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July 24, 2016

Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

chemistry lab
so i'm trying to finish my lab and im trying to solve for the concentration, and the lab handout says "remember all the cl- from the original sample ended up in 100 mL of solution" The concentration i solved for (from my graph) was 9.8 ppm Cl....how would i use a...
Saturday, April 23, 2016 by Anonymous

chemistry
Hi, I am trying to find the pH of a buffer I created and then added NaOH to. This is my data: total volume of solution 34.2 mL [NaOH] before reaction 6.0 [HOAc] before reaction .8 M [OAc-] before reaction .4 M [HOAc] after reaction 0 M [OAc-] after reaction 5.2 M So, how would...
Saturday, April 23, 2016 by anon

Chemistry
A flask initially contains 2.00 atm of NH3, 2.00 atm of N2, and 3.00 atm of H2 at 673 Kelvin. -What is the delta G for the reaction? -What is the equilibrium partial pressures of each gas at 673 Kelvin? So I figured out how to do the first question with relevant values: : ...
Saturday, April 23, 2016 by Chris

Chemistry
A reaction between gaseous sulfur dioxide and oxygen gas to produce gaseous sulfur trioxide takes place at 600◦C. At that temperature, the concentration of SO2 is found to be 1.14 mol/L, the concentration of O2 is 1.39 mol/L, and the concentration of SO3 is 3.18 mol/L. ...
Saturday, April 23, 2016 by Olivia

Chemistry
At equilibrium at 1.0 L vessel contains 22.00 mol of H2, 20.00 mol of CO2, 13.00 mol of H2O, and 5.700 mol of CO at 427◦C. CO2(g) + H2(g) ⇀↽ CO(g) + H2O(g) What is the value of K at this temperature for the reaction?
Saturday, April 23, 2016 by John

Chemistry
At 350 K, Kc = 0.142 for the reaction 2 BrCl(g) ⇀↽ Br2(g) + Cl2(g) An equilibrium mixture at this temperature contains equal concentrations of bromine and chlorine, 0.077 mol/L. What is the equilibrium concentration of BrCl?
Saturday, April 23, 2016 by Matthew

Chemistry
For the reaction H2(g) + I2(g) ⇀↽ 2 HI(g) at 425◦C, calculate [HI], given [H2] = [I2] = 0.000617 mol/L and K = 54.3.
Saturday, April 23, 2016 by Claire

BIO chemistry
What is the pH of a mixture of 0.042M NaH2PO4 and 0.054M Na2HPO4
Saturday, April 23, 2016 by umar Ahmad !@#$%^&u

Chemistry
In the lab we synthesised nickel (II) ammine tetraflouroborate using hydrated nickel chloride and ammonia then this solution was added to a slotion of ammonia and ammonium tetraflouroborate,now im struggling to write a fully balanced chemical reaction.Would anyone please help ...
Saturday, April 23, 2016 by Sikhulile

Chemistry
In the lab we synthesised nickel (II) ammine tetraflouroborate using hydrated nickel chloride and ammonia then this solution was added to a slotion of ammonia and ammonium tetraflouroborate,now im struggling to write a fully balanced chemical reaction.Would anyone please help ...
Saturday, April 23, 2016 by Sikhulile

Chemistry
Which of the following is a stronger lewis base: cyanide ion or dicarbide ion? I'm assuming it is the dicarbide ion as it is more negatively charged and a compound consisting of 2 carbons is larger and therefore more likely to lose electrons than something consisting of ...
Friday, April 22, 2016 by Kevin

AP Chemistry
The normal boiling point of methanol is 64.7°C. A solution containing a nonvolatile solute dissolved in methanol has a vapor pressure of 642.3 torr at 64.7°C. What is the mole fraction of methanol in this solution?
Friday, April 22, 2016 by Anonymous

Chemistry
On Standardization of 10 mL of NaOH approximately 0, 1 m with HCl, 9.5 mL of spent acid. Knowing that this acid was standardized with 5 mL of Na2CO3 0,05 m 0 where spent 4.8 mL determine the Molarity of HCl used and Molarity found to NaOH.
Friday, April 22, 2016 by Vitoria

chemistry
I hve a eq. Plzz tell me the product. Acetylene rects with H2S presence of Al2O3 with 400℃.
Friday, April 22, 2016 by tripti

Chemistry
Calculate the heat released when 42.0 g of water at 35.0 degrees Celsius is converted to ice at -5.0 degrees Celsius. The specific heat of ice is 2.03 J/(g C), the molar heat of fusion of ice is 6010 J/mol, and the specific heat of water is 4.18 J/(g C) (Hint: Be sure to ...
Friday, April 22, 2016 by Kiana

Chemistry
What is the solubility, in moles/liter, of PbCl2 if the Ksp =7.3 x 10^12
Friday, April 22, 2016 by Cadele

Chemistry
How do I answer this question? The average rate of disappearance of ozone in the reaction 2O3 --> 3O2 is found to be 8.12 x 10^-3 molecules over 15 seconds. What is the rate of appearance of O2 during this interval?
Friday, April 22, 2016 by Rose

chemistry
Consider the following reaction. 2 CO (g) + O2 (g) −→ 2 CO2 (g) What is most likely true about the entropy change for this reaction? Why would the delta s of the rxn be less than zero? thanks.
Friday, April 22, 2016 by anon

Chemistry
Which of the following has the highest boiling point? (Think of intermolecular forces) CHCl3, CH4, CH2Cl2, CH2I2, CHBr3, CHI3 Ive tried to answer this question twice and have one attempt left. Here's what I've done: CHCl3 -Boiling Point: -61.2 Degrees C -Molar Mass: ...
Friday, April 22, 2016 by Kiana

Chemistry
Consider the following reaction. 2 CO (g) + O2 (g) −→ 2 CO2 (g) What is most likely true about the entropy change for this reaction? Delta Srxn < 0 or Delta Srxn > 0. Why is it Delta Srxn < 0 ?
Friday, April 22, 2016 by Sam

Chemistry
How do you do the question: react 3.50 g of solid sodium metal with water to produce hydrogen gas and sodium hydroxide. If,at the end of the reaction there is 6.8 L of solution, what is the concentration of sodium hydroxide? This is realy quite urgent. I need to know for my ...
Friday, April 22, 2016 by Mr. Clueless

Chemistry
The pH of human blood needs to be between 7.35 and 7.45. You want to prepare a buffer solution that gives a pH of 7.40. You decide to use a sodium phosphate buffer: the acid is H2PO− 4 and the conjugate base is HPO2− 4 . You want the concentration of the acid to be...
Friday, April 22, 2016 by Emily

Chemistry
use the appropriate standard reduction potentials in the appendix of your book to determine the equilibrium constant at 285 K for the following reaction under acidic conditions 4H+(aq) + MnO2(s)+2Fe+2(aq)----> Mn+2 (aq)+2Fe3+(aq)+2H2O(l)
Friday, April 22, 2016 by Olivia

Chemistry
use the appropriate standard reduction potentials in the appendix of your book to determine the equilibrium constant at 285 K for the following reaction under acidic conditions 4H+(aq) + MnO2(s)+2Fe+2(aq)----> Mn+2 (aq)+2Fe3+(aq)+2H2O(l)
Friday, April 22, 2016 by Olivia

chemistry
Disilane gas undergoes combustion to form solid silicon dioxide and water
Friday, April 22, 2016 by Anonymous

chemistry
In an experiment, 95.0 mL of 0.225 M silver nitrate was mixed rapidly with 47.5 mL of 0.225 M calcium chloride in a coffee cup calorimeter. If a reaction occurred, was it exothermic or endothermic? If the reaction started at 23.7 °C, what is the final temperature of the ...
Friday, April 22, 2016 by -

chemistry
A 0.039 M solution of a weak acid (HA) has a pH of 4.28. What is the Ka of the acid?
Friday, April 22, 2016 by Syahira

Chemistry
4.13 grams of magnesium chloride were recovered after the chemical reaction between magnesium and chlorine gas occurred. If 7.10 grams of magnesium chloride was suppose to be produced, what is the percent yield of magnesium chloride?
Friday, April 22, 2016 by Christian

chemistry
to what temperature must a given mass of nitrogen at zero degree be heated so that both it volume and pressure will be doubled
Friday, April 22, 2016 by YUZARSIF

Chemistry
Which of the following is an endothermic reaction - rusting a nail in water - a cold pack, cooling - mixing strong hydrochloric acid and strong ammonium hydroxide - a heat pack
Thursday, April 21, 2016 by Alois

Chemistry
calculate the molarity of a NaOH solution that requires 42.55 mL to neutralize 3.53 grams of KHP
Thursday, April 21, 2016 by Klem

Chemistry
A type of hea that involves heated fluids, such as liquids or gases, moving and flowing is called?? Convection???
Thursday, April 21, 2016 by Boberto

Chemistry
A type of heat that involves no contact at all would be ?? Radiation
Thursday, April 21, 2016 by Boberto

Chemistry
A 500 mL buffer solution is 0.1 M benzoic acid and 0.10 M in sodium benzoate and has an initial pH of 4.19. What is the pH of the buffer upon addition of 0.010 mol of NaOH?
Thursday, April 21, 2016 by Nevaeh

Chemistry
A drop of liquid is about 0.05 mL. When doing a titration lab, 73 drops of base were used to reach end point; how many liters of base were required to neutralize the acid?
Thursday, April 21, 2016 by Bernice

Chemistry<--------
Sulfur dioxide in the effluent gases from coal-burning electric power plants is one of the principal causes of acid rain. One method for reducing SO2 emissions involves partial reduction ofSO2 to H2S followed by catalytic conversion of the H2S and the remaining SO2 to ...
Thursday, April 21, 2016 by Tyler

Chemistry -Dr.Bob222
Arrange the solutions in order of increasing acidity. NaCl, NH4Cl, NaHCO3, NH4CLO2, NaOH
Thursday, April 21, 2016 by Nevaeh

Chemistry
how many liters of CO2 and water vapor are produced by burning .3 liters of C2H2 (Acetylene) with .75 liters of O2? The balanced equation is: 2C2H2 + 5O2 = 2 H2O + 4CO2
Thursday, April 21, 2016 by Molly

Chemistry
2.16 grams of silver react with 3.20 grans of sulfur.Caculate the mass of silver sulfide produced (mass of ag=108.8g/mole)
Thursday, April 21, 2016 by GLORIA

Chemistry
Determine the pH of a solution made by diluting 25mL of 6.0 M HCl until the final volume of the solution is 1.75 L
Thursday, April 21, 2016 by Dylan

Chemistry - Answer Check
Find the molarity given 1.5 Liters of solution containing 62.5 g MgO. - 1.03 M Mgo There are 0.32 Liters of a 2.5 M HF solution. How many moles and grams of hydrofluoric acid are there? - 0.8 mol and 16 grams
Thursday, April 21, 2016 by Anonymous

Chemistry
A rigid container of O2 has a pressure of 3.9 atm at a temperature of 700 K. What is the pressure at 273 K?
Thursday, April 21, 2016 by Ashly

chemistry
aluminum metal combines with 22.40 liters of oxyen gas to form solid aluminum oxide
Thursday, April 21, 2016 by queen

Chemistry
How does changing the volume of strontium nitrate solution, added to 8 cm3 of sodium carbonate solution, affect the amount of precipitate formed? Is it the more the strontium nitrate solution is increased, the more precipate formed?
Thursday, April 21, 2016 by Ariana

chemistry
who prepaire tris buffer 0.2 mmol/lit calculation
Thursday, April 21, 2016 by rakesh

chemistry
Write the equilibrium constant expression for the reaction 2 NO (g) + Br2 (g) ↔ 2 NOBr (g)
Thursday, April 21, 2016 by Emilie

chemistry
Calculate the minimum volume oxygen gas that is required for the complete combustion of a mixture of 20cm carbon monoxide and hydrogen gas
Thursday, April 21, 2016 by lawal

Chemistry
Titration of 12.50 mL of HCl solution requires 22.50 mL of 0.1250 M NaOH solution. What is the molarity of the HCl solution?
Wednesday, April 20, 2016 by GraceW1

chemistry
How many joules of heat are removed to completely covert 80.0 grams of water to ice at zero Celcius? For water: c = 4.179 J/g °C Hfusion = 333.528J/g Hvap = 2258.601 J/g
Wednesday, April 20, 2016 by susan

chemistry
How many joules of heat are required to completely covert 85.0 grams of water at 40.0° C to steam at 100°C? For water: c = 4.179 J/g °C Hfusion = 6.01 kJ/mol Hvap = 40.7 kJ/mol
Wednesday, April 20, 2016 by har

Chemistry
Like a equilibrium constants, the values of Kw depends on temperature. At body temperature (37 C), Kw= 2.4 x 10^-14. What are the [H3O+] and pH of pure water at body temperature?
Wednesday, April 20, 2016 by Nevaeh

Chemistry
The equation for fermentation of glucose to alcohol and carbon dioxide is C6H12O6= 2C2H5OH + 2CO2 The enthalpy for the reaction is -67kj. Is the reaction endothermic or exothermic? Is the heat energy absorbed or released as the reaction occurs? I think its endothermic but im ...
Wednesday, April 20, 2016 by Megan

Advanced Chemistry
he vapor pressures of several solutions of water-propanol(Ch3Ch2Ch2OH) were determined at various compositions, with thefollowing data collected at 45C: XH2O Vapor pressure (torr) 0 74.0 .15 77.3 .37 80.2 .54 81.6 .69 80.6 .83 78.2 1.00 71.9 a.) Are solutions of water and ...
Wednesday, April 20, 2016 by Anonymous

chemistry
What is the main factor driving the difference in the spontaneity of the three reactions Cl^2,Br^2, and l^2?
Wednesday, April 20, 2016 by Linda

Chemistry
Calculate the total amount of heat that must be added to convert 15.7g of ice at its melting point to steam at 100.0°C
Wednesday, April 20, 2016 by Brian

Chemistry- Dr.Bob222
Determine [H30+], [OH-], and pH. A solution that is 0.655% HNO3 by mass (assume a density of 1.01 g/ mL for the solution).
Wednesday, April 20, 2016 by Nevaeh

Chemistry-Dr.Bob222
Like a equilibrium constants, the values of Kw depends on temperature. At body temperature (37 C), Kw= 2.4 x 10^-14. What are the [H3O+] and pH of pure water at body temperature?
Wednesday, April 20, 2016 by Nevaeh

math log rules / chemistry
hey so i have this equation i need to manipulate to solve for F- concentration. E1 = constant - 0.05916log[F] E2 = constant -0.05916log([F]+[Spiked]) E2-E1=-0.05916log(F+S) + 0.05916log[F] E2-E1/0.05916) = log[F+S] + log[F] how do I solve for log[F] ???
Wednesday, April 20, 2016 by help me :(

Chemistry
We did an experiment where we had to figure out the amount of water molecules in CuSO4xH2O (x being the value to find). If the stirring rod used was wet and was used to stir the beaker would this result in a higher x value? Is this a experimental or human error. Obviously this...
Wednesday, April 20, 2016 by John

Chemistry
Assuming the solution you used was 95% ethanol by volume and that the density of ethanol is 0.816g/mL, how much water and carbon dioxide are produced in the experiment? Equation: C2H6O+3O2-->2CO2+3H2O (You start off with 2.0 mL of ethanol)
Wednesday, April 20, 2016 by BUTCHER

Chemistry
Given the amount of limiting regeant that you started with, how many moles of solid product did you expect to produce? Started with 1.12g of iron LR - iron Equation is 2Fe + CuSo4 -> Fe2So4 + Cu
Wednesday, April 20, 2016 by Worm

Chemistry
A gas is trapped in a balloon. The gas chambee is 1.0 atm, the volume is 0.066 L, and the temperature is 298 K. When the temperature is changed to 308 K and the pressure remains constant, what is the new volume of the balloon?
Wednesday, April 20, 2016 by Dominique

Chemistry
if the pressure on a 1.00 L sample of gas is increased from 760. mm Hg to 2.00 atm at constant temperature what will the volume of the gas sample
Wednesday, April 20, 2016 by Harper

physics, english, chemistry, maths
A girl whose mass 404g walk up a flight of 20steps each 150mm height in 10s find the average power developed Hint g = 10m/S
Wednesday, April 20, 2016 by ellah

Chemistry-Dr.Bob222
A 25.0 mL sample of 0.125 M pyridine is titrated with 0.100 M HCl. Calculate the pH at 0 mL of added acid.
Tuesday, April 19, 2016 by Nevaeh

Chemistry
The pH of human blood needs to be between 7.35 and 7.45. You want to prepare a buffer solution that gives a pH of 7.40. You decide to use a sodium phosphate buffer: the acid is H2PO−4 and the conjugate base is HPO2− 4. You want the concentration of the acid to be 0...
Tuesday, April 19, 2016 by Emily

Chemistry
To completely react 17g of barium hydroxide, how many grams of hydrochloric acid is needed?
Tuesday, April 19, 2016 by Ellen

Chemistry
Assuming the solution you used was 95% ethanol by volume and that the density of ethanol is 0.816g/mL, how much water and carbon dioxide are produced in the experiment? Equation: C2H6O+3O2-->2CO2+3H2O
Tuesday, April 19, 2016 by BUTCHER

Chemistry
Two electron configuration: Mg(Ne)3s^2 Zn(Ar)4s^2 3d^10 Using the configurations, explain the difference in relative reactivity of the 2 metals ( which are Mg and Zn)
Tuesday, April 19, 2016 by Rose

Chemistry
Estimate the value of the equilibrium constant at 500 K for each of the following reactions. 2H2S(g)⇌2H2(g)+S2(g) I have calculate my delta H which is 168.9 kj/mol but I don't know where to go from there
Tuesday, April 19, 2016 by JoAnna

pre-ap chemistry
how to make 100 mL of a 0.500 M CuSO4 solution
Tuesday, April 19, 2016 by Anonymous

Chemistry
Will 1 L of 1 M NaCl contain more chloride ions than .5L of 1M MgCl2? Explain.
Tuesday, April 19, 2016 by Jordan

Chemistry
If a tire can hold 19L of air at 175 kPa and 25° C, what volume of air can the tire hold at 215 kPa and 30° C? Possible answers: A. 13.7 L B. 15.7L C. 23.0L D. 19L
Tuesday, April 19, 2016 by Anonymous

Chemistry
Two electron configuration: Mg(Ne)3s^2 Zn(Ar)4s^2 3d^10 Using the configurations, explain the difference in relative reactivity of the 2 metals ( which are Mg and Zn)
Tuesday, April 19, 2016 by Rose

Chemistry
The ions Cr3+ and O2- combine to form the ionic chromium oxide. in what proportions do these ions combine to produce a neutral compound?
Tuesday, April 19, 2016 by Monica

Chemistry
Which pair of compounds will form a solution?Benzene (C6H6) and hexane (C6H14)Na2SO4 and benzene (C6H6)NaCl and hexane (C6H14)H2O and CCl4More than one of the combinations above will form solutions.
Tuesday, April 19, 2016 by Kelly

Chemistry
Name two solutions that can be used to precipitate out the following: PbCl2 Would I just use a random soluble compound and write a total ionic equation
Tuesday, April 19, 2016 by AlphaPlus

Chemistry
What mass of sodium phosphate is needed to produce 75.00 g of solid product?
Tuesday, April 19, 2016 by Shania

Chemistry
Two electron configuration: Mg(Ne)3s^2 Zn(Ar)4s^2 3d^10 Using the configurations, explain the difference in relative reactivity of the 2 metals ( which are Mg and Zn)
Tuesday, April 19, 2016 by Rose

chemistry
Calculate the standard entropy change for the reaction of calcium oxide with water to form calcium hydroxide: CaO(s) + H2O(ℓ) → Ca(OH)2(s) at 298 K. ∆S ◦ m ∆H◦ f J K·mol? kJ mol? CaO(s) 39.75 −635.09 H2O(ℓ) 69.91 −...
Tuesday, April 19, 2016 by Anonymous

Chemistry
Balance the reaction step-wise: As2S3(s) + NO3^- + H^+(aq) to AsO4(aq) + S(s) + NO(g) + H2O(l)
Tuesday, April 19, 2016 by Subhan

Chemistry
If a half life of a radioactive element is twelve years,find the decay constant
Tuesday, April 19, 2016 by Undie vickvieny

Chemistry
In a student's experiment, when 40 mL of 6% (w/w) hydrogen peroxide solution was reacted with 10 mL 0.5 M FeCl3 solution, a ΔrH of -3,382 J was calculated. Calculate ΔH for this reaction in kJ mol-1. Give your answer to 2 decimal places, do not include the units ...
Tuesday, April 19, 2016 by Anon

Chemistry
Use the collision theory to explain the increase in rates of the other reactions
Tuesday, April 19, 2016 by Rose

Chemistry - Oxidation-Reduction reactions
how would your calculation of the molarity of KMnO4 be affected if you had added twice as much sulfuric acid and water as was called for in the procedure?
Tuesday, April 19, 2016 by Anonymous

Chemistry
t takes 572 kJ of energy to decompose 2.00 mol of liquid water. How much energy does it take to decompose 54.0 mol of water? 2H2O(l)+572kJ→2H2(g)+O2(g)
Monday, April 18, 2016 by Josh

Chemistry
The estimated proven world oil reserves in 2013 were 1526 billion barrels. The world annual rate of use was 32.6 billion barrels. How long will these reserves last if this rate of use continues? (The rate of use is actually likely to increase.)
Monday, April 18, 2016 by Josh

Chemistry
Burning 2.00 mol of hydrogen releases 483.6 kJ of energy. Determine how much energy, in kilojoules, must be supplied to convert 5.00 mol of water vapor into hydrogen gas and oxygen gas.
Monday, April 18, 2016 by Josh

chemistry
Determine delta G naught at 298.15K for a 0.50 V voltaic cell if n=3 for that cell.
Monday, April 18, 2016 by Kaitlin

Chemistry
What is the molar solubility of Mg(OH)2 in a solution containing 0,10 M NH3 ? Ksp Mg(OH)2 = 1.2x10^-11 Kp NH3 = 1.8x10^-5
Monday, April 18, 2016 by Kevin

Chemistry
What is the molar solubility of Mg(OH)2 in a solução containing 0,10 M NH3 ? Ksp Mg(OH)2 = 1.2x10^-11 Kp NH3 = 1.8x10^-5
Monday, April 18, 2016 by Kevin

Chemistry
The molar solubility of a generic substance, Mg(OH)2 ksp = (1.2x10^-11) in 0.10 M NH3 Kb = 1.8 x 10^-5 help me please =)
Monday, April 18, 2016 by Damon

Chemistry
A 50 g piece metal is placed in 250 g of methanol at 0 °C. The methanol is warmed to a temperature of 5 °C. What is the specific heat of the metal?
Monday, April 18, 2016 by Mary

Chemistry
Could someone please help guide me through this question: A 1.047 g sample of He(g) is found to occupy a volume of 8.446 L when collected over hexane at 25.0 ∘C and 739.6 mmHg barometric pressure. Use these data to determine the vapor pressure of hexane at 25 ∘C.
Monday, April 18, 2016 by Rima

Chemistry
Calculate the boiling temperature of a 0.50 M solution of sucrose. Assume that the concentration is 0.50 m.
Monday, April 18, 2016 by Caleb

Chemistry
Write balanced reaction for the following metal acid reaction A) Mg and HCI B) Zn and HCI
Monday, April 18, 2016 by Rose

AP Chemistry
Consider the following reaction: PbCl2 + 2 NaOH → Pb(OH)2 + 2 NaCl What would be the major species observed floating in solution after one mole of PbCl2 and 2 moles of NaOH are mixed in aqueous solution? 1. Na+ ions, Cl− ions and H+ ions 2. Pb2+ ions, Cl− ...
Monday, April 18, 2016 by Sam

chemistry
0.717g of potassium dihydrogen phosphate in 500ml concentration in ppm
Monday, April 18, 2016 by junaid

chemistry
Consider the equilibrium reaction CO(g)+H2O(g)⇋CO2(g)+H2(g) Determine how each change in the left-hand column will stress the system and in which direction the equilibrium reaction will shift in response.
Monday, April 18, 2016 by Jean

chemistry
commercially available concentrated hydrochloric acid is 37.0% w/w HCl. Its density is 1.18 g/mL. Using this information calculate (a) the molarity of concentrated HCl, and (b) the mass and volume (in mL) of solution containing 0.315 moles of HCl.
Monday, April 18, 2016 by Anonymous

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