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February 8, 2016

Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

Chemistry
How to find the mass of a solid formed when: 45.00ml solution of 0.003 800 mol/L lead (II) nitrate is mine dish a 30.00 mL solution of 0.08800 mol/L strontium iodide
Sunday, November 29, 2015 by Sam

chemistry Dr. BOB
A voltaic cell has one half-cell with a Cu bar in a 1.00 M Cu2+ salt and the other half-cell with a Cd bar in the same volume of a 1.00 M Cd2+ salt. Report your answers to the correct number of significant figures. a)Find E degree cell, delta G degree , and K. b)As the cell ...
Sunday, November 29, 2015 by Patrick

Chemistry
what mass of barium carbonate will dissolve in a 2.50L solutions of 0.0500 molar sodium carbonate
Sunday, November 29, 2015 by Sam

Chemistry
Determine the number of moles of N2 that are required to produce 12 mol of NH3 using the equation, N2 + 3H2 --> 2NH3. 12 mol NH3 x 1 mol N2/2 mol NH3 = 6 moles of N2.
Sunday, November 29, 2015 by Beth

Chemistry Dr Bob
A voltaic cell has one half-cell with a Cu bar in a 1.00 M Cu2+ salt and the other half-cell with a Cd bar in the same volume of a 1.00 M Cd2+ salt. Report your answers to the correct number of significant figures. a)Find E degree cell, delta G degree , and K. b)As the cell ...
Sunday, November 29, 2015 by Patrick

Chemistry
Which solution will have the lowest pH? a. 0.10 M HClO2, pKa = 1.96 b. 0.10 M HCN, pKa = 9.21 c. 0.10 M HF, pKa = 3.19 d. 0.10 M HClO, pKa = 7.538 e. 0.00010 M HCl Does the lower the pka stronger the acid, means the lower the ph, so the answer is A?
Sunday, November 29, 2015 by Anonymous

Chemistry
If you want to prepare 2.0 liters of a .25 M solution of NH4Cl, how many grams of the salt should you weigh out?
Sunday, November 29, 2015 by J

Chemistry
Sulfuric acid is produced commercially by the reactions indicated below at the appropriate percent yields for each step. The second step utilizes air as a source of oxygen and heats it to 4000C in the presence of vanadium (V) oxide, a catalyst. Assuming air is 21% oxygen by ...
Sunday, November 29, 2015 by Adam

Chemistry
If 5.026g chromium is combined with 3.04L of chlorine gas at 0.955atm and 220C, what mass of chromium (III) chloride is produced?
Sunday, November 29, 2015 by Adam

Chemistry Dr BOB
A voltaic cell has one half-cell with a Cu bar in a 1.00 M Cu2+ salt and the other half-cell with a Cd bar in the same volume of a 1.00 M Cd2+ salt. Report your answers to the correct number of significant figures. a)Find E degree cell, delta G degree , and K. b)As the cell ...
Sunday, November 29, 2015 by Patrick

chemistry
In the preparation of ammonia, why should the mixture of ammonium chloride and calcium hydroxide be a paste, not dry powder?
Sunday, November 29, 2015 by clive

Chemistry
The population ratio between two energy levels separated by 1.4 ✕ 10−22 J is 0.69. What is the temperature of the system?
Sunday, November 29, 2015 by Anonymous

Chemistry- Dr.Bob
Why is cis-PCl3F2 polar and trans-PCl3F2 nonpolar?
Saturday, November 28, 2015 by Sanaya

Math
In chemistry class, each of the 82 students needs 72 mL of base. How many one- liter bottles of base need to be available? Help?
Saturday, November 28, 2015 by kristine

CHEMISTRY URGENT HELP
How to draw line graph for showing changes in test tubes while showing that exhaled air contains more carbon dioxide than inhaled air
Saturday, November 28, 2015 by mark

chemistry
You want to prepare 500 ml of 1.0M acetic acid from a 17.4 M stock solution.What volume of stock solution is required?
Saturday, November 28, 2015 by omar

Chemistry
The intreval volume of a clorimeter was1.12L. A sample of gas of 1.863g of nonae was added, and the closed calorimeter then had added oxygen until the pressure was 10.0atm na dht etemp was 23.1 C.Write the full balanced equation of the combustion of the nonae in the ...
Saturday, November 28, 2015 by sarah

Chemistry
If 34.3 mL of barium hydroxide are required to neutralize 15.9 mL of the acid, what is the molarity of the hydrochloric acid solution?
Saturday, November 28, 2015 by Kaitlin

chemistry DR BOB
A voltaic cell has one half-cell with a Cu bar in a 1.00 M Cu2+ salt and the other half-cell with a Cd bar in the same volume of a 1.00 M Cd2+ salt. Report your answers to the correct number of significant figures. a)Find E degree cell, delta G degree , and K. b)As the cell ...
Saturday, November 28, 2015 by Patrick

Chemistry
The population ratio between two energy levels separated by 1.4 ✕ 10−22 J is 0.69. What is the temperature of the system?
Saturday, November 28, 2015 by Anonymous

Chemistry
Find the volume of 0.250M sulfuric acid necessary to react completely with 79.3g sodium hydroxide
Saturday, November 28, 2015 by Tiffany

chemistry
When a 10 g sample of copper oxide is reduced by heating in the presence of carbon monoxide, how many moles of copper are formed?
Saturday, November 28, 2015 by sara

physical chemistry
calculate the mass of NaCl needed to prepare 1000cm of 0.025M solution (molar mass of NaCl is 58.5)
Saturday, November 28, 2015 by Anonymous

chemistry
500 calories are added to 100 gram copper at 25 degree celsius a.what will be the final temperature? b.if the same amount of heat was added to an equal amount of water,what would be the final temperature?
Friday, November 27, 2015 by jhanz

Chemistry
For a Sc atom in ground electronic state: 1. how many electrons are there in 4s orbitals? 2. how many electrons are there in 3d orbitals? 3. how many electrons are there in 4p orbitals? 4. how many unpaired electrons are there? 5. to what block does Sc belong to in the ...
Friday, November 27, 2015 by S

Chemistry
The population ratio between two energy levels separated by 1.4 ✕ 10−22 J is 0.69. What is the temperature of the system?
Friday, November 27, 2015 by Anonymous

Chemistry
Consider the 5p orbital of a hydrogen atom. 1. how many different 5p orbitals are there? 2. how many radial nodes are there? 3. how many angular nodes are there? (i.e. how many nodal planes or surfaces, not including radial nodes)
Friday, November 27, 2015 by S

Chemistry
A toothpaste contains 0.220 % by mass sodium fluoride used to prevent dental caries and 0.32 % by mass triclosan C12H7Cl3O2, an antigingivitis agent. One tube contains 119 g of toothpaste. How many fluoride ions, F−, are in the tube of toothpaste? How many grams of ...
Friday, November 27, 2015 by xyz

Chemistry
In photosynthesis, glucose, C6H12O6, and O2 are produced from CO2 and H2O. Glucose from starches is the major fuel for the body. 6CO2(g)+6H2O(l)+680kcal⟶ C6H12O6(aq)+6O2(g) How much heat, in kilojoules, is needed to produce 22.5 g of C6H12O6?
Friday, November 27, 2015 by veen

Chemistry
When CH3OH at its normal boiling point, does its entropy increase or decrease? Explain. - My opinion The entropy decreases because there is less order due to the less randomness of gas particles favoured when such an element is boiled not at normal boiling point?
Friday, November 27, 2015 by Liam

Chemistry
calculate the molar solubility of BaCO3 in a 0.10M solution of NaCo3 (aq). (ksp(BaCO3)=8.1x10^-9)
Friday, November 27, 2015 by Kia

Chemistry
A 0.200 g sample of carbon dioxide, CO2, has a volume of 525 mL and a pressure of 473 mmHg . What is the temperature of the gas in kelvins?
Friday, November 27, 2015 by joey

Chemistry
How many joules are needed to change 163.34 g of water at 54.1 °C to steam at 100 °C?
Friday, November 27, 2015 by Miles

Chemistry
What would the volume be of 0.955g of propane at 735 torr and 35.00C? And How many mols of xenon would be required to create a mixture with a mole fraction of xenon of 0.0190 if the mixture were also to contain 2.16mol argon and 3.612g neon? Thanks in adavance
Friday, November 27, 2015 by Adam

Chemistry
Water is a liquid at STP. Hydrogen sulfide, H2S, a heavier molecule, is a gas under the same conditions.Explain, using diagrams, why this is so.
Friday, November 27, 2015 by Neishia

Chemistry
A concentrated H2SO4 solution is 10.5 M. You have to make 255 mL of 0.650 M solution. How would you prepare it?
Friday, November 27, 2015 by Neishia

Chemistry
Benadryl is an over-the-counter drug used to treat allergy symptoms. The formula of benadryl is C17H21NO. How many moles of C are present in 0.759 mole of benadryl?
Friday, November 27, 2015 by tom

Chemistry
what volume of oxygen at 423.0K and a pressure of 127.4kPa will be produced by the decomposition of 129.7g barium peroxide to form barium oxide and oxygen gas? Thank you
Friday, November 27, 2015 by Adam

Chemistry
how you would prepare 250 mL of 0.25 M NaOH from solid NaOH and water?
Friday, November 27, 2015 by Neishia

Organic Chemistry
What is the optical purity of a partially racemized product is the calculated specific rotation is -8◦ and the pure enantiomer has a specific rotation of -10◦? Calculate the percentage of each of the enantiomers in the partially racemized product. I'm very lost...
Friday, November 27, 2015 by nicole

Chemistry
The theoretical yield of a reaction is the amount of product obtained if the limiting reactant is completely converted to product. Consider the reaction: P4(s) + 6 Cl2(g) → 4 PCl3(l) If 19.47 g P4 is mixed with 6.85 g Cl2, calculate the theoretical yield (g) of PCl3 ...
Thursday, November 26, 2015 by Riley

Chemistry
A Sample of propane, C3H8, occupies 5.00L at 270C and 309torr. The volume of the canister is changed to 1.85L while the pressure remains constant. What is the Temperature, in K and 0C, of the gas after the change? What would be the setup for this problem? Thank you.
Thursday, November 26, 2015 by Adam

Chemistry
A sample of oxygen occupies 38.9L at STP. What will the pressure need to be in Torr. if the volume is to be changed to 32.2L without a change in T. Is this P1V1/T2=P2V2/T2? How would I set it up.
Thursday, November 26, 2015 by Johnny

Chemistry
Assume you have prepared 100.0 mL of a buffer solution using 0.400 mol of acetic acid (pKa = 4.74) and 0.400 mol of sodium acetate. The pH of this buffer solution is initially 4.74. After preparing this buffer solution, you added 55.0 mL of a 1.10 M NaOH solution to your ...
Thursday, November 26, 2015 by J

Chemistry
A chemist needs to prepare a buffer using the carbonate system (information in the table in the previous quetion) with a final pH of 10. Which components should they mix in water to product this buffer? Question options: H2CO3 HCO3- CO32-
Thursday, November 26, 2015 by J

Chemistry
A chemist needs to prepare a buffer using the carbonate system (information in the table below) with a final pH of 6. Which components should they mix in water to product this buffer? H2CO3 HCO3- CO32- pKa 6.35 10.33 N/A
Thursday, November 26, 2015 by J

Chemistry
The pH of a buffer can be predicted using the Hendersen-Hasselbach equation: pH=pKa+ log([conjugate base][conjugate acid]) The choice of the conjugate acid-base pair (as you did in the previous questions) determines the pKa value to be used in the H-H equation. By varying the ...
Thursday, November 26, 2015 by J

Chemistry
6.2g of NaOH is added to 800ml of water What is the molarity of the solution? What is the pH?
Thursday, November 26, 2015 by Tegan

Chemistry
The equilibrium constant for Br2 + Br <-> Br3 at 25 degrees is 18. Calculate the equilibrium constant Br3 <-> Br2 + Br
Thursday, November 26, 2015 by Lori

Chemistry - Energy Phase Changes
Calculate the quantity of heat gained or lost in the following change: 0.44 mol of water evaporates at 100 degrees Celsius - So what I did was: 1 mol -> 6.01 kJ 0.44 mol -> x x = 2.64 kJ of energy gained But apparently this is incorrect? Could somebody please explain to ...
Wednesday, November 25, 2015 by Kid

chemistry
How many grams of bismuth (III) chloride can be produced from 575 mL of chlorine gas at STP when reacting with excess bismuth metal?
Wednesday, November 25, 2015 by nicholas

Chemistry
Automotive airbags inflate when sodium azide, NaN3, rapidly decomposes to its constituent elements according to the chemical equation, 2 NaN3 -> 2 Na + 3 N2. How many grams of nitrogen are produced when 1000 milligrams of sodium azide decomposes?
Wednesday, November 25, 2015 by Sarah

chemistry
how many molecules are present in a 750 ml of C6H12O6
Wednesday, November 25, 2015 by Anonymous

Chemistry
Write the formulas of the compounds formed by NH4+ with the following anions: CN-, ClO3-, SO42-, H2PO4-
Wednesday, November 25, 2015 by Kim

Chemistry
A sample of air was passed through an electrical discharge causing the following reaction N2(g) + O2(g)->2NO(g) . Assuming that 1.00 mole of air (78% N2, 21% O2) was originally present at 1.00 atm, determine the partial pressure (in atm) of NO at equilibrium. Kp = 0.0123 at...
Wednesday, November 25, 2015 by Anonymous

chemistry
explain how you would obtain solid lead carbonate from a mixture of lead carbonate and sodium carbonate powder
Wednesday, November 25, 2015 by diane

Chemistry
1.)An ammonia/ammonium buffer solution contains 0.35 M NH3 and 0.72 M NH4+. The Kb value of ammonia is 1.8×10−5. Calculate the pH of this buffer. 2.) Nitrous acid has a Ka of 4.5×10−4. What is the pH of a buffer solution containing 0.15 M HNO2 and 0.20 ...
Wednesday, November 25, 2015 by LuigiR

Chemistry
How many miles of oxygen would it take to react with 1.0 moles of magnesium
Tuesday, November 24, 2015 by Abby

Chemistry
A student adds 3.50 g of dry ice (solidCO2 ) to an empty balloon. What will be the volume of the balloon at STP after all the dry ice sublimes (converts to gaseousCO2 )?
Tuesday, November 24, 2015 by Diamond

Chemistry
When a 10 g sample of copper oxide is reduced by heating in the presence of carbon monoxide, how many moles of copper are formed?
Tuesday, November 24, 2015 by Leo

international university of east africa.chemistry
20cm of sulphuric acid required 18.5cm of 0.1M sodium hydroxide solution for complete neutralisation.
Tuesday, November 24, 2015 by cosmas

Chemistry
What will happen if 100g of NaCl is placed in 200mL of water at 70C
Tuesday, November 24, 2015 by Navi

Chemistry
you have 5% formic acid solution and a 5% acetic acid solution. You titrate 5mL each with .1868M NaOH. A. Which will need more NaOH to reach the end point? B. How much more?
Tuesday, November 24, 2015 by jack

Chemistry
1. In the lab you will be provided with 0.1 M sodium hydroxide that you will standardize using KHP. What is implied by writing the NaOH concentration as 0.1 M? a) After performing your standardization and calculations, any deviation from 0.1000 M is due to experimental error. ...
Tuesday, November 24, 2015 by Dan

Chemistry
Why is Hydrogen sulfate amphiprotic?
Monday, November 23, 2015 by John

chemistry
The UNBALANCED equation is: Zn + HCl –] ZnCl2 + H2 How many milliliters of a 0.48 M HCl solution are needed to react completely with 7.4 g of zinc to form zinc(II) chloride? Answer in units of mL. 7.4/100.84g*2 mol
Monday, November 23, 2015 by Kiley

chemistry
If we have a mixture of 0.33 moles of oxygen and 0.22 moles of carbon dioxide, the mole fraction of carbon dioxide is .
Monday, November 23, 2015 by Anonymous

Chemistry
A sample of 5.61 grams of NaOH is dissolved into 627 mL of aqueous 0.250 M NaOH (assume no volume change). This solution is then poured into 2.16 gallons of water. (You may assume that the two volumes can be added.) What is the concentration of NaOH in the final solution? ...
Monday, November 23, 2015 by Anonymous

Chemistry
In the electrolysis of water 75.0 cm3 of oxygen gas are produced.How many cm3 of hydrogen are produced ?
Monday, November 23, 2015 by Nick

Chemistry
How commonly is salicylic acid used or found in nature ?
Monday, November 23, 2015 by Jake

Chemistry
patient on dialysis has a high level of urea, a high level of sodium and a low level of potassium in the blood. Why is the dialyzing solution prepared with a high level of potassium but no sodium or urea?
Monday, November 23, 2015 by ayyei

Chemistry
What is the Lewis structure for salicylic acid ?
Monday, November 23, 2015 by Jake

Chemistry
Calculate The volume occupied at s.t.p by 0.24g of ozone ( o=16, G.M.V=22.4dm3
Monday, November 23, 2015 by moses

chemistry
Write the structural formula of differnt isomers gives by the molecular formula CrCl3 6H2O.
Monday, November 23, 2015 by md rafiqul sk

chemistry
Determine if the following reaction is spontaneous under standard conditions. Zn(s) + 4 CN¡V(aq) + Ag2CrO4(s) „³ Zn(CN)42¡V(aq) + 2 Ag(s) + CrO42¡V(aq)
Monday, November 23, 2015 by cole

Chemistry
A gas weighing 23.6 g occupies a 10.0 L flask at 27 C and 780. torr of pressure. Calculate the molar mass of the gas.
Monday, November 23, 2015 by Ron

chemistry
Sketch the phase diagram of argon, Ar, from the following information: Normal melting point = –187°C Normal boiling point = ‒186°C Triple point = ‒189°C, 0.68 atm Critical point = ‒122°C, 48 atm Label the triple point, critical point and ...
Sunday, November 22, 2015 by elan

Chemistry
The reaction 2H2S(g)⇌2H2(g)+S2(g) Kc=1.67×10−7 at 800∘C is carried out with the following initial concentrations: [H2S] = 0.300 M , [H2] =0.300 M , and [S2] = 0.00 M. Find the equilibrium concentration of [S2].
Sunday, November 22, 2015 by hoooo

Chemistry
1. Which molecule should have the higher dipole moment, and why? a) COF2 because it contains more F atoms. b) COFH because the polar bonds in COF2 nearly cancel each other out. c)COF2 because it contains more lone pairs. >> I think the answer is a)?
Sunday, November 22, 2015 by Dan

Chemistry
For which element is the gaining of an electron most exothermic? a)Li b)N c)F d)B *explain
Sunday, November 22, 2015 by Mark

Chemistry
Anthracene is a yellow, crystalline solid found in coal tar. Complete this structure for anthracene, C14H10, by adding bonds and hydrogen atoms as necessary. What type of hybrid orbitals are utilized by carbon in anthracene? >>sp3 How many σ bonds and π bonds ...
Sunday, November 22, 2015 by Dan

Chemistry
Why does carbonate have a -2 charge and not -1? Why does phosphate have a -3 charge and not -2 or -1? Why does nitrate have a -1 charge and not -2 or -3? My answer: Based on the Lewis structure, these ions need a certain number of electrons in order to be stable...the octet ...
Sunday, November 22, 2015 by Christina

Chemistry
Rank the following in order of increasing bond polarity: H-F, H-Br, F-F, Na-Cl. Is it this....? F-F, H-Br, H-F, Na-Cl
Sunday, November 22, 2015 by Christina

chemistry
a 10.0 ml sample of a hcl solution is titrated with 32.6 ml of a 0.155 m naoh solution. what is the equation for the neutralization reaction?
Sunday, November 22, 2015 by lakeisha

Chemistry
Why does carbonate have a -2 charge and not -1? Why does phosphate have a -3 charge and not -2 or -1? Why does nitrate have a -1 charge and not -2 or -3? My answer: Based on the Lewis structure, these ions need a certain number of electrons in order to be stable...the octet ...
Sunday, November 22, 2015 by Christina

Chemistry
What is the pressure of 1.78 g of nitrogen gas confined to a volume of .118 L and 25 degrees Celsius?
Sunday, November 22, 2015 by Lyndsay

University
Chemistry The molar heat capacity of butane under constant pressure Cp=19.4 + 0.233 T J.mol' '.K' . Calculate the quantity of heat needed to increase the temperature from 27"C to 127 ° Cu under1 atm pressure.
Sunday, November 22, 2015 by Zahra

Chemistry
Calculate the molar concentration for each of the following. a)The concentration of a brine solution containing 225 g for pure sodium chloride dissolved in 4.00 L of solution. b)The volume that must be added to 4.2 mol of magnesium chloride to make a 0.045 M solution. c)The ...
Sunday, November 22, 2015 by Lyn

Chemistry
The overall cell reaction occurring in an alkaline battery is: Zn(s) + MnO2(s) + H2O(l) ---> ZnO(s) + Mn(OH)2(s) a) How many moles of electrons flow per mole of reaction?...answer: 2. Mol e-Note: b) If 6.09g of zinc is oxidized, how many grams of manganese dioxide and of ...
Saturday, November 21, 2015 by Dalton

chemistry
I have two that I can not figure out: #1: calculate the MOLALITY of 10.00 g/L of the salt, if its molar mass is 100.0 g/mol and solution density D=1.100 g/mL work: 10.00 g NaCl x (1mL/1.100g) x (1kg/1000 mL)= 0.00909 kg 100.0 g x (1 mol NaCl/58.4 g Nacl)= 1.7 mol 1.7/0.0090= ...
Saturday, November 21, 2015 by sam

Chemistry
7) A 3.33 g sample of iron ore is transformed into a solution of iron (II) sulfate. And this solution is titrated with 0.0150 M potassium dichromate. If it requires 41.40 mL potassium dichromate solution to titrate the FeSO4, find the percentage of iron in the ore? The mole ...
Saturday, November 21, 2015 by CHIPNDALE

Chemistry
7. Suppose 45.0 mL of 0.250 M HNO3 was mixed with 35.0 mL 0.600 M Ba(OH)2. Calculate the pH of the final solution.
Saturday, November 21, 2015 by CHIPNDALE

Chemistry
If 5.00L of argon gas is at 0.460 atm and -123C what is the volume at STP I think it's b
Saturday, November 21, 2015 by Miguel

Chemistry
Methyl alcohol can be prepared commercially by the reaction of hydrogen with carbon monoxide. Under equilibrium conditions at 7.00 × 102 K, [H2] = 0.0720 M, [CO] = 0.200 M, and [methanol] = 0.0300 M. Find the value of Kc, and then find the value of Kp. What is the value ...
Saturday, November 21, 2015 by Anonymous

Chemistry
What is the total number of joules of hear needed to change 200g of ice to water at O degree Celcius?
Saturday, November 21, 2015 by Andrea

Chemistry
What is the chemical formula for coconut oil?
Saturday, November 21, 2015 by Alicia

Chemistry
predict if precipitation will occur when 36ml of 0.0039M Na2CrO4 is mixed with 18ml of 0.00033M AgNO3. M.W of Ag2CrO4 :331.73g/mol Kspof ag2cro4 1.1x10^-12
Saturday, November 21, 2015 by Janna

Chemistry
An aqueous solution of KF is add dropwise to an aqueous micture containing 0.25M Ca2+ and 0.75M Mg2+ calcuate the minimum molarity of F that is nessaryvto initate the precipitation of each salt? Which precipitate first? Ksp of CaF2 :5.4x10^-9 Ksp of MgF2 :3.6x10^-8
Saturday, November 21, 2015 by Tom

chemistry
3.5g
Saturday, November 21, 2015 by feoluwa

chemistry
how many grams of CaCO3 will dissovle in 300ml of 0.05M Ca(NO3)2 ? Ksp of CaCO3 : 4.7x10^-9 M.W of CaCO3 100.01g/mol
Saturday, November 21, 2015 by Rose

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Homework Help: Science