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February 21, 2017

Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

Chemistry
If a box contain 256 water molecules and 1 Na+ ion , then what will be the Molarity of the solution.
Tuesday, November 29, 2016 by Robin Jain

chemistry
Identify the species oxidized, the species reduced, the oxidizing agent and the reducing agent in the following electron transfer reaction. 2Fe3+ + Sn2Fe2+ + Sn2+ species oxidized species reduced oxidizing agent reducing agent As the reaction proceeds, electrons are ...
Tuesday, November 29, 2016 by LaMetria

chemistry
The following information is given for ether, C2H5OC2H5, at 1atm: boiling point = 34.6 °C Hvap(34.6 °C) = 26.5 kJ/mol specific heat liquid = 2.32 J/g°C At a pressure of 1 atm, kJ of heat are needed to vaporize a 41.0 g sample of liquid ether at its normal boiling point of ...
Tuesday, November 29, 2016 by LaMetria

Chemistry
If the change in temperature of a sugar added solution of water increased its boiling point by 0.6C how many moles of sugar was added to the water?
Monday, November 28, 2016 by Bill

Chemistry
A minimum energy of 151 kJ is required to dissociate a mole of iodine molecules, I2. Calculate the wavelength of radiation that supplies this energy, assuming each bond beaks by absorbing one photon.
Monday, November 28, 2016 by Victor

Chemistry
The maximum number of PbO molecules that can be injected is 3.01 x 10*23 1.) How many moles of PbO can be injected? 2.) What mass of PbO can be injected?
Monday, November 28, 2016 by Nayer

Chemistry
Which of the following gases has the highest average speed at 400K? NO2 OF2 SO2 SF6
Monday, November 28, 2016 by Kanye

Chemistry
At 298 K which is larger rate of effusion or rate of diffusion?
Monday, November 28, 2016 by Kanye

Chemistry
A 5.00-L flask contains nitrogen gas at 25°C and 1.00 atm pressure. What is the final pressure in the flask if an additional 2.00 g of N2 gas is added to the flask and the flask cooled to -55°C?
Monday, November 28, 2016 by Kanye

Chemistry
If 3.42 grams of Al2(SO4)3 are required, what mass of H2SO4 must be present?
Monday, November 28, 2016 by Asia

Chemistry
Write an equation for the oxidation of NH2OH to HNO3 by KBrO3. Balance the reaction equation using the ion-electron method.
Monday, November 28, 2016 by Terry

Chemistry 20
Lab: Determining the Quantity of Vitamin C in Fruit Juice Vitamin C, also called ascorbic acid, is commonly found in commercial fruit juices and drinks. In this activity you will analyze data collected from a titration analysis of a fruit juice. The nutrition facts for a 200-...
Monday, November 28, 2016 by Sadie

Chemistry
If you try to carry out a double displacement reaction by mixing together equal volumes of a solution that contains dissolved NaF and a solution that contains dissolved NaCl. Would you expect a reaction? Why or why not?
Monday, November 28, 2016 by Rebecca

Chemistry
Hi, wondering if anyone can help with the following problem: A solution of NH3 (kb=1.8x10^-5) has a ph of 11. what is the molar concentration of NAOH? I am unsure how to go about this however i have tried [10^-3][10^-11]/ 1.8x10^-5 with no success. Thanks for your help
Monday, November 28, 2016 by Frank

chemistry
Calculate the formula of a compound which has composition. MaMagnesium 9.8%,sulphur 13%, oxygen 26%,water of crystallization 51%. (Mg=24,S=32,O=16,H2O=18g/mol)
Monday, November 28, 2016 by furry

Chemistry
Why we add HCL ot H2SO4 during the experiment Of iodometry?
Monday, November 28, 2016 by Mikel

chemistry
A bottle of cabernet sauvignon wine contains 12.5% v/v ethanol. How much ethanol will be present in a dozen 750 mL bottles of this wine?
Sunday, November 27, 2016 by r

Chemistry
I am trying to answer the question below, and I am guessing the reason lactate has a lower Km is that it is better able to accept electrons than ethanol. Is this correct? If so, what makes lactate a better electron acceptor? Any help is greatly appreciated! "ethanol is a very ...
Sunday, November 27, 2016 by Student

Chemistry
A sample of Chlorine occupies 8.50 L at 80.0 C and 740 mm Hg. What volume will Chlorine occupy at STP?
Sunday, November 27, 2016 by riley

Chemistry
I need to find the pH of a 500 mL solution of pure water after adding 33.0 mg of H2SO4 and 18.0 mg of HCl. Please help! So far I have tried to find the moles of 33.0mg of H2SO4 and got 3.24. Then I calculated pH by multiplying the subscript of H (2) by the moles (3.24) and ...
Sunday, November 27, 2016 by Nicole

chemistry
estimate the enthalpy change for the following reaction: OF2 + H2O = O2 + 2HF
Sunday, November 27, 2016 by small

Chemistry
What volume of hydrogen, reacting with nitrogen, will produce 500 dm^3 of NH3 at STP?
Sunday, November 27, 2016 by Emily

Chemistry
why does chlorobenzoic acid have a lower freezing point than benzoic acid explain? would this have something to do with the intermolecular forces or polarity. I know that the chlorobenzoic acid a Cl atom in the molecule which would create for a stronger intermolecular force ...
Sunday, November 27, 2016 by Sean

Chemistry
In Cl2 + 2KBr -> 2KCl and Br2 produce that brown yellow effect?
Sunday, November 27, 2016 by Sarah

chemistry
what is the purpose of using an ice bath in organic chemistry when isolating the final product?
Sunday, November 27, 2016 by Denaiel

Chemistry
What mass of calciumoxide is formed by heating Ca(iii)oxocarbonate(iv) when calcium = 40, carbon = 12, oxygen = 16
Sunday, November 27, 2016 by Tellyson

CHEMISTRY
HOW TO PREPARE 1 M GUAICOL FROM LIQUID GUAICOL SOLUTION MOLECULAR WEIGHT 124.14 DENSITY 1.11
Sunday, November 27, 2016 by ROSHAN

Chemistry
Among the solubility rules previously discussed is the statement: Carbonates, phosphates, borates, and arsenates—except those of the ammonium ion and the alkali metals—are insoluble. (a) Write the expression for the equilibrium constant for the reaction represented by the ...
Sunday, November 27, 2016 by Tammy

Chemistry
hen excess Ag metal is added to 0.246 L of 1.290 M Fe3+(aq) at 298K, the following equilibrium is established: Ag+(aq) + Fe2+(aq) Ag(s) + Fe3+(aq) (1) If the equilibrium concentration of Ag+ is 0.504 M, what is the value of K? K = (2) Using the value of K from part (1), ...
Sunday, November 27, 2016 by Shipaz

Chemistry
calculate the concentrations of H2S04, H30+, HSO4- and SO42- in 0.4 M H2S04 solution
Sunday, November 27, 2016 by Johnny

chemistry
why half cell reactions are given in reduction reations by IUPAC?
Sunday, November 27, 2016 by sadaf

Chemistry
What volume of 0.1244M hydrochloric acid is required to neutralize 24.81 ml of 0.1026M barium hydroxide? from the mole to mole ratio and the given information I came up with .00509 mols of HCl. would I multiply this by 0.1244 or divide by .1244. I'm not sure which would be ...
Saturday, November 26, 2016 by Sean

Chemistry
If there are 10 groups performing an experiment and each group needed 25.0 mL of 0.250 M NaOH, how would you prepare the NaOH solution for the whole lab using the NaOH pellets?
Saturday, November 26, 2016 by Mason Rutledge

chemistry
CH4+2O2-->CO2+2H2O If 22.75g of carbon dioxide is obtained when 9g of methane is burned in excess oxygen, what is the percent yield? Show work too please
Saturday, November 26, 2016 by help pls

chemistry
2Na+2H2O-->2NaOH+H2 what is the mass of reactant left over? pls show work too thank you
Saturday, November 26, 2016 by help pls

Chemistry
The equilibrium constant, K, for the following reaction is 1.54×10-2 at 506 K: PCl5(g) PCl3(g) + Cl2(g) An equilibrium mixture of the three gases in a 15.7 L container at 506 K contains 0.207 M PCl5, 5.64×10-2 M PCl3 and 5.64×10-2 M Cl2. What will be the concentrations of ...
Saturday, November 26, 2016 by Daniel

chemistry
Cu+HNO2-Cu(NO3)2+NO solved by oxidation no. Method
Saturday, November 26, 2016 by sakul

Chemistry
h2po4(aq) + co34(aq) hco3 (aq) + hpo42 (aq)
Friday, November 25, 2016 by Adam

chemistry
if i have an isopropyl group and the a carbon with a methyl group on it, will the methyl protons be split by the isopropyl protons? (CH3)2---C-C-(CH3)
Friday, November 25, 2016 by Anonymous

chemistry NMR helpppp
really really need some help, been stuck on this for toooo long. Some Data: "A" triplet for 3H (2 neighbors) "B" quartet for 2H (3 neighbors) "C" singlet for 3H (no neighbors) "D" singlet for 2H (no neighbors) Alright here is what i have so far: im trying to figure out what ...
Friday, November 25, 2016 by Anonymous

chemistry
The number of unpaired electrons and the element for [Xe]6s24f145d7: I know the element is Iridium but I cannot figure out the unpaired electrons!
Friday, November 25, 2016 by Jordan

Chemistry
the solubility of aspartic acid in water is .500 g in 100 mL at 25 degrees C. If .251 g of aspartic acid is dissolved in 50. mL of water at 50 degrees C and let solution cool to 25 degrees C. is the solution supersaturated, saturated, or unsaturated. the solution was not ...
Friday, November 25, 2016 by Nicole

Chemistry
Why does the white precipitation turns dark when adding Na2S2O3 drop wise to AgNO3 sollution
Friday, November 25, 2016 by Pramodi

Chemistry
A reaction of hydrolysis of Ba(NO) in a net ionic form?
Friday, November 25, 2016 by Patricia

Chemistry
How long must a steady current of 4.0A flow through the electrolyte to coat a a steel spoon with 8.5g of nickel?
Thursday, November 24, 2016 by Zoila

Chemistry
Carbohydrates (such as C6H12O6) undergo combustion with oxygen to produce carbon dioxide and water. Living things use this reaction (a process called respiration) to produce energy. Determine the mass of carbohydrates consumed for every 0.300 mol of oxygen gas consumed during ...
Thursday, November 24, 2016 by Ryan

Chemistry
Carbohydrates (such as C6H12O6) undergo combustion with oxygen to produce carbon dioxide and water. Living things use this reaction (a process called respiration) to produce energy. Determine the mass of carbohydrates consumed for every 0.300 mol of oxygen gas consumed during ...
Thursday, November 24, 2016 by Ryan

AP Chemistry
Calculate the concentration of the constituentions in solutions of the following compounds in the following concentrations: (a) 0.45 M HBr, (b) 0.045 M KOH, (c) 0.0112 M CaCl2.
Thursday, November 24, 2016 by Phoebe

Chemistry
In the dehydrogenation of ethane two reactions take place: C2H6 => C2H4 + H2 C2H6 + H2 => 2CH4 The mass distribution of the product is: 27% C2H6; 33% C2H4; 13% H2; 27% CH4. 1. What was the conversion of C2H6 to CH4? 2. What was the yield of C2H4 expressed in kg of C2H4 ...
Thursday, November 24, 2016 by Hoang

Analytical chemistry
Calculate the expected concentrations of vitamin B6 and caffeine in the stock solution assuming exactly 0.0506 g of pyridoxine hydrochloride (vitamin B6) and 0.1253 g of caffeine are dissolved in a 100 mL volumetric flask.
Wednesday, November 23, 2016 by Angel

Chemistry
How would I make a 93.1% w/w solution from 96% sulfuric acid using volume
Wednesday, November 23, 2016 by Pam

Chemistry
A 2.00L flask was filled with 4.00 mol of HI at a certain temperature and given sufficient time to react. At equilibrium the concentration of H2 was 0.400 M. Find the equilibrium concentrations of I2 and HI and then find the Keq at this temperature 2HI(g) <-> H2(g) + I2(g)
Wednesday, November 23, 2016 by Jessica

chemistry
normality of a solution containing 2g sodium carbonate in 250mL solution
Wednesday, November 23, 2016 by silpa

chemistry
give the name of the process when anhydrous copper sulphate becomes wet
Wednesday, November 23, 2016 by augustine

Chemistry
A 30.0 mL sample of 0.165 molL−1 propanoic acid (Ka=1.3×10−5) is titrated with 0.300 molL−1KOH. Calculate the pH at 0, 5,10, at equivalence point, 1/2 of the equivalence point, 20, 25 mL of added base.
Tuesday, November 22, 2016 by Sam Dowen

chemistry
Changing 1 mol of Mg(s) and 1/2 mol of O2 (g) to gaseous atoms requires a total of approximately 150kJ of energy. The first and second ionization energies of Mg are 737kJ/mol and 1450kJ/mol respectively. The first and second electron affinities of Oxygen are -141KJ/mol and +...
Tuesday, November 22, 2016 by Insolvable question

Chemistry
Before small batteries were available, carbide lamps were used for bicycle lights. Acetylene gas, C2H2, and solid calcium hydroxide were formed by the reaction of calcium carbide, CaC2, with water. The ignition of the acetylene gas provided the light. Currently, the same lamps...
Tuesday, November 22, 2016 by Andrew

chemistry
State whether each of the following sets of quantum numbers is permissible for an electron in an atom. If a set is not permissible, explain why. (i) [1, 0, +1/2, +1/2] and (ii) [3, 2, 1, 1]
Tuesday, November 22, 2016 by biman

Chemistry
A student followed the procedure given in the lab exercise to determine the ascorbic acid content in a commercial vitamin C tablet. The students prepared the solution using a 0.460 g vitamin C tablet. The titration required 40.00 mL of the 0.005 M KIO3/KI solution to reach an ...
Tuesday, November 22, 2016 by R

Chemistry
How many moles of air must be pumped into a 4.8 L tire to give it the pressure of 47.1 psi at 25°C ? I'm not sure how to even start doing this problem.
Monday, November 21, 2016 by Amanda

Chemistry
Is "a color of solution becoming less intense due to dilution" maybe evidence of chemical reaction or not?
Monday, November 21, 2016 by Anonymous

Chemistry
Carbohydrates (such as C6H12O6) undergo combustion with oxygen to produce carbon dioxide and water. Living things use this reaction (a process called respiration) to produce energy. Determine the mass of carbohydrates consumed for every 0.300 mol of oxygen gas consumed during ...
Monday, November 21, 2016 by Ryan

Chemistry
8.8 g of iron(II) sulphide reacts completely with excess dilute hydrochloric acid. Calculate the volume of hydrogen sulphide evolved, measured at 18 º C and 729 mmHg pressure.
Monday, November 21, 2016 by Christopher Penner

Chemistry
A sample of carbon monoxide was collected over water at a total pressure of 752 torr and a temperature of 15°C. What is the pressure (in torr) of the carbon monoxide?
Monday, November 21, 2016 by Andrew

Chemistry Lab
So I have a lab exam tomorrow and our instructor said that one of the questions would be as follows: Prepare 100mL of 0.03 M Copper Sulfate, beginning from copper sulfate pentahydrate. Calculate the exact molarity to 3 sig figs. Alright so I understand how to prepare 100mL of ...
Monday, November 21, 2016 by Jake

Chemistry 20
a source of hydrogen is an important issue of hydrogen fuel cells are going to become useful in automobiles. What important perspective is missing?
Monday, November 21, 2016 by David

Chemistry 20
If 4.56 mol of zinc react with excess copper (ii) sulphate, how many moles of precipitate will be formed?
Monday, November 21, 2016 by David

chemistry
Explain why sodium carbonate against hydrochloric acid titration using phenophthalein titration do not go to completion but stop at the sodium hydrogen carbonate stage.
Monday, November 21, 2016 by Bright

Chemistry
What is the morality of a solution prepared by dissolving 10.60g of sodium trioxocarbonate (v) in enough distilled water to obtain 250.0 ml of a solution?
Monday, November 21, 2016 by Charles

Chemistry
1.654 of a hydrated acid H2C2O4.xH2O was dissolved in water and the soultion was made up to 250cm3 . 23.80cm3 of this solution required 25.00cm3 of 0.100moldm-3 NaOH to reach the end point. Identify the value of x and the formula of the hydrated acid H2C2O4.xH2Or.
Monday, November 21, 2016 by Jemma

Chemistry
To what pH should you adjust a standard hydrogen electrode to get an electrode potential of -0.122 V ? (Assume that the partial pressure of hydrogen gas remains at 1 atm.)
Monday, November 21, 2016 by L

Chemistry
How much calories does it take to raise the temperature of 225 g of H2O from 25 °C to 100 °C. (Specific heat of water 4.182 J/(g* °C)
Monday, November 21, 2016 by Turtel

Chemistry
A patient requires 0.012 g of painkillers available as a 15 mg/ml solution. How many ml should be administered?
Monday, November 21, 2016 by Turtel

chemistry
What volume of alcohol would you use if you needed 25.0 g? Density is 0.7855 g/ml at 20°C
Monday, November 21, 2016 by Jayel

Chemistry
In an aqueous solution containing a mixture of Zn2+and Mg2+, how would you determine their contents by means of EDTA titration?
Monday, November 21, 2016 by Silvia

Chemistry
5g of salt are dissolved in 200g of water,what mass of solution is this?
Monday, November 21, 2016 by Pine

Chemistry
Write a balanced overall reaction from these unbalanced half-reactions. Sn->Sn2+ Ag+->Ag Balanced overall equation I got Sn+2Ag+->Sn+2Ag, but its wrong.
Sunday, November 20, 2016 by angie

chemistry
For the following reaction KClO2->KCl+O2 assign oxidation states to each element on each side of the equation. Reactants K=? Cl=? O=? Which element is reduced? I got K=5, Cl=-1, and O=-4 . The element that reduced is K, but its says its wrong. Help, Please!
Sunday, November 20, 2016 by chris12

Chemistry
A 24 L welding tank contains of 285 bar of argon at 28 °C. Nitrogen is added to obtain an 80:20 argon:nitrogen mixture. a) What are the partial pressures of argon and nitrogen? b) What will be the total tank pressure?
Sunday, November 20, 2016 by Po

chemistry
Suggest a source of error (not already mentioned) that would result in a value of x that is a) higher than the actual value b) lower than the actual value
Sunday, November 20, 2016 by Anonymous

Chemistry 20
A student was experimentally checking the stoichiometry of a reaction. The student correctly predicted that the reaction should produce 1.82 g of al2(so4)3(s). When the student dried and weighed the al2(so4)3(s) produced, its mass was 1.94 g. The percent difference of the ...
Sunday, November 20, 2016 by Tala

Chemistry 20
When 1.2 x 10^-3 mol of nitric acid react with excess sodium carbonate, how many moles of carbonic acid are produced?
Sunday, November 20, 2016 by Tala

Chemistry 20
If 4.56 mol of zinc react with excess copper (ii) sulphate, how many moles of precipitate will be formed?
Sunday, November 20, 2016 by Tala

Chemistry
To increase the acidity of soil, you can add peat, which contains a complex acid mixture known as humic acid. The complexity of the humic acid makes it difficult to determine how acidic you are making the soil. You decide to use a titration to get a better measure. If ...
Sunday, November 20, 2016 by Julia

Chemistry
What are the major species in a solution during the titration of citric acid with a strong base such as NaOH?
Sunday, November 20, 2016 by Lyn

statistics and probabilities
Suppose you will be taking exams in English, statistics and chemistry tomorrow and from past experience you know that for each exam you have a 50% chance of receiving an A. List all the possibilities for receiving A's on various exams. Letting X represents the number of A's ...
Saturday, November 19, 2016 by rhinechilde

Dr.Bob Chemistry
Is HOET associated with E1 or E2? I think it is E2.
Saturday, November 19, 2016 by Sarah

Chemistry
An electron in the n = 10 state of a hydrogen atom emits a photon with energy of 6.54×10–20 J. What is the final state of the electron
Saturday, November 19, 2016 by Jason

chemistry
Suppose f′′(x)=−36sin(6x) and f′(0)=−5, and f(0)=−3 f(π/3)=?
Friday, November 18, 2016 by angie

chemistry
Suppose f′′(x)=−36sin(6x) and f′(0)=−5, and f(0)=−3 f(π/3)=?
Friday, November 18, 2016 by angie

Chemistry
If you used 50 grams of copper (II) oxide, how much copper would be produced. (Use the ratio)
Friday, November 18, 2016 by Kelly

Chemistry
What can you conclude about the relative equilibrium concentrations of CrO4 ion in each of the solutions 0.1M K2Cr2O7 and 0.1M K2CrO4?
Friday, November 18, 2016 by Skyler

Organic chemistry
Nitrobenzene + KOH >>>>> ???
Friday, November 18, 2016 by Amal

chemistry
If dissolving 2g of ionic salt causes 50ml of water in increase temp. by 15 degrees Celsius at constant pressure, what would be the change in temperature if 6g of the same ionic salt were used instead? Assume the volume of solution remains the same.
Friday, November 18, 2016 by tommy

CHEMISTRY
CALCULATE THE OSMOLARITY OF THE FOLLOWING ).1M KNO3 & ).35M Na3PO4 & 0.35
Thursday, November 17, 2016 by BOBBI

AP Chemistry
Consider 54.0 mL of a solution of weak acid HA (Ka = 10^-6), which has a pH of 4.140. What volume of water must be added to make the pH = 5.000? [HA]=((10^-4.14)^2)/(10^-6) = 0.0052480746 0.0052480746 x 54 = c x v c= ((10^-5)^2)/(10^-6) = 10^-4 v= (0.0052480746 x 54)/(10^-4) ...
Thursday, November 17, 2016 by Efrem

Chemistry
A laboratory technician wants to determine the aspirin content of a headache pill by acid–base titration. Aspirin has a Ka of 3.0 × 10-4. The pill is dissolved in water to give a solution that is about 10-2 M and is then titrated with KOH solution. Find the pH at each of ...
Thursday, November 17, 2016 by J

Qualitative analysis ( Chemistry)
A solution x forms a white precipitate with dilute sulfur in acid and also with aqueous silver nitrate. What could solution x contain? A) Barium Chloride B) Barium nitrate C) Magnesium chloride D) Magnesium chlorine Could someone tell me how to get the answer and explain it to...
Thursday, November 17, 2016 by Cheezel

Chemistry
How many moles of hydrogen from when 10 moles of methane react completely?
Thursday, November 17, 2016 by Marissa

Chemistry
How many moles of water vapor react to yield 546.234 moles of hydrogen?
Thursday, November 17, 2016 by Marissa

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