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April 30, 2016

Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

Chemistry
Calculate the pressure in an evacuated 250mL container at 0 degrees C when the O2 in 1.00 cm^3 of liquid oxygen evaporates. Liquid oxygen has a density of 1.118 g/cm^3.
Tuesday, November 17, 2015 by Sarah

Chemistry
A solution contains 0.50M Nh3 and 1.50 M Nh4cl. What is the maximum concentration of mg2+ that can be present in such a solution without precipitating Mg(oh)2?
Tuesday, November 17, 2015 by Angel

Chemistry
A block of copper of unknown mass has an initial temperature of 69.1 ∘C . The copper is immersed in a beaker containing 93.4 g of water at 21.0 ∘C . When the two substances reach thermal equilibrium, the final temperature is 24.2 ∘C . Find mass of Copper
Tuesday, November 17, 2015 by Judy Blue

Chemistry
Calculate the pH during the titration of 40 ml of 0.1000 M HCl with 0.1000 M NaOH solution after the following additions of base: A.) 28.00 ML B.) 39.80 ML C.) 48.00 ML
Tuesday, November 17, 2015 by Braden

Chemistry
Fuel values, reported in units of KJ/g, are useful in comparing the efficiency of various energy sources on a mass basis. Determine the fuel value of the glucose and the tristearin. Which one, carbohydrates or fats, have the highest fuel value (and hence is the most efficient ...
Tuesday, November 17, 2015 by Anonymous

chemistry
I know everyone guessed i had a few more i couldnt do. Sorry but assistance please: 1.Sucralfate (molecular weight: 2087g/mol) is a major component of Carafate® which is prescribed for the treatment of gastrointestinal ulcers. The recommended dose for a duodenal ulcer is ...
Tuesday, November 17, 2015 by mikey

Chemistry (Help)
Calculate the DHrxn of C57H110O6 (s) + O2(g) --> CO2(g) + H2O(l) with DHf. C57H110O6(s) -390.70 O2(g) 0 CO2(g) -393.5 H2O(l) -285.840 I balanced the equation: 2C57H110O6 (s) + 163O2(g) --> 114CO2(g) + 110H2O(l) and my work: DHrxn = [224mol(-393.5+(-285.840))] - [165mol(-...
Tuesday, November 17, 2015 by Anonymous

Chemistry (Check)
Calculate the DHrxn of C6H12O6 (s) + O2 (g) --> CO2 (g) + H2O (l) with DHf. C6H12O6(s) -1260.04 O2(g) 0 CO2(g) -393.5 H2O(l) -285.840 I balanced the equation: C6H12O6 (s) + 6O2 (g) --> 6CO2 (g) + 6H2O (l) and my work: DHrxn = [12mol(-393.5+(-285.840))] - [7mol(-1260.04+0...
Tuesday, November 17, 2015 by Anonymous

chemistry
41. Ethyne, C2H2, used in welding react with oxygen as shown below.
Tuesday, November 17, 2015 by mark

chemistry
i am working on a practice worksheet and need help with a few i can not understand. please and thank you. I have to post them separately sorry 49.how many grams of water are needed to completely hydrolyze 30.8 g of the ester? A.0.416 g B.30.8 g C.11.3 g D.7.49 g 54. Sodium ...
Tuesday, November 17, 2015 by mark

Chemistry
al(i) Determine the number of moles of Ca2+ present in the titrated sample. (ii) Determine the [Ca2+] and hence the solubility of CaSO4.2H2O in the original 10.0 mL sample. so
Tuesday, November 17, 2015 by Mara

Chemistry
A 10.0 mL sample of supernatant liquid from the system described by equation 1 was titrated with 0.01022 M EDTA solution to an end-point at 16.90 mL. Titration of the blank gave a titre (end-point) at 1.45 mL. Determine the titration volume required to titrate the Ca2+ alone.
Tuesday, November 17, 2015 by Mara

CHEMISTRY
An analysis of a compound gave 40% carbon 3.7% hydrogen. the vapour density of the compound is 30. calculate the empirical and molecula fomular.
Tuesday, November 17, 2015 by NEMUEL

chemistry
How many milliliters of water has been dispensed if the initial buret reading was 0.45 mL and the final is 20.33 mL?
Tuesday, November 17, 2015 by Anonymous

chemistry
how many grams of NaCl should be added in 15ml which must have a final concentration of 10mM
Tuesday, November 17, 2015 by Josh

Chemistry
Describe an experiment using only hot and cold water that would allow you to verify that the heat capacity of a coffee-cup calorimeter is about 1.0x10^1 J/oC. Be specific.
Tuesday, November 17, 2015 by Wex

Chemistry
Experimental results for hydrochloric acid (neutralization) are always a little less negative than the usual constant of heat of neutralization for strong acids and bases (-57.35kJ). Suggest reasons for this.
Tuesday, November 17, 2015 by Wex

chemistry
anyone know how to do this and which choice is correct?thank you so much in advance. Use the Henderson-Hasselbalch equation to calculate the pH of a buffer that is 0.350 M acetic acid and 0.250 M sodium acetate. a.4.89 b.4.47 c.4.59 d.none of the above is is not 4.74
Tuesday, November 17, 2015 by anna

chemistry
The following reaction can be written as the sum of two reactions, one of which relates to ionization energy and one of which relates to electron affinity: Li(g)+F(g)→Li+(g)+F−(g) What is the reaction that corresponds to the first ionization energy of lithium, Li? ...
Monday, November 16, 2015 by rabia

Chemistry
Ice has negative caloric count. How much energy, in each of the following units, does your body lose from melting 175g of ice? Express your answers in J, kJ, cal, Cal
Monday, November 16, 2015 by Nicole

Chemistry (Check)
Calculate the DHrxn of C57H110O6 (s) + O2(g) --> CO2(g) + H2O(l) with DHf. C57H110O6(s) -390.70 O2(g) 0 CO2(g) -393.5 H2O(l) -285.840 I balanced the equation and my work: DHrxn = [224mol(-393.5+(-285.840))] - [165mol(-390.70+0)] = -87706.66 KJ/mol Is this right? If not, ...
Monday, November 16, 2015 by Anonymous

Chemistry (Check)
Calculate the DHrxn of C6H12O6 (s) + O2 (g) --> CO2 (g) + H2O (l) with DHf. C6H12O6(s) -1260.04 O2(g) 0 CO2(g) -393.5 H2O(l) -285.840 I balanced the equation and my work: DHrxn = [14mol(-393.5+(-285.840))] - [7mol(-1260.04+0)] = -690.48 KJ/mol Is this right? If not, what ...
Monday, November 16, 2015 by Anonymous

Chemistry
Determined at which temperature is the solubility of KNO3 at 60 grams per 100 grams of water
Monday, November 16, 2015 by Tommy

Chemistry (Check)
The bond strengths of the compounds HF, HCl, HBr, and HI are as follows: compound bond strength, kJ/mol HF 569.87 HCl 431.62 HBr 366.35 HI 298.407 Briefly explain why the bond strengths are ranked in this order. My guess is: They are ranked in this order because of the ...
Monday, November 16, 2015 by Anonymous

Chemistry
What is the concentration of lead ions in a solution if they are completely precipitated from 36.3 mL of solution by 29.6 mL of 0.35M potassium iodide.
Monday, November 16, 2015 by Sam

chemistry
Determine the mass of copper that has the same number of atoms as there are in 15.46 mg of gold. Answer in units of mg.
Monday, November 16, 2015 by Quinton

chemistry
Determine the quantity (g) of pure CaCl2 in 7.5 g of CaCl2*9H2O
Monday, November 16, 2015 by ali

Chemistry
A 22.6 mL sample of a weak monoprotic acid, HX, requires 50.0 mL of 0.050 M NaOH to reach the equivalence point. After the addition of 30.0 mL of NaOH, the pH is 4.90. What is the Ka of HX?
Monday, November 16, 2015 by Lexi

chemistry
at 25 celcius, how many dissociated OH ions are there in 8.0x10^-1 L of aqueous solution with pH 4.73?
Monday, November 16, 2015 by Christine

Chemistry
Explain what would happen if a saturated solution of kno3 at 50°c is heated
Monday, November 16, 2015 by Miya pierre

Chemistry
2.0 gram of C2H4 is reacted withO2. What mass of water is produced?
Monday, November 16, 2015 by Cindy

chemistry
Which is the correct expression for Keq when the chemical reaction is as follows: N2 + 3H2 2NH3.
Monday, November 16, 2015 by luis

Chemistry
How do I know the order of placing dots on the lewis structure? Please give an example.
Monday, November 16, 2015 by Rucha

Chemistry
State the kind of intermolecular forces that would occur between the solute and solvent in barium nitrate (ionic). Check all that apply. ion-dipole hydrogen bonding dispersion dipole-dipole
Monday, November 16, 2015 by Desiree Torres

Analytical Chemistry
I have a 0.00156 M solution of CuSO4*5H2O in water (from 0.0398 g of CuSO4*5H20 in 100 mL of water). How would I calculate the ppm of Cu of that solution from that information? Now if I were to find ppm of Cu in different aliquots of this stock solution (5 mL, 10 mL, etc.) how...
Monday, November 16, 2015 by Ronnie

Chemistry
Experimental results for hydrochloric acid (neutralization) are always a little less negative than the usual constant (-57.35kJ). Suggest reasons for this.
Monday, November 16, 2015 by Wex

chemistry
What is the value of the equilibrium constant at 500 °C for the formation of NH 3 according to the following equation? N 2 ( g ) + 3H 2 ( g ) ⇌ 2NH 3 ( g ) An equilibrium mixture of NH 3 ( g ), H 2 ( g ), and N 2 ( g ) at 500 °C was found to contain 1.35 M H 2 , ...
Monday, November 16, 2015 by mayuri

chemistry
A reaction is represented by this equation: 2W( aq ) ⇌ X( aq ) + 2Y( aq ) K c = 5 × 10 −4 (a) Write the mathematical expression for the equilibrium constant. (b) Using concentrations of ≤1 M , make up two sets of concentrations that describe a mixture ...
Monday, November 16, 2015 by mayuri

chemistry
A reaction is represented by this equation: 2W( aq ) ⇌ X( aq ) + 2Y( aq ) K c = 5 × 10 −4 (a) Write the mathematical expression for the equilibrium constant. (b) Using concentrations of ≤1 M , make up two sets of concentrations that describe a mixture ...
Monday, November 16, 2015 by mayuri

Chemistry
Hydrocarbon burn in excess oxygen yields 4.4g of carbon(iv)oxide and 2 of 7g of water. Find the empirical formula of hydrocarbon
Monday, November 16, 2015 by Prudent

chemistry
0.60g of a gaseous hydrocarbon E when completely burnt in oxygen gave 1.76g of carbon dioxide. WHAT IS THE EMPIRICAL FORMULA OF E?
Monday, November 16, 2015 by viky

Science: Chemistry
How many kilojoules are released when 115 g of Si reacts with chlorine? Si(s)+2Cl2(g)→SiCl4(g)ΔH=W​22;657kJ
Sunday, November 15, 2015 by Alex

Science: Chemistry
Pentane (C5H12) burns in oxygen to produce carbon dioxide and water. C5H12(g)+8O2(g)→5CO2(g)+6H2O(g) Calculate the mass of CO2 that can be produced if the reaction of 38.5 g of pentane and sufficient oxygen has a 58.0 % yield.
Sunday, November 15, 2015 by Alex

Chemistry
A 0.120 g sample of a diprotic acid of unknown molar mass is dissolved in water and titrated with 0.1218 M NaOH. The equivalence point is reached after adding 12.4 mL of base. What is the molar mass of the unknown substance?
Sunday, November 15, 2015 by Jorge

chemistry Dr BOB
In many residential water systems, the aqueous Fe3+ concentration is high enough to stain sinks and turn drinking water light brown. The iron content is analyzed by first reducing the Fe3+ to Fe2+ and then titrating with MnO4- in acidic solution. Fe2+(aq) + MnO4-(aq) ? Mn2+(aq...
Sunday, November 15, 2015 by Dalton

Analytical Chemistry
I have a 0.00156 M solution of CuSO4*5H2O in water (from 0.0398 g of CuSO4*5H20 in 100 mL of water). How would I calculate the ppm of Cu of that solution from that information?
Sunday, November 15, 2015 by Ronnie

Chemistry 102
The average human body contains 6.00 L of blood with a Fe2+ concentration of 2.00×10−5 M . If a person ingests 6.00 mL of 16.0 mM NaCN, what percentage of iron(II) in the blood would be sequestered by the cyanide ion?
Sunday, November 15, 2015 by Kyle

Chemistry
What materials would be produced in the electrolysis of the following reagents? Please make sure that you correctly balance the equations! Also, please note the states of the reagents. NaCl (aq) --> NaCl (l) --> KBr (l) -->
Sunday, November 15, 2015 by Evan

Chemistry
Given: PbSO4 + 2e− Pb + SO42− E° = -0.356 V PbO2 + 4H+ + SO42− + 2e− PbSO4 + 2H2O E° = 1.685 V Determine the cell voltage of the lead storage battery when the concentration of sulfuric acid is 4.00 M. Where do I start, thank you
Sunday, November 15, 2015 by Anonymous

chemistry
The average chemical bond energy in DNA molecules is about 300.00Kj per 6.02E23 bonds, estimate the number of chemical bonds that can be ruptured by a 1E-9m x-ray photon.
Sunday, November 15, 2015 by Brooke N

Chemistry
Calculate the standard enthalpy change for the reaction 2A+B⇌2C+2D Use the following data: Substance ΔH∘f (kJ/mol) A -251 B -403 C 213 D -511 My thoughts: [(2)(-511)+(213)(2)]-[(2)(-251)+(-403)]=​309kJ (but apparently that is not the correct answer) What...
Sunday, November 15, 2015 by Miranda

Chemistry
A 0.120 g sample of a diprotic acid of unknown molar mass is dissolved in water and titrated with 0.1218 M NaOH. The equivalence point is reached after adding 12.4 mL of base. What is the molar mass of the unknown acid?
Sunday, November 15, 2015 by Jorge

Chemistry
1. A hypothetical pure element consists entirely of two isotopes. The natural percent abundance of the isotope with mass 25.5 u is 86.1%. The other isotope has mass 29.2 u. Calculate the atomic weight of the naturally occurring element. 2. Suppose that a hypothetical element ...
Sunday, November 15, 2015 by Melissa

Chemistry
Which molecule contains a polar covalent bond? a)C2H4 b)ZnS c)LiI d)NBr3 e)AgI
Sunday, November 15, 2015 by Mark

Chemistry Dr. BOB
In many residential water systems, the aqueous Fe3+ concentration is high enough to stain sinks and turn drinking water light brown. The iron content is analyzed by first reducing the Fe3+ to Fe2+ and then titrating with MnO4- in acidic solution. Fe2+(aq) + MnO4-(aq) ? Mn2+(aq...
Sunday, November 15, 2015 by Dalton

chemistry
A standard sodium carbonate solution is prepared in a 250 cm^3 volumetric flask during a titration,20 cm^3 of a 0,1 mol.dm^-3 nitric acid solution neutralises 25 cm^3 of the above standard solution according to the following balanced equation 2HNO3(aq) Na2CO3(aq)=>2NaNO3(aq...
Sunday, November 15, 2015 by alex

Chemistry
10000 tonnes of iron reacted in a blast furnace Fe2O3 calculate the typical mass of iron produced each day
Sunday, November 15, 2015 by Anonymous

Chemistry
A student performed an experiment to determine the molecular weight of a gaseous compound. Using the ideal gas law PV = nRT, and knowing the pressure, temperature, and volume of the vapor, the student calculated the number of moles of gas, n, to be 0.0443 mol. The weight of ...
Sunday, November 15, 2015 by Ericka

Chemistry
A 0.120 g sample of a diprotic acid of unknown molar mass is dissolved in water and titrated with 0.1218 M NaOH. The equivalence point is reached after adding 12.4 mL of base. What is the molar mass of the unknown acid?
Sunday, November 15, 2015 by Jorge

chemistry
Consider an atom traveling at 1% of the speed of light. The de Broglie wavelength is found to be 9.50 × 10–3 pm. Which element is this?
Saturday, November 14, 2015 by Anonymous

Chemistry
You have a 250ml solution of 0.13M calcium iodate. How many grams of potassium iodate need to be added to the solution to begin to precipitate calcium iodate? The solubility product constant for calcium iodate is6.47 *10^-6. B) you have a 250ml solution of 0.13 M calcium ...
Saturday, November 14, 2015 by Jack

Chemistry
Given the following half-reactions and their standard reduction potentials, Ni2+ + 2e− Ni E° = -0.25 V 2H+ + 2e− H2 E° = 0.00 V Ag+ + e− Ag E° = 0.80 V a spontaneous reaction will occur between: a. Ni2+ and H2 b. H+ and Ag c. Ag+ and Ni d. Ni2+ ...
Saturday, November 14, 2015 by Anonymous

Chemistry
What is the frequency of the photons emitted by hydrogen atoms when they undergo transition from n=4 to n=3?
Saturday, November 14, 2015 by Terrill

chemistry
draw a diagram showing the arrangement of the valency electrons in a molecule of the covalent compound arsine,ash3 use o to represent an electron from aresenic
Saturday, November 14, 2015 by ahmad

Chemistry
What is the minimum volume of 2.6 M HBr required to completely dissolve 35.0 g of potassium metal?
Saturday, November 14, 2015 by Jorge

chemistry
In many residential water systems, the aqueous Fe3+ concentration is high enough to stain sinks and turn drinking water light brown. The iron content is analyzed by first reducing the Fe3+ to Fe2+ and then titrating with MnO4- in acidic solution. Fe2+(aq) + MnO4-(aq) ? Mn2+(...
Saturday, November 14, 2015 by Dalton

chemistry
Calculate the volume occupied by 7g of nitrogen gas at 27 degree c and 750 mm of hg pressure
Saturday, November 14, 2015 by g srinivasa rao

Chemistry
When sodium chloride, NaCl, is added to water, it forms a solution. Rank the steps involved in the dissolution of salt in water from first step to last step. To rank items as equivalent, overlap them. a.) NaCl crystal is added to water b.) NaCl solution c.) The Na ions are ...
Saturday, November 14, 2015 by LuigiR

Chemistry
You have a large amount of 8.00 M stock solution. You need 1.60 L of 3.00 M solution for an experiment. How would you prepare the desired solution without wasting any stock solution? A.) Start with 1.60 L of water. Add stock solution until you reach a total volume of 2.56 L . ...
Saturday, November 14, 2015 by LuigiR

chemistry
calculate the pH of 5M aqueous ammonia. Given kb=1.8 x 10^-5
Saturday, November 14, 2015 by Nor Syafinas

Chemistry
2.1 g of a hydrocarbon fuel is burned in a calorimeter that contains 280 grams of water initially at 25.00◦C. After the combustion, the temperature is 26.55◦C. How much heat is evolved per gram of fuel burned? The heat capacity of the calorimeter (hardware only) is...
Friday, November 13, 2015 by Amy

Chemistry
A piece of metal of mass 25 g at 94◦C is placed in a calorimeter containing 57.4 g of water at 24◦C. The final temperature of the mixture is 34.2 ◦C. What is the specific heat capacity of the metal?Assume that there is no energy lost to the surroundings. ...
Friday, November 13, 2015 by Amy

Chemistry
Pyrites, FeS2, are a pollution-causing impurity in some coals. Upon combustion, the following rxn takes place: 2FeS2 + 5O2 à 4SO2 + 2FeO What volume of 6.0 M NaOH would be required to react with the SO2 produced from 1000 kg of coal containing 0.050% by mass of pyrite ...
Friday, November 13, 2015 by Mary White

Chemistry (Check)
6.3 mg of a boron hydride is contained in a flask of 385 mL at 25. degrees C and a pressure of 11 Torr. A. determine the molar mass of the hydride. B. which of the following hydrides is contained in the flask, BH3, B2H6, or B4H10 A. MM = 27.597 g/mol B. B2H6
Friday, November 13, 2015 by Anonymous

Chemistry
Calculate the density (g/L) of 478 mL of krypton at 47 degrees C and 671 mmHg. I wasn't sure about this one but I got: density = 2820 g/L with sig figs
Friday, November 13, 2015 by Anonymous

Chemistry (Check)
A sample of helium has a volume of 521 cc at a pressure of 75 cmHg and a temperature of 18 degrees C. When the temperature is increased to 23 degrees C, what is the volume of the helium? Vf = .530 L
Friday, November 13, 2015 by Anonymous

Chemistry (Check)
Calculate the mass of 15.0 L of NH3 at 27 degrees C and 900 mmHg. Mass of NH3 = 12.2 g
Friday, November 13, 2015 by Anonymous

Chemistry (Check)
A container holds 500. mL of CO2 at 20. degrees C and 742 Torr. What will be the volume of the CO2 if the pressure is increased to 795 Torr? Vf = .465 L
Friday, November 13, 2015 by Anonymous

Chemistry
Given 300.0 mL of a gas at 17.0 degrees C. What is its volume at 10.0 degrees C? Vf = .293 L
Friday, November 13, 2015 by Anonymous

Chemistry (Check)
A 30.0 L sample of nitrogen inside a rigid, metal container at 20.0 degrees C is placed inside an oven whose temperature is 50.0 degrees D. The pressure inside the container at 20.0 degrees C was at 3.00 atm. What is the pressure of the nitrogen after its temperature is ...
Friday, November 13, 2015 by Anonymous

Chemistry (Check)
Chlorine gas, Cl2, is widely used to purify municipal water supplies and treat swimming pool waters. If it occupies 23.5 cm^3 at STP, what volume will it occupy at -270. degrees C and a pressure of 1520 Torr? Vf = 1.29 x 10^-4
Friday, November 13, 2015 by Anonymous

Chemistry (Check)
A sample of gas has a volume of 12.0 L and a pressure of 20kPa. If the pressure of gas is increased to 50 psi, what is the new volume of the gas? Vf = 6.96 L
Friday, November 13, 2015 by Anonymous

Chemistry (Check)
How many molecules are there in 985 mL of nitrogen at 0.0 degrees C and 1.00x10^-6 mmHg? 3.50 molecules
Friday, November 13, 2015 by Anonymous

Chemistry (Check)
If a gas in a closed container is pressurized from 12 atm to 25 atm and tis original temperature was 32 degrees C, what would the final temperature of the gas be? Tf = 635 K
Friday, November 13, 2015 by Anonymous

Chemistry
An atom has a mass number of 39. If it has 20 neutrons, calculate its atomic number.
Friday, November 13, 2015 by Onyi

Chemistry-Dr.Bob
Calculate the mass of Fe(OH)3 s) produced by mixing 50.0 mL of 0.153 M KOH (aq) and 25.0 mL of 0.255 M Fe(NO3)3 (aq), and the number of moles of the excess reactant remaining in solution.
Friday, November 13, 2015 by Rucha

Chemistry
If the 50.00mL sample from problem 3 above was titrated with EDTA,what volume of a 0.00420 M EDTA solution would be needed to reach the endpoint? (Your answer should be given in milliliters.) (Problem 3 found that .0000625 moles of calcium carbonate were present in the sample)
Friday, November 13, 2015 by Alex

chemistry
Determine the pH of a 1 M aniline solution (Kb = 4.2 10-10). I am unsure how to start, any help?
Friday, November 13, 2015 by Logan

Chemistry
You have a large amount of 8.00 M stock solution. You need 1.60 L of 3.00 M solution for an experiment. How would you prepare the desired solution without wasting any stock solution?
Friday, November 13, 2015 by LuigiR

Chemistry
You have a large amount of 8.00 M stock solution. You need 1.60 L of 3.00 M solution for an experiment. How would you prepare the desired solution without wasting any stock solution?
Friday, November 13, 2015 by LuigiR

Chemistry
Show that the reaction caco3 ->cao+co2 is not a redox reaction
Friday, November 13, 2015 by Pooja

Chemistry
Show that the reaction caco3 ->cao+co2 is not a redox reaction
Friday, November 13, 2015 by Anonymous

Chemistry
Isomers are compounds that have the same number and kinds of atoms but have a different arrangement of the atoms. The enthalpies of atom combination for several pairs of gaseos isomers are given here. For each pair, decide which has the strongest bonds. a. CH3CH2CH2OH -4391....
Friday, November 13, 2015 by Sarah

Chemistry
Carbon disulfide (CS2) is useful, but flammable, solvent. Calculate DH for the following reaction. CS2(l) + 3O2(g) --> CO2(g) + 2SO2(g)
Friday, November 13, 2015 by Anonymous

chemistry
can some one help me with a few chem questions please. A chunk of iron weighs 4.32 g. a) How many iron atoms are there in this sample? 55.85 g Fe = 1.00 mol Fe = 6.022 x 1023 atoms Fe b) How many moles of iron are there in this sample? 2. . You have a copper bar weighing 71.24...
Thursday, November 12, 2015 by anna

Chemistry
Use the following data 2C(s) + 4H2(g) --> C3H8(g) DH= -103.85 kJ/molrxn C(s) + O2(g) --> CO2(g) DH= -393.51 kJ/molrxn H2(g) + 1/2O2(g) --> H2O(g) DH= -241.82 kJ/molrxn to calculate the heat of combustion of propane, C3H8 C3H8(g) + 5O2(g) --3CO2(g) + 4H20(g)
Thursday, November 12, 2015 by Anonymous

Chemistry
Predict the Order of increasing bond length for (i) H2(g) (ii) I2(g) (iii) F2(g) I don't know how I should know
Thursday, November 12, 2015 by Anonymous

chemistry
1. In the reaction 2Ca(s) + O2(g) → 2CaO(s), which species is oxidized?
Thursday, November 12, 2015 by anna

chemistry
1. How many grams of calcium chloride (CaCl2) are there in 600.0 mL of an aqueous solution that has a concentration of 0.450 M CaCl2? 2. The conjugate base of HS- is: 3. What mass of calcium chloride, CaCl2, is needed to prepare 3.65 L of a 1.75 M solution? The molar mass of ...
Thursday, November 12, 2015 by angel

Chemistry
Predict whether each of the following reactions would be exothermic or endothermic. a. CO(g) --> C(g) + O(g) b. 2H(g) + O(g) --> H20(g) c. Na+(g) + Cl-(g) --> NaCl(s) What is the sign of DH in each of these reactions? Please explain. I am very confused. Thanks
Thursday, November 12, 2015 by Anonymous

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