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November 23, 2014

Search: Consider a sample containing 2.00 mol

Number of results: 21,521

AP Chemistry
Consider a 50.4 g sample of H2O(g) at 115C. What phase or phases are present when 156 kJ of energy is removed from this sample? Specific heat capacities: ice, 2.1 J/gC; liquid, 4.2 J/gC; steam, 2.0 J/gC, Hvap = 40.7 kJ/mol, Hfus = 6.02 kJ/mol. (Select all that apply...
November 28, 2008 by Robert

analytical chemistry
at elevated temperature, NaHCO3 (83.98g/mol) is converted quantitatively to Na2CO3 (105.98g/mol).Ignition of 0.3592g sample of an antacid tablet containing NaHCO3 and non volatile impurities yielded a residue weighing 0.2362g. Calculate the percent purity of the sample.
January 26, 2014 by Anonymous

Chemistry
consider 2 sample of nitrogen gas. sample 1 contains 1.5 mol of N2 and has a volume of 36.7L at 25C and 1 atm. sample 2 has a volume of 16.5L at 25C and 1 atm. calculate the number of moles of N2 in sample 2 do i use the pv= nrt equation? and do i only use the information ...
June 8, 2010 by Anonymous

Chemistry help
Hello. Can I get someone to help me set up these problems? 1.) How many moles of N are there in 2.6 moles of NHO3? 2.) How many moles of C2H6 (g) are consumed when 4.4 mol CO2 (g) are produced? 3) How many milliliters of 0.80 M CuSO4 must be diluted to make 866 milliliters of ...
February 25, 2007 by Nazr

Chemistry [back-titration] - please check my sol'n
A 7.00 gram sample containing the mineral tellurite was dissolved then treated with 70.0 mL of 0.03114 M K2CrO7. 3 TeO2 + Cr2O7 ^2- + 8 H+ -> 3 H2TeO4 + 2 Cr3+ + H2O When reaction is complete, the excess Cr2O7 2- required a 14.05 mL back titration with 0.1135 M Fe2+. ...
March 19, 2014 by Nina

Chemistry
Consider the reaction: CO(g) + H2O (g) <---> CO2(g)+H2(g) which of the following initial composition will NOT achieve equlibrium? a) 0.25 mol H2, 0.35 mol CO2, and 0.25 mol CO b) 0.25 mol CO, 0.75 mol H2O c) 1.0 mol of CO2 and 0.50 mol H2 d) 0.85 mol CO and 0.25 mol H2 ...
November 9, 2012 by Ania

chemistry
A 1.252g sample containing iron is dissolved and converted to FE 2+ followed by addition of 25ml of 0.01M k2 cr2 07. The excess K2cr207 required 6.85 ml of 0.015M. Find the percentage FE304 FW 231g/mol in the sample. The right 7.96% Who helps me
December 16, 2012 by Fai

chemistry
a sample containing 1.50 mol neon gas has a volume of 8.00L.what is the new volume of the gas in liters when the following changes occur in the quantity of the gas at constant pressure and temperature? a.a leak allows on-half of the neon atoms to escape. b. a sample of 25.0g ...
June 27, 2010 by Jetta

Chemistry
Hello. Can I get someone to help me set up these problems? 1.) How many moles of N are there in 2.6 moles of NHO3? 2.) How many moles of C2H6 (g) are consumed when 4.4 mol CO2 (g) are produced? 3) How many milliliters of 0.80 M CuSO4 must be diluted to make 866 milliliters of ...
February 25, 2007 by Nathan

chemistry
A 1.252g sample containing iron dissolved and converted to Fe followed by ADDITION OF 25ML OF 0..01m K2CR2 07. THE EXCESS K2CR207 REQUIRED 6.85ML OF 0.015m SN2+. Find the percentage fe3 04 fw 213g/mol in the sample. Who helps me
December 11, 2012 by Fai

Chemistry
1.) A 3.000gram sample of a hydrate compound containing Co, C2O4, and H2O was combusted to give 1.316g of Co3O4. What is the percentage of Cobalt in the oxide? 3.) 2.000 grams of a sample containing Co, C2O4, and H2O showed there to be 0.9621g of oxalate in the sample. Was is...
March 3, 2013 by Robert

General Chemistry I
A sample of a compound containing only Br and O reacts with an excess of H2 to give 6.601 g of HBr and 3.919 g of H2O. What is the empirical formula of this compound? a. BrO b. BrO2 c. Br2O d. BrO3 e. None of the above I already know the answer is (e), but I am not entirely ...
December 3, 2012 by Emily

chemistry
Consider a mixture of the two solids BaCl2 * 2H2O (FW=244.26 g/mol) and KCl (FW=74.551 g/mol). When the mixture is heated to 160 C for 1 hour, the water of crystallization is driven off: BaCl2 * 2 H2O (s)  BaCl2(s) + 2 H2O(g) A sample originally weighing 1.7839 g is ...
February 24, 2013 by Anonymous

Chem
A sample containing 1.2x10^-2 mol HCl is completely neutralized by 100.0mL of Sr(OH)2 what is the [Sr(OH)2]?
December 15, 2010 by Anonymous

(5) Chemistry - Science (Dr. Bob222)
Consider a buffer made from 0.13 M sodium acetate and 0.10 M acetic acid in 1L. What amount of KOH must be added to cause an increase of the pH by 0.14? A) 0.048 mol B) 0.038 mol C) 0.028 mol D) 0.018 mol E) 0.008 mol
May 6, 2014 by Ana

chemistry
a 0.0500 mol sample of a nutrient substance is burned in a bomb calorimeter containing 2.00 x 10^2g H2O. If the formula weight of this nutrient substance is 114g/mol, what is the fuel value (in nutrient Cal) if the temperature of the water increased 5.70C
April 15, 2014 by ana

Physics
A 35.41-g sample of Cu(s) at 96.73C was added to a constant-pressure calorimeter containing 148.3 g of H2O(l) at 25.20C. The final temperature of the system was 26.66C. Assuming no heat loss to the surroundings, what is the calorimeter constant? C(Cu) = 24.435 J/mol.K; C(...
September 25, 2012 by cry baby

Chemistry
A student mixed 75.0 mL of water containing 0.75 mol HCI at 25* C with 75.0 mL of water containing 0.75 mol of NaOH at 25*C in a foam cup calorimeter. The temperature of the resulting solution increased to 35*C. How much heat in kilojoules was released by this reaction? C (...
April 27, 2011 by Tarra

chemistry
calculate3 the concentrationof chloride in water sample Mw using this equation mol Ag+ = 1= MxVwx10-3 = MxVw mol Cl- 1 Mwx20.00x10-3 Mwx20 so M x Vw=Mw x20 or Mw= M x Vw 20 Mw= ? mol/L chloride in water sample= ? mmol/L Mw=? g/L chloride in water sample Mw=?ppm in water sample...
June 2, 2012 by lynda

chemistry
Consider the balanced equation 2A(g) + 3G(g) \ 2X(g) + Z(g). To a 20.0 L container maintained at a temperature of 127 C were added 0.200 mol of A, 0.500 mol of G, 0.400 mol of X, and 0.600 mol of Z. After equilibrium was established, it was found that 0.340 mol of X was ...
July 27, 2008 by alexis

Chemistry e
The rusting of iron is represented by the equation 4Fe +3O2 --> 2Fe2O3. If you have a 1.50-mol sample of iron, how many moles of Fe2O3 will there be after the iron has rusted completely? a. 0.50 mol b. 0.75 mol c. 1.0 mol d. 1.50 mol e. 2.0 mol --> I got "b" using ratios...
January 18, 2011 by Kaye

chemistry
Use the systematic treatment of equilibrium to determine the pH and concentrations of species in 1.00 L of solution containing 0.065 mol citric acid (H3A), 0.025 mol 8-hydroxyquinoline (HB), and 0.040 mol KOH. Consider just acid-base chemistry. Ignore ion pairing and activity ...
May 23, 2014 by James

Chemistry ?
How many moles are contained in a 4.67-L sample of gas at 30C and 199 kPa? A. 1.7 mol B. 11.8 mol C. 0.37 mol D. 3.7 mol I guessed D, but I'm not sure.
August 15, 2013 by Kaylee

Chem -plz check work
suppose that 2.00 mL of 0.01 mol/L sodium sulphide is used to test a 50.0 mL sample of water containing 0.0005 mol/L mercury nitrate ions. What mass of precipate is formed? Na2 = Hg(NO3)2 --->2NaNO3 + HgS My Work: nNa2S=0.002*0.01 =0.0002 mol nHg(NO3)2=0.05*0.0005 =0....
May 28, 2008 by Lori

Chemistry
A sample weighing 3.064 g is a mixture of Fe2O3 (molar mass = 159.69) and Al2O3 (molar mass = 101.96). When heat and a stream of H2 gas is applied to the sample, the Fe2O3 reacts to form metallic Fe and H2O(g). The Al2O3 does not react. If the sample residue weighs 2.407 g, ...
October 29, 2012 by Chris

CHEMISTRY
Consider a 58.4 g sample of H2O(g) at 125C. What phase or phases are present when -162 kJ of energy is removed from this sample? Specific heat capacities: ice, 2.1 J g-1 C-1; liquid, 4.2 J g-1 C-1; steam, 2.0 J g-1 C-1, ΔHvap = 40.7 kJ/mol, ΔHfus = 6.02 kJ/mol. (...
November 17, 2012 by Sarah

chemistry
a 2.52-g sample of a compound containing only carbon, hydrogen, nitrogen, oxygen, and sulfur was burned in excess O to yield 4.23 g of CO2 and 1.01 g of H2O as the only carbon and hydrogen containing products respectively. Another sample of the same compound, of mass 4.14 g, ...
February 15, 2014 by Grace

Chemistry
A compound contains only potassium and iodine. A sample weighing 12.3 g of this compound contained 2.90 g of potassium. How many grams of iodine would there be in another sample of this compound containing 9.56 g of potassium? Do I find the mol of each (12.3 g, 2.90 g) or am I...
October 6, 2014 by Madoo

chemistry
A student mixed 75.0 mL of water containing 0.75 mol HCl at 25�C with 75.0 mL of water containing 0.75 mol of NaOH at 25�C in a foam cup calorimeter. The temperature of the resulting solution increased to 35�C. How much heat in kilojoules was released by ...
February 7, 2012 by Alexis

Analytical chemistry
I did the next problem, i don't have the results for it and i just want to know if i calculated the mass for Fe2O3 the right? A sample is a mixture of iron oxides (Fe2O3 and FeOOH). It's known that at 200C this reaction occurs: 2FeOOH(s)-> Fe2O3(s) + H2O(g) A 0.2564g ...
September 7, 2013 by Gloria

chemistry
A 79.9-L sample of a gaseous hydrocarbon, measured at 1.00 atm pressure and 25.0C, 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 Hf (kJ/mol) CO2(g) 393.5 ...
March 30, 2011 by chemistry

chemistry please help
calculate the concentration of silver nitrate in mol/L M x V =0.2 average Vw in ml of 2.23 2.26 2.43 MxVw = Mwx20 Mw=? mol/L chloride in water sample = mmol/L? =?g/L chloride in sample =?ppm chloride in water sample
June 4, 2012 by lynda

Chemistry
1. A solution containing 0.100 mol of Na2CO3 and 0.100 mol of NiCl2 is allowed to react. Which reactant is the limiting reactant? 2. A solution containing 0.100 mol of Na2CO3 and 0.100 mol of NiCl2 is allowed to react. How many moles of precipitate form in this reaction?
February 23, 2013 by Eagertolearn

chemistry
2.00mL of 0.01 mol/L aqueous sodium sulphide is used to test a 50.omL sample of water containing 0.0005 mol/L mercury (II) nitrate ions. What mass of precipitate is formed? Na2S + Hg(NO3)2 --- 2NaNo3 + HgS determine limiting reactant using limiting reactant, calculate the ...
August 13, 2010 by Kelsey

Chemistry
"An aqueous sodium borate solution is titrated to the second endpoint with 0.225 mol/l nitric acid in the presence of a suitable indicator. If an average of 12.6mL of titrant are required to reach the second endpoint for a 25.0 mL sample, what is the base concentration?" My ...
May 15, 2010 by Stuck

Chemistry
What is the concentration of a solution of lithium carbonate containing 0.01 mol in 750 mL of solution What volume of 0.01 mol L-1 Li2CO3 solution would contain 0.035 mol lithium carbonate? Give your answer as 2 sig fig (this is technically not correct), followed by a space ...
June 13, 2012 by Preity Zinta

Chemistry
A 1.00 L flask containing the equilibrium mixture CO +Cl2 <-> COCl2 was found to contain 0.400 mol of COCl2, 0.100 mol of CO, and 0.500 mol of Cl2. If 0.300 mol of CO is added at constant temperature, what will be the new concentrations of each component at equilibrium?(...
April 29, 2012 by Divya

chemistry
Consider the following reaction at 298 K: C(graphite) +2Cl2 (g) -----> CCl4(l) Calculate the following quantities. Delta H: -139 kJ/mol deltaS(sys)=? J/mol*K deltaS(surr)=? J/mol*K deltaS(univ)=? J/mol*K My answer is: deltaS(sys)=654.9J/mol*K deltaS(surr)=0.4664 J/mol*K ...
March 14, 2012 by Kelsey

chemistry
Nitrosyl bromide decomposes according to the following equation. 2NOBr (g)(equilibrium arrow) 2NO (g) + Br2 (g) A sample of NOBr (0.64 mol) was placed in a 1.00-L flask containing no NO or Br2. At equilibrium the flask contained 0.46 mol of NOBr. How many moles of NO and Br2, ...
November 19, 2010 by jessie

Chemistry
A 0.5595 g sample of a compound containing C, H, and O was burned to produce 1.429 g CO2 and 0.5850 g H2O. If the molar mass of the compound was determined to be approximately 86.13 g/mol, what is its molecular formula?
January 19, 2012 by Mark

Chemistry
A 0.5595 g sample of a compound containing C, H, and O was burned to produce 1.429 g CO2 and 0.5850 g H2O. If the molar mass of the compound was determined to be approximately 86.13 g/mol, what is its molecular formula?
January 20, 2012 by mark

chem class
Nitrosyl bromide decomposes according to the following equation. 2NOBr (g)(equilibrium arrow) 2NO (g) + Br2 (g) A sample of NOBr (0.64 mol) was placed in a 1.00-L flask containing no NO or Br2. At equilibrium the flask contained 0.46 mol of NOBr. How many moles of NO and Br2, ...
November 18, 2010 by jessie

Chemistry problem
Hi I'm stuck on these questions can you please help me A soil sample contains 0.2234 g of Fe3+ per 100g. Fe3+ is precipitated when the soil becomes alkaline as shown in the equation below. Fe3+ + 3OH- + (x-1)H2O _ FeOOH.xH2O(s) This soil is sprayed with 40.0 wt% urea solution...
March 26, 2010 by Sarah

chemistry
The equilibrium constant (Kc) for the gas phase reaction 2 NH3 N2 + 3 H2 is 3.0 x 10-3 at some temperature. The reaction is started by placing a 0.040-mol sample of ammonia in an empty one-liter flask. When equilibrium is established how much N2 is present? 1. ) 0.019 mol 2...
October 25, 2009 by James

chemistry
A 0.6996 g sample of a compound containing C, H, and F was burned to produce 0.6039 g CO2 and 0.1235 g H2O. If the molar mass of the compound was determined to be approximately 102.0 g/mol, what is its molecular formula?
January 20, 2012 by kenny

Science- Chemistry
How do I figure these out? A solution of sodium thiosulfate, Na2S2O3, is 0.1365 M. 29.28 mL of this solution reacts with 39.79 mL of I2 solution. What is the molarity of the I2 solution? 2(Na2S2O3) + I2↔Na2S4O6 + 2(NaI) 16.77 mL of the I2 solution from above is required...
November 8, 2012 by Whitney

chemistry
An ice cube of mass 10g at -10C is added to the beaker containing 150mL of water at 88.5C. Assuming no heat is lost to the surrounding; calculate the equilibrium temperature for the liquid after the ice melts.(Heat of fusion for H2O = 6.01 kJ/mol. Heat of vaporization 40.67kJ/...
June 21, 2012 by Bill

Chemistry
An ice cube of mass 10g at -10C is added to the beaker containing 150mL of water at 88.5C. Assuming no heat is lost to the surrounding; calculate the equilibrium temperature for the liquid after the ice melts.(Heat of fusion for H2O = 6.01 kJ/mol. Heat of vaporization 40.67kJ/...
June 21, 2012 by Anonymous

Chem Quanti
An organic pesticide (MW 183.7) is 8.43% Cl. A 0.627-g sample containing the pesticide plus inert material containing no chloride was decomposed with metallic sodium in alcohol. The liberated chloride ion was precipitated as AgCl weighing 0.0831 g. Calculate the percentage of ...
January 16, 2012 by Charmaine

ap chemistry
A 0.456 gram sample of an unknown mono- protic acid (lets call it HZ) was dissolved in some water (you pick the amount). Then the acidic solution was titrated to the equivalence point with 32.5 mL of 0.174 M KOH. What is the molecular weight of the unknown acid HZ? 1. 103.2 g...
March 5, 2013 by cheri

Chemistry
What is [OH-] of a solution containing 013 mol Ba(OH)2 and .021 mol KOH in .50L of H2O?
November 13, 2010 by donna

math who me step by step
25g of a sample of ferrous sulphate was dissolved in water containing dilute h2s04 and the volume made up to one litre. 25ml of this solution required 20ml of N/10 kmn04 solution for complete oxidation. Calculate the percentage of fes047h20 in the sample the right answer 88.96...
January 1, 2014 by Fai

chemistry
A 625mL sample of an aqueous solution containing 0.275 mol propionic acid (CH3CH2CO2H),has [H30+]= 0.00239M. What is the value of Ka for propionic acid?
April 11, 2011 by papermate

chemistry
Duralin is an alloy of aluminium containing 4.5% manganese, 3.5% copper, and 0.45% magnesium. How much magnesium is present in a 90 g sample of this alloy? Answer in units of mol
November 6, 2011 by lynn

Chemistry
Duralin is an alloy of aluminium containing 4.5% manganese, 3.5% copper, and 0.45% magnesium. How much magnesium is present in a 32 g sample of this alloy? Answer in units of mol
October 9, 2013 by Susan

Chemistry
When a sample of I(g) (18.15 mol) is placed in 59.00 L reaction vessel at 605.0 C and allowed to come to equilibrium the mixture contains 6.938 mol of I2(g). What is the concentration (mol/L) of I(g)? 2I(g) = I2(g)
October 4, 2013 by plzprovidetheanswer

chemistry
A is a solution of HCL containing 7.30g/dm3.B is a solution ofX2CO3 containing 10.6g/dm3.assume that average volume of acid is 2.81cm3 and the volume of base is 25.00cm3.from your result and information .calculate (I)concentration of A in mol/dm3(ii)concentration of B in mol/...
May 26, 2014 by john kelechi

Chemistry
Consider the process where 1.3 moles of ice, initially at -30.0 C, is heated to 140.0 C at constant pressure of 1.00 atm. The molar heat capacities (Cp) for solid, liquid, and gaseous water (37.5 J K-1 mol-1, 75.3 J K-1 mol-1, 36.4 J K-1 mol-1, respectively) are assumed to be ...
January 30, 2014 by Bryan Josten

Chemistry
Consider the process where 1.3 moles of ice, initially at -30.0 C, is heated to 140.0 C at constant pressure of 1.00 atm. The molar heat capacities (Cp) for solid, liquid, and gaseous water (37.5 J K-1 mol-1, 75.3 J K-1 mol-1, 36.4 J K-1 mol-1, respectively) are assumed to be ...
January 31, 2014 by Bryan Josten

Chemistry
A sample of nitrogen containing 1.5x10^23 molecules has the same number of molecules as a sample containing A. 1.0 mole of H2 B. 2.0 moles of He C. 0.25 mole of O2 D. 0.50 mole of Ne
March 12, 2013 by Brandi

Chemistry
A sample of nitrogen containing 1.5x10^23 molecules has the same number of molecules as a sample containing A. 1.0 mole of H2 B. 2.0 moles of He C. 0.25 mole of O2 D. 0.50 mole of Ne
March 12, 2013 by Brandi

Damon check step by step
25g of a sample of ferrous sulphate was dissolved in water containing dilute h2s04 and the volume made up to one litre. 25ml of this solution required 20ml of N/10 kmn04 solution for complete oxidation. Calculate the percentage of f2s047h20 in the sample The right answer 88.96...
January 2, 2014 by Fai

chemistry
Is this correct? A 0.1471 g sample of a compound containing C, H, and F was burned to produce 0.1960 g CO2 and 0.08024 g H2O. If the molar mass of the compound was determined to be approximately 66.05 g/mol, what is its molecular formula? My answer is: C_12 H O_20
January 21, 2012 by mark

Chemistry 11
Find the percent composition of a compound containing sodium and chlorine if 24.34g of the compound contains 13.45g of sodium. My work: Molar mass of NaCl: MNa +MCl = 22.99 g/mol + 35.45 g/mol = 58.44 g/mol Percent composition of Na: 22.99 g/mol / 58.44 g/mol x 100 = 39.34% Na...
November 12, 2014 by Christina

chemistry
n one experiment, a mixture of 1.000 mol acetic acid and 0.5000 mol ethanol is brought to equilibrium. A sample containing exactly one-hundredth of the equilibrium mixture requires 28.80mL 0.1040M Ba(OH)2 for its titration. Calculate the equilibrium constant, , for the ethanol...
March 13, 2011 by gss

Chemistry
When a sample of I2(g) (0.07249 mol/L) is placed in 130.0 L reaction vessel at 865.0 K and allowed to come to equilibrium the mixture contains 0.1110 mol/L of I(g). What concentration (mol/L) of I2(g) reacted? I2(g) = 2I(g)
October 4, 2013 by plzprovidetheanswer

chemistry
Consider the hypothetical elements X and Y. Suppose the enthalpy of formation for the compound XY is {336 kJ/mol, the bond energy for X2 is 414 kJ/mol, and the bond energy for Y2 is 159 kJ/mol. Estimate the XY bond energy in units of kJ/mol.
December 13, 2010 by chemistry

chemistry
Consider the hypothetical elements X and Y. Suppose the enthalpy of formation for the compound XY is -336 kJ/mol, the bond energy for X2 is 414 kJ/mol, and the bond energy for Y2 is 159 kJ/mol. Estimate the XY bond energy in units of kJ/mol.
December 13, 2010 by Jude

chemistry
an aqueous solution contains 1 mol of S2O3 ions and this reduces 4 mol chlorine molecules.What is the sulphur containing product of this reaction?
February 10, 2013 by harish

chemistry
an aqueous solution contains 1 mol of S2O3 ions and this reduces 4 mol chlorine molecules.What is the sulphur containing product of this reaction?
February 10, 2013 by harish

chemistry
an aqueous solution contains 1 mol of S2O3 ions and this reduces 4 mol chlorine molecules.What is the sulphur containing product of this reaction?
February 10, 2013 by harish

statistics
Suppose that the percentage returns for a given year for all stocks listed on the new york stock exchange are approximately normally distributed with a mean of 12.4 percent and a standard deviation of 20.6 percent. Consider drawing a random sample of n=5 stocks from the ...
November 9, 2009 by ileana

chemistry who helps me step by step
25g of a sample of ferrous sulphate was dissolved in water containing dilute h2s04 and the volume made up to one litre. 25ml of this solution required 20ml of N/10 kmn04 solution for complete oxidation. calculate the percentage of fe204 7h20 in the sample. My calculation 0.02x...
January 11, 2014 by Fai

chemistry
Consider a sample containing 2.00 mol of a monatomic ideal gas that undergoes the following changes from State A to State D: State A PA=10.5atm, VA=10.00L State B PB=10.5atm, VB=5.00L State C PC=24.5atm, VC=5.00L State D PD=24.5atm, VD=22.00L Assume that the external pressure ...
October 4, 2008 by Jane

math steve for your help
25g of a sample of ferrous sulphate was dissolved in water containing dilute h2s04 and the volume made up to one litre. 25ml of this solution required 20ml of N/10 kmn04 solution for complete oxidation. Calculate the percentage of fes047h20 in the sample The answer 88.96% My ...
December 29, 2013 by Fai

Chemistry
A 0.450-gram sample of impure CaCO3(s) is dissolved in 50.0 mL of 0.150 M HCl(aq). The equation for the reaction is: CaCO3(s)+2HCl(aq) -> CaCl2(aq) + H2O(l) + CO2(g) The excess HCl(aq) is titrated by 9.75 mL of 0.125 M NaOH(aq). Calculate the mass percentage of CaCO3(s) in ...
April 10, 2012 by Katherine

chemistry
Here is the question: sodium hydride reacts with excess water to produce aqueous sodium hydroxide and hydrogen gas: NaH(s)+H2O-->NaOH(aq)+H2(g) A sample of NaH weighing ________g will produce 982mL of gas at 28.0 C adn 765 torr, when the hydrogen is collected over water. ...
June 17, 2009 by Gweedo

AP Chem
The energy change H associated with the reaction NBr3(g) + 3H2O(g) -> 3HOBr(g) + NH3(g) is +81 kJ/mol rxn. These bond energy values might be useful: O-H 459 kJ/mol; N-H 386 kJ/mol; O-Br 201 kJ/mol. The strength of the N Br bond is 1. 4 kJ/mol 2. 465 kJ/mol 3. 66 kJ/mol 4. ...
November 7, 2010 by Beth

Chemistry
The formaldehyde content of a pesticide preparation was determined by weighing 0.3124g of the liquid sample into a flask containing 50.0mL of 0.0996M NaOH and 50mL of 3% H2O2. Upon heating, the following reaction took place: OH- + HCHO + H2O2 -> HCOO- + 2H2O After cooling, ...
March 28, 2012 by Ellen

Chemistry
For a gas sample whose total pressure is 740 torr, what are the partial pressures if the moles of gas present are 1.3 mol N2, 0.33 mol O2, and 0.061 mol Ar?
November 15, 2014 by Aaqib Zaman

Chemistry
A rock sample contains only Sb2S3 and FeS. If 835g of the sample contains 11.2% antimony, what is the mass percent of the Sb2S3 in the sample? What is the mass percent of the sulfur in the sample? So far, I have determined that 11.2% of an 835g sample is 93.52g Sb, the molar ...
August 31, 2012 by Kristin

Chemistry
what is the resultig pH if 0.005 mol of NaOH is added to 100.0mL of buffer containing 0.010 mol acetic acid (CH3COOH,pKa = 4.74)and 0.010 mol sodium acetate (NaCH3COO)? (Assume the final volume is 100 mL) So i worked it out, i just need to double check the pH. Let me know what...
October 22, 2013 by Kyle

AP Chemistry
At 298K and 1 atm, a 0.5 mol sample of O2 and a seperate 0.75 mol sample of CO2 gas have the same: A. mass B. density C. average molecular speed D. average molecular kinetic energy E. number of atoms Please explain, and thanks for helping!
November 6, 2013 by Elizabeth

Chemistry Problem
Consider an ionic compound, MX, composed of generic metal M and generic halogen X. The enthalpy of formation of MX is Hf = 457 kJ/mol. The enthalpy of sublimation of M is Hsub = 121 kJ/mol. The ionization energy of M is IE = 433 kJ/mol. The electron affinity of X is EA = ...
February 2, 2013 by Anonymous

chemistry
Consider the following reaction at 298 K: C(graphite) +2Cl2 (g) -----> CCl4(l) Calculate the following quantities. Delta H: -139 kJ/mol deltaS(sys)=? J/mol*K deltaS(surr)=? J/mol*K deltaS(univ)=? J/mol*K My answer is: deltaS(sys)=-253.3J/mol*K deltaS(surr)=466.4 J/mol*K ...
March 16, 2012 by Leila

chemistry
Which of the following mixtures will be a buffer when dissolved in a liter of water? a. 0.1 mol Ca(OH)2 and 0.3 mol HI b. 0.3 mol NaCl and 0.3 mol HCl c. 0.4 mol NH3 and 0.4 mol HCl d. 0.2 mol HBr and 0.1 mol NaOH e. 0.2 mol H3PO4 and 0.1 mol NaOH i think e is answer but not ...
May 21, 2010 by George2

Chemistryy.
Some mole problems! Which quantity of neon may be represented by the symbol Ne? A) 1 gram B) 4 liters C) 6 x 1023 atoms D) 2 moles A sample of nitrogen containing 1.5 x 1023 molecules has the same number of molecules as a sample containing A) 1.0 mole of H2 B) 0.25 mole of O2 ...
June 6, 2011 by Jenny

Chemistry
A gas sample containing only SO3, CH2O and C2H6O2 has the following mass percent composition: 65.1% SO3 and 8.79% CH2O. Calculate the partial pressure (torr) of SO3 if the total pressure of the sample is 4712 torr. Unit conversion K = C + 273 1 atm = 760 torr Molar Mass (g/mol...
March 4, 2010 by Luc

chemistry
A 250.0 mL sample of an aqueous solution at 25 degrees Celsius contains 35.8 mg of an unknown nonelectrolyte compound. If the solution has an osmotic pressure of 11.25 mmHg, what is the molar mass of the unknown compound? a.) 237 g/mol b.) 484 g/mol c.) 351 g/mol d.) 699 g/mol...
October 2, 2012 by Bru

college chemistry
When a sample of HI(g) (5.825 mol) is placed in 320.0 L reaction vessel at 702.0 K and allowed to come to equilibrium the mixture contains 1.052 mol of H2(g). What is the equilibrium concentration (mol/L) of HI(g)? 2HI(g) = H2(g)+I2(g)
October 12, 2010 by sparkle

Quantitative Chemical Analysis
Hg has an AW of 200.59 g/mol and HgS has a MW of 232.66 g/mol. Compute the gram of Hg needed to prepare 20 g of standard containing 1% Hg(wt/wt) Then compute the gram of HgS needed to prepare 20 g of standard containing this same 1% (wt/wt).
September 4, 2012 by Kyuu

CHEMISTRY- answer check
A 0.386g sample of a protein was dissolved in water and made up to a volume of 60mL at 21.0C. At this temperature the osmotic pressure of this solution was 1.24mmHg. Calculate the molecular mass of the protein 12682 g mol-1 95025 g mol-1 9627613 g mol-1 5706 g mol-1 125.17 g ...
October 9, 2010 by lulu

AP chemistry
001 (part 1 of 2) 10.0 points A 1.37-gram sample of compound X (of MW 88.0 g/mol) was burned in a bomb calorime- ter containing 1700 g of water. A temperature rise of 0.95◦C was observed. ∆Erxn for this re- action is −475 kJ/mol of X. What is the heat ...
October 27, 2013 by Alyssa

Chemistry
if an aqueous solution of BA(NO3)2 is added to 1.0 L of a solution containing 0.05 mol F- and 0.075 mol SO4 2-, which salt will precipitate first?
April 26, 2010 by Matt

chemistry
What is the mole ratio of the reactants in a tube containing: Pb(NO3) 22.0mL 0.5 mol NaI 16.0mL 0.5 mol
March 10, 2010 by BT

chem
Consider the fermentation reaction of glucose: C6H12O6 ----) 2C2H5OH+2CO2 A 1.00-mol sample of C6H12O6 was placed in a vat with excess yeast. If 35.1 g of C2H5OH was obtained, what was the percent yield of C2H5OH?
March 14, 2013 by shane

Chemistry
A solution containing 0.100 mol of Na2CO3 and 0.100 mol of NiCl2 is allowed to react. What mass of precipitate forms in this reaction?
February 23, 2013 by Eagertolearn

AP Chemistry
The equilibrium constant for thermal dissociation of F2 F2(g)<->2F(g) is 0.300. If initially 1.00 mol F2 is placed in a 1.00 L container, which of the following is the correct number of moles of F2 that have dissociated at equilibrium? 1. 0.130 mol 2. 0.418 mol 3. 0.548 ...
November 26, 2013 by Gabriella

Chemistry
What is the ionic strength, I, of a solution at 25C containing 0.002 mol/L of BaSO4 and 0.001 mol/L of BaCl2? What is the activity coefficient of Ba2+ in this solution?
April 8, 2014 by Me

chemistry Damon check my calculation
25g of a sample of ferrous sulphate was dissolved in water containing dilute h2s04 and the volume made up to one litre. 25ml of this solution required 20ml of this solution required 20ml of n/10 kmn04 solution for complete oxidation. Calculate the percentage of f2s047h20 in ...
January 4, 2014 by Fai

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