolved in water and 80 mL of 0.20 M CaCl2 solution is added. This is the balanced equation I have created. X2CO3(aq) + CaCl2(aq) → CaCO3(s) + 2 XCl(aq) Based on the ratio in your balanced equation, how many moles of X2CO3 must have reacted? How...

chemistry
What equation is formed when HCl is titrated against Na2CO3 using methyl orange as indicator

Chemistry
A 1.50-g mixture of the solid salts Na2SO4(molar mass 142.04 g/mol) and Pb(NO3)2(molar mass 331.20 g/mol) forms an aqueous solution with the precipitation of PbSO4 molar mass 303.26 g mol The precipitate was filtered and dried, and its mass was determined to be 0.392 g.The ...

chemistry
20cm(cube) of a gaseous hydrocarbon were mixed with 90cm(cube) oxygen, and the mixture exploded. At room temperature, 60cm(cube) of gas were left. 40cm(cube) of the gas(cabon(4)oxide) were absorbed by sodium hydroxide, leaving 20cm(cube) of oxygen. find the empirical formular ...

chemistry
I need help. please show step by step? How many milliliters of 1.0 M NaOH would be required to completely neutralize 40.0 mL of 0.60 M HCl?

chemistry
6.10g of boron reacted completely with 22.9g of chlorine to give 29.0g of the metallic chloride. Calculate the empirical formula of the chloride.

Chemistry
A solution of boric acid (H3BO3) in water has a pH of 3.45. If the solution also contained NaHBO3, what do you expect to happen to the pH? Increase Decrease Stay the same Not enough information provided

Chemistry
A solution containing 10.50g aniline in 226g of benzene lowers the freezing point of benzene by 2.60°C. What is the molar mass of aniline? Thank you in advance

Chemistry
the freezing point of a water solution containing 26.1g of a non electrolyte in 538g of water is 0.73°C. what is the molar mass of the solute Thank you in advance

  1. Pages:
  2. <<Prev
  3. 1
  4. 2
  5. 3
  6. 4
  7. 5
  8. 6
  9. 7
  10. 8
  11. 9
  12. 10
  13. 11
  14. 12
  15. 13
  16. 14
  17. 15
  18. Next>>

Homework Help: Science