Tuesday
May 31, 2016

Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

Chemistry
When an aqueous solution of sodium hydroxide, NaOH, is added to an aqueous solution of chromium(III) nitrate, Cr(NO3)3, a precipitate of chromium(III) hydroxide, Cr(OH)3, forms. Write a balanced net ionic equation for this reaction.
Tuesday, March 1, 2016 by Tina

Chemistry
How is 4FeS2 + 11O2 = 2Fe2O3 +8SO2 a single replacement reaction?
Tuesday, March 1, 2016 by Gary

Chemistry
A 0.10M solution of a certain monoprotic weak acid has a pH of 2.44. Calculate Ka.
Tuesday, March 1, 2016 by Jackson

Chemistry (stoichiometry)
22 moles of benzene are completely reacted with molecular oxygen, how many moles of carbon dioxide will be produced? and if 150 grams of water were produced, how many moles of oxygen must have reacted
Tuesday, March 1, 2016 by Alex

Chemistry- Dr.Bob
What is the final temperature and physical state of water when 250 grams of water at 85 degrees C is added to 80.0 grams of ice at -15 degree C? Is the physical state of water liquid? The explanation from bobpursly was this The sum of heats gained =0 80(cice)(0+15)+80Hf+80cw(...
Tuesday, March 1, 2016 by Student

Chemistry-Dr.Bob 222
What is the final temperature and physical state of water when 250 grams of water at 85 degrees C is added to 80.0 grams of ice at -15 degree C? Is the physical state of water liquid? I still don't understand how to do this.
Tuesday, March 1, 2016 by Student

Chemistry
Please sir solve this... 6.3 gm of oxalic acid (eq. Wt.=63) is dissolved in 500 ml solution what will be the normality of the solution?
Tuesday, March 1, 2016 by Pradeep

Chemistry
I was given a list of 14 different solutions, and My homework question asks which of the solutions exhibit the common-ion effect and which ones are buffers? But, how would I be able to tell???
Monday, February 29, 2016 by CeCe

Chemistry (Food)
Which of the following are B vitamins? Check ALL that apply. A). ascorbic acid B). retinol C). calciferol D). thiamine E). niacin
Monday, February 29, 2016 by Dominick

Chemistry
In the voltaic cell that is represented as: Cu | Cu2+ || Fe | Fe2+. The only anion in solution in the cells and salt bridge is the nitrate ion. The directions the electron external circuit and NO3- flow in the salt bridge circuit will be: *electron flow is Fe to Cu *electron ...
Monday, February 29, 2016 by Mikah

Chemistry
The three substances that can reduce Ag+ to Ag, but will not reduce Sn2+ to Sn are Zn, Pb, H2, Mg, Cu, I2, Al, Ca
Monday, February 29, 2016 by Taylor

Chemistry (Food)
The average energy yield per gram of carbohydrate and of fat is A).4 kcal and 9 kcal, respectively B).9 kcal and 4 kcal, respectively C).9 kcal each D).4 kcal each
Monday, February 29, 2016 by Dominick

Chemistry
what type of reaction occurs in Al+SnCl4 ? and what is the balanced equation
Monday, February 29, 2016 by Camila

Chemistry
What is delta h for reaction between h2o2 and ethene to give ethylene glycol if HO-OH is 49 kcal/mol and C=C 65 kcal/mol Please show ur work
Monday, February 29, 2016 by Brahamanand

Chemistry
I need major help with balancing redox reactions. I can't seem to get this one: (in basic conditions) NBr_3(aq)=> N_2(g) + Br^-(aq) + HOBr(aq) I don't know how to split this up properly, and when I do it is like impossible to balance it. Thanks!
Monday, February 29, 2016 by Betty

Chemistry
What is the final temperature and physical state of water when 250 grams of water at 85 degrees C is added to 80.0 grams of ice at -15 degree C? Is the physical state of water liquid? I don't understand the set up. The setup is like this (answered by bobpursly): The sum of...
Monday, February 29, 2016 by Student

Chemistry
CH4 (g)+ H2O (g) --->/<---- 3H2 + CO Use Le Chateliers Principle to explain what will happen to the number of moles of hydrogen at equilibrium when a) CO is removed b) Water Vapor is removed c) Methane is added d) CO is added e) Pressure is increased by adding argon gas...
Monday, February 29, 2016 by Student

Chemistry... again
How does a polar bond differ from a nonpolar bond? Explain your answer. All I need are ideas, not the word-for-word answer.
Monday, February 29, 2016 by Leet Speaker

Chemistry
Highest ionization energy to lowest I be ci f
Monday, February 29, 2016 by Anonymous

Chemistry
If you make a solution in the laboratory that contains 0.1 M acetic acid (CH3COOH), what concentration of hydronium will you have once the solution equilibrates?
Monday, February 29, 2016 by Rose

Chemistry
If you make a solution in the laboratory that contains 0.1 M hydrochloric acid, what concentration of hydronium will you have?
Monday, February 29, 2016 by Rose

chemistry
1. what mass of sodium hydroxide is required to make up 100 mL of 0.5000M solution 2.What volume of this solution must be diluted down to 100 mL if 0.100M solution of NaOH is required?
Monday, February 29, 2016 by Anonymous

Some Chemistry Questions
I got three questions. If you were making a tool used to handle live electrical wires, which class of materials would you most likely use? ***Semimetals Metalloids Nonmetals Metals Which of the following changes gives no evidence that a chemical reaction has taken place? A ...
Monday, February 29, 2016 by Leet Speaker

Chemistry
what is the concentration of each substance if a solution is prepared by mixing 5.00g of NaC2H3O2 with 15.0 ml of 1.45M acetic acid and then bringing the total volume to 250.0 ml?
Monday, February 29, 2016 by Ali

Chemistry
CH4 (g)+ H2O (g) --->/<---- 3H2 + CO Use Le Chateliers Principle to explain what will happen to the number of moles of hydrogen at equilibrium when a) CO is removed b) Water Vapor is removed c) Methane is added d) CO is added e) Pressure is increased by adding argon gas...
Monday, February 29, 2016 by Student

Chemistry
What is the final temperature and physical state of water when 250 grams of water at 85 degrees C is added to 80.0 grams of ice at -15 degree C? Is the physical state of water liquid? I don't understand the set up that I have to set the equation equal to 0 ...
Monday, February 29, 2016 by Student

Chemistry
The pH of a 0.095 M solution of an unknown monoprotic acid is 5.42. Calculate the Ka of the acid. A) 3.8 x 10-6 B) 3.6 x 10-7 C) 1.5 x 10-10 D) 2.6 x 10-9 E) 2.8 x 10-8 ​
Monday, February 29, 2016 by Bronwyn

Chemistry
I got 1.11 x 10^-6 for K. Here is my work: x= 0.004 -2x= -0.008 (change for CH4) Equilibrium for CH4 is 0.087 - 0.008= 0.079 Change in eq for C2H2 is 0.004 and eq is 0.004 (=x) Change in eq for H2 is 0.012 Eq for H2 is 0.012 K= [C2H2][H2]^3/[CH4]^2 K= (0.004)(0.012)^3/(0.079)^...
Monday, February 29, 2016 by Student

Chemistry
What is the value of the equilibrium constant for the overall reaction? ​​ AgCl (s) + 2NH3 (aq) Ag(NH3)2+ (aq) + Cl- (aq) Knet = ?
Monday, February 29, 2016 by Bronwyn

Chemistry
How many milliliters of 2.00 M NaHO solution are needed to neutralize a 8.00 mL of 3.50 M H2SO4 solution?
Monday, February 29, 2016 by Hailey

Chemistry
I need to write a hypothesis on limiting reactants.
Monday, February 29, 2016 by Keron

cHEMISTRY
What mass of AgCl(143.32g/mol) is formed from the reaction of a 0.109 M MgCl2 solution with excess AgC2H3O2?
Monday, February 29, 2016 by lIZ

Organic Chemistry
Hello, I have done an experiment in Organic Chemistry called :SN1 Reaction: Synthesis of t-amyl chloride from t-amyl alcohol, there are some questions that I am unsure about, 1) What are the 2 rules of HCl in this reaction? Can you use NaCl instead of HCl to synthesize t-amyl ...
Monday, February 29, 2016 by Mohammed

Chemistry
calculate the bond energy for diatomic oxygen O2 given that standard enthalpy of atomization of oxygen (ΔH) = 249.17KJ
Monday, February 29, 2016 by Solomon

Chemistry
The reaction of CH4 in 2CH4(g) ---->/<---- C2H2(g) + 3 H2 (g) is carried out at a different temperature with an initial concentration of [CH4]=0.087M. At equilibrium, the concentration of H2 is 0.012 M. Find the equilibrium constant at this temperature.
Sunday, February 28, 2016 by Student

chemistry
A solution containing 29.00 mg of an unknown protein per 22.0 mL solution was found to have an osmotic pressure of 3.10 torr at 18 ∘C. What is the molar mass of the protein? (3.10 torr* 22mL)=.682 I do not know what to do next
Sunday, February 28, 2016 by mmp

Chemistry
What volume (in milliliters) of 0.170 M NaOH should be added to a 0.140 L solution of 0.021 M glycine hydrochloride (pKa1 = 2.350, pKa2 = 9.778) to adjust the pH to 2.84? I tried using the Henderson- Hasselbalch equation but I am confused about what to do with the answer to ...
Sunday, February 28, 2016 by L

Chemistry
I did a lab, an kinetics lab (iodide clock) and in my lab report I have to calculate the initial rate in mol L-1 s-1 and I'm not sure how to do that. I have the [I-] and [S2O82-] in mol L-1 already. The reagents are [KI] [NaCl] [Na2S2O3] [Na2SO4] [K2S2O8].
Sunday, February 28, 2016 by Dan

Chemistry
Help! I have to get this done tonight and I cannot get this answer right. A solution of water (Kf=1.86 ∘C/m) and glucose freezes at − 3.55 ∘C. What is the molal concentration of glucose in this solution? Assume that the freezing point of pure water is 0.00 &#...
Sunday, February 28, 2016 by Emmalee

Chemistry
A 70.0 mL solution of 0.171 M potassium alaninate (H2NC2H5CO2K) is titrated with 0.171 M HCl. The pKa values for the amino acid alanine are 2.344 (pKa1) and 9.868 (pKa2), which correspond to the carboxylic acid and amino groups, respectively. a) Calculate the pH at the first ...
Sunday, February 28, 2016 by Bobby

Chemistry
What volume (in milliliters) of 0.100 M NaOH should be added to a 0.120 L solution of 0.024 M glycine hydrochloride (pKa1 = 2.350, pKa2 = 9.778) to adjust the pH to 2.95? I dont know how to do this problem! Steps with answers please!! HELP!!
Sunday, February 28, 2016 by Bobby

SCIENCE
jamal's neighbor tells him that there are more bacterial cells than human cells in his body. which of these is the best reason that jamal should question his neighbors statement? a. jamal is older than his neighbor b. jamal does not like his neighbor very much. c. his ...
Sunday, February 28, 2016 by John Doswell

Chemistry
When 50 grams of hydrocarbon X are burned with oxygen the products are carbon dioxide and water. If 65 grams of water and 100 grams of carbon dioxide are produced, how many grams of oxygen were needed for the reaction? This was a question on my chemistry homework but I'm ...
Sunday, February 28, 2016 by Ryan

Science Help
jamal's neighbor tells him that there are more bacterial cells than human cells in his body. which of these is the best reason that jamal should question his neighbors statement? a. jamal is older than his neighbor b. jamal does not like his neighbor very much. c. his ...
Sunday, February 28, 2016 by John Doswell

Chemistry
In a volumetric analysis experiment, a solution of sodium oxalate in acidic soltuion is titrated with a solution of potassium permanganate according to the following balanced chemical equation: 2KMnO4+8H2SO4+5Na2C2O4 -> 2MnSO4+8H2O+10CO2+5Na2SO4+K2SO4 What volume of .0239 M...
Sunday, February 28, 2016 by Kaley

Chemistry
What is the strongest intermolecular force present in each molecule: H2S CF4 NH3 CS2 PCL3 N CH2O C2H6 CH3OH BH3 My work: Hydrogen bonding London dispersion Dipole dipole London dispersion Dipole dipole London dispersion Hydrogen bonding Hydrogen bonding Hydrogen bonding Am I ...
Sunday, February 28, 2016 by Rose

chemistry
what would be observed when combining an aqueous mixture of: potassium carbonate and hydrochloric acid, zinc chloride and silver nitrate, magnesium chloride and sodium hydroxide, ammonium nitrate and sodium hydroxide?
Sunday, February 28, 2016 by sarah

chemistry
The standard internal energy change for a reaction can be symbolized as ΔU°rxn or ΔE°rxn. For the following reaction equations, calculate the energy change of the reaction at 25 °C and 1.00 bar. Sn(s) + 2Cl2(g) --> SnCl4(l) ΔH°rxn = -511.3 kJ/...
Sunday, February 28, 2016 by jake

chemistry
1.what are the functions of pH?
Sunday, February 28, 2016 by sarah

Chemistry
Why a benzene ring sometimes gives -I effect? Why is No2 is more electron withdrawing then CN?
Sunday, February 28, 2016 by Anand rajput

Chemistry
If milk is refrigerated in containers of glass, plastic and cardboard, in which container to you believe the milk will have the most increase in lactic acid?
Sunday, February 28, 2016 by Jennifer

chemistry
calculate joules release when 175g of steam condenses at 100c and cool the liquid to 35.00c
Saturday, February 27, 2016 by linda

Food Chemistry
A heat exchanger is used to warm apple cider using steam as the heat source. The cider is heated from an initial temperature of 4°C to a final temperature of 65°C. The steam enters the heat exchanger as 50% quality steam and exits as water condensate at 85°C. ...
Saturday, February 27, 2016 by Ashwaa

Chemistry
Write the balanced equation for the neutralization reaction between H3PO4 and NaOH in aqueous solution. Phases are optional.
Saturday, February 27, 2016 by Dane

Chemistry
What is the molarity of a solution that results when 3.64 g KCl is dissolved in water and diluted to exactly 200.0 mL?
Saturday, February 27, 2016 by Van

Chemistry
I have to summarize 10 articles relating to the topics we had covered in class. However, there are 3 sources out of the 10 that I don't understand. Could someone possibly go through the sources and summarize them. 1.) This article covers Nuclear Chemistry (Nuclear Reactors...
Saturday, February 27, 2016 by Jess

analytical chemistry
what is the volume that must be added to dillute 20.0 ml of 0.1M Hcl to 0.02M Hcl
Saturday, February 27, 2016 by francime

Chemistry
An interference filter is to be constructed for isolation of the nitrobenzene absorption band at 1537 cm-1. (a) If it is to be based on first-order interference, what should be the thickness of the dielectric layer (refractive index of 1.34)? (b) What other wavelengths would ...
Saturday, February 27, 2016 by Aaron

Chemistry
Calculate the volume of hydrogen produced at s.t.p when 25g of zinc are added to excess dilute hydrochloric at 3degree and 778mmhg pressure
Saturday, February 27, 2016 by Jubilee

Chemistry
If 10.0 L of hydrogen collected over water at 20' C and 750 mm Hg are produced, how many grams of iron metal must react with excess steam?
Saturday, February 27, 2016 by Yoni

Chemistry
Hi! I'm having trouble solving this question, not sure how to go about starting it: Magnalium is a solid mixture of aluminum metal & magnesium metal. An irregular shaped chunk of a sample of magnalium is weighed twice, once in air (211.5g) and once in vegetable oil (135.3g...
Friday, February 26, 2016 by Mila

chemistry
The formula for rust can be represented by Fe2O3. How many moles of Fe are present in 27.6 g of the compound?
Friday, February 26, 2016 by jessie

Chemistry
An interference filter is to be constructed for isolation of the nitrobenzene absorption band at 1537 cm-1. (a) If it is to be based on first-order interference, what should be the thickness of the dielectric layer (refractive index of 1.34)? (b) What other wavelengths would ...
Friday, February 26, 2016 by Joseph

Chemistry
For the gratings (84.0 lines per millimeter and 15.0 mm of illuminated area) calculate the wavelengths on the first and second-order diffraction spectra at reflective angles of (a) 20 degrees and (b) 0 degrees. Assume the angle of incidence is 45 degrees.
Friday, February 26, 2016 by Joseph

Chemistry
what is the oxidation number of Chlorine in KCIO4???
Friday, February 26, 2016 by kevin

Chemistry
27% of heat produced by the stove's gas burner is transferred to the soup in the covered pot, the rest is lost. Determine the total mass in grams of methane that must be burned to heat 800 ml of water from 22 to 90 degrees C. The density is 1.08 g/ml and the specific heat ...
Friday, February 26, 2016 by Dan

Chemistry
What will be the volume of ammonia formed from 2L of nitrogen and 2L of hydrogen
Friday, February 26, 2016 by Mohammed

chemistry
I need help. I have no clue how to find this. A flask is charged with 1.680 atm of N2O4(g) and 1.220 atm of NO2(g) at 25 degrees celcius. The equilibrium reaction is N2O4 <-> 2 NO2 After equilibrium is reached, the partial pressure of NO2 is 0.550 (a) What is the ...
Friday, February 26, 2016 by Alexus

Chemistry
Calculate the entropy change accompanying conversion of 1 mole of ice at 273 K and 1 atm pressure into steam at 373 K and 1 atm pressure, given that at 273 K, the molar heat of fusion of ice is 6 kJ/mol and at 373 K, the molar heat of vapourization of water is 40.60 kJ/mol. ...
Friday, February 26, 2016 by Mahesh

chemistry
Imagine that you have a 5.50 L gas tank and a 3.50 L gas tank. You need to fill one tank with oxygen and the other with acetylene to use in conjunction with your welding torch. If you fill the larger tank with oxygen to a pressure of 155 atm , to what pressure should you fill ...
Friday, February 26, 2016 by lily

Chemistry
Calculate the mass in grams present in 0.95 mole of sodium hydrogen trioxocarbonate(iv)
Thursday, February 25, 2016 by Hukay baso

Chemistry
If a metal ore contains 22.5% pure metal, how many pounds of pure metal can be obtained from 79 pounds of metal ore? Answer in units of pounds.
Thursday, February 25, 2016 by Hector

Chemistry
A chemist needs a 50% of sulfuric acid. She mix 2 liters of 20% of sulfuric acid with a sample of 60% of sulfuric acid. Write a equatoin that models the situation and use it to find how much the 50% of the sulfuric acid she needs to use?
Thursday, February 25, 2016 by James

Chemistry
The balanced reaction equation for the combustion of heptane, C7H16, is given below. If the reaction produced 37.5 g CO2, how many grams of heptane were burned?
Thursday, February 25, 2016 by Veronique

Chemistry
Consider the following reaction: CO2 (g) + H2 (g) CO (g) + H2O (g) Calculate the value of the equilibrium constant, Kc, for the above system, if 0.1908 moles of CO2, 0.0908 moles of H2, 0.0092 moles of CO, and 0.0092 moles of H2O vapour were present in a 2.00 L reaction vessel...
Thursday, February 25, 2016 by kevin

Chemistry
2. Does a precipitate of silver chloride form when 200.0 mL of 1.0 x 10-4 M AgNO3 (aq) and 900.0 mL of 1.0 x 10-6 M KCl (aq) are mixed at 25oC?[ Ksp AgCl @ 25oC = 1.6 x 10-10]
Thursday, February 25, 2016 by kevin

Chemistry-nudge the
A 4.30 g nugget of pure gold absorbed 298 J of heat. The initial temperature was 22.0°C. What was the final temperature? °C
Thursday, February 25, 2016 by Karla

Chemistry
A 4.30 g nugget of pure gold absorbed 298 J of heat. The initial temperature was 22.0°C. What was the final temperature? °C
Thursday, February 25, 2016 by Karla

Chemistry
Why is methanol a good solvent to recrystallize biphenyl?
Thursday, February 25, 2016 by Danny

Chemistry
Calculate how many grams of FeSO4.7 H2O (MW = 278.02 g/mol) will be needed to prepare 1 mL of a 0.2 M FeSO4 solution? Is that .0304g?
Thursday, February 25, 2016 by Feufolia

Chemistry
What functional group(s) does 4-Ethylphenol have? I know it has an alcohol. Should I also say that it has an arene?
Thursday, February 25, 2016 by Anonymous

Chemistry
Calculate how many grams of FeSO4 . 7 H2O (MW = 278.02 g/mol) will be needed to prepare 1 mL of a 0.2 M FeSO4 solution? Am I right when I say we'd need
Thursday, February 25, 2016 by Feufolia

Chemistry 101
If gold sells today for 1625 per ounce, and a large mining truck hauls 400 tons of gold ore, what is the value of the gold in each truck if each ton of gold ore contains 1.0 ounces of gold? Use dimensional analysis.
Thursday, February 25, 2016 by Lilly

Chemistry 101
If gold sells today for 1625 per ounce, and a large mining truck hauls 400 tons of gold ore, what is the value of the gold in each truck if each ton of gold ore contains 1.0 ounces of gold? Use dimensional analysis.
Thursday, February 25, 2016 by Lilly

Chemistry
If 0.30 mol N2H4 is reacted with 0.50 mol N2O4, how many moles of N2 can be formed?
Thursday, February 25, 2016 by Christian

chemistry
Write the chemical equation that oxidize oxalic acid to carbon dioxide and water
Thursday, February 25, 2016 by james

COLLEGE,CHEMISTRY
CH3-C-CH3=CH2+H-OH-->
Thursday, February 25, 2016 by RINTU

Chemistry
Why are liquids that are refrigerated and stored in glass always colder than those refrigerated and stored in plastic or cardboard?
Thursday, February 25, 2016 by Ali

Chemistry
How does salt hydrolysis work between sodium hydroxide and lactic acid in a titration?
Thursday, February 25, 2016 by Hannah

chemistry
___Fe(NO3)2 + Al___Al(NO) +__Fe
Wednesday, February 24, 2016 by Sabrina

Chemistry
Find the mass of urea (CH4N2O) needed to prepare 50.9 g of a solution in water in which the mole fraction of urea is 7.69×10−2.
Wednesday, February 24, 2016 by Nicole

Chemistry
a solution is prepared by dissolving 15.0 grams of ni(no3)2 in enough water to make 250 ml of solution what is the molarity of this solution
Wednesday, February 24, 2016 by Madison

Chemistry
C+H2O ARROW CO+H2
Wednesday, February 24, 2016 by C+H2O ARROW CO+H2

Chemistry
how does one go about finding the Tf of this equation 100Hf+100cw(Tf-0) + 300w(Tf-25) =0 and can you also explain what cw and Hf mean? i have no idea.
Wednesday, February 24, 2016 by Student

Chemistry
I have to write the rate law for two elementary reaction equations A ) 2a+b>c+d B ) X+Y>Z I'm pretty sure it's just k[ A ][ B ] and k[ X ][ Y ] but does the coefficient affect it in this case? is it [ A ]^2 ?
Wednesday, February 24, 2016 by Dan

Chemistry
PART 1 >>Trial 1 Reactant Solution A 10 ml I^-, 5.0 ml S2O3^2- Reactant Solution B 10 ml S2O8^2-, 1 ml starch time to react = 10 seconds >>Trial 2 Reactant Solution A 10 ml I^-, 5.0 ml S2O3^2- Reactant Solution B 5 ml S2O8^2-, 1 ml starch time to react = 20 seconds...
Wednesday, February 24, 2016 by Dan

Chemistry
Suppose that 100.0 g of ice a 0 degreesC are added to 300.0 g of water at 25.0 degrees . Is this sufficient ice to lower the temperature of water to 5.00 degrees C and still have ice remaining? Calculate the energy (heat) which must be removed from water to achieve the desired...
Wednesday, February 24, 2016 by Sage

Chemistry
What is the final temperature and physical state of water when 250 grams of water at 85 degrees C is added to 80.0 grams of ice at -15 degree C? Is Tf= 109 C? Is it in the steam phase?
Wednesday, February 24, 2016 by Student

Chemistry
if 9560 J of energy were absorbed by 25.0g of ice at 0 degrees Celsius what would be the final temperature? First you must calculate the energy required to melt ice completely. With the remaining energy (Q). This is the equation i came up with but i'm not even sure if its ...
Wednesday, February 24, 2016 by Sage

Chemistry
PART 1 >>Trial 1 Reactant Solution A 10 ml I^-, 5.0 ml S2O3^2- Reactant Solution B 10 ml S2O8^2-, 1 ml starch time to react = 10 seconds >>Trial 2 Reactant Solution A 10 ml I^-, 5.0 ml S2O3^2- Reactant Solution B 5 ml S2O8^2-, 1 ml starch time to react = 20 seconds...
Wednesday, February 24, 2016 by Dan

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Homework Help: Science