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July 31, 2015

Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

Analytical Chemistry
A 22.617 g sample of aqueous waste leaving a fertilizer manufacturer contains ammonia. The sample is diluted with 70.407 g of water. A 10.883 g aliquot of this solution is then titrated with 0.1072 M HCl. It required 29.32 mL of the HCl solution to reach the methyl red ...
Thursday, February 28, 2013 by Sam

chemistry
2.06 X 10^25 formula units of aluminum sulfate would have what mass?
Thursday, February 28, 2013 by Anthony

chemistry
1040 grams of chlorine gas at STP would have what volume?
Thursday, February 28, 2013 by Anthony

chemistry
If you are given 718 grams of lead (iv) oxalate, how many atoms of oxygen do you have?
Thursday, February 28, 2013 by Anthony

Chemistry
Calculate the mass of HONH2 required to dissolve in enough water to make 255.5 mL of solution having a pH of 10.02 (Kb = 1.110−8).
Thursday, February 28, 2013 by Margaret

Chemistry
What is the mass of the carbon atoms in one mole of c3h8
Thursday, February 28, 2013 by Anonymous

Chemistry
The standardized NaOH solution was determined to be 120M whereas the mass of the sample of impure tartaric acid was 1.35g. If the initial reading of the buret volume changed from 48 ml to a final reading of 17 ml at the endpoint of the titration of the impure sample calculate ...
Thursday, February 28, 2013 by Jonah

Chemistry
calculate the amount of energy required to vaporize 43.0g of water at its boiling point
Thursday, February 28, 2013 by Richie

chemistry
What is the volume occupied by 20.2g NH3(g) at -25 degrees celsius and 752 mmHg? This is Ideal Gas Law.
Thursday, February 28, 2013 by Ambrosia

chemistry
Which of the following statements is /are true? Answer a. None of he above. b. Impurities in a solvent raise the freezing point of that solvent c. All of the above d. Non-volatile impurities lower the boiling point of a solvent e. Ions lower the vapor pressure of a solvent ...
Thursday, February 28, 2013 by alia

Chemistry
Pantothenic acid id one of the B vitamins. A sample of pantothenic acid was found to produce 3.84 mL of nitrogen gas, N2 at 23 degrees celsius and 785 mmHg. What is the volume of the nitrogen gas (in liters) produced as 29 degrees celsius and 0.993 atm?
Thursday, February 28, 2013 by Kirstyn

Chemistry
30cm of 0.3molar solution (0.3mol) were diluted to 0.1molar solution(0.1mol) by addition of water calculate A. The new molar solution B. Volume of water added
Thursday, February 28, 2013 by Turuchukwu

Chemistry
An electrolytic tin-coating process gives the coating 30 millionths of an inch thick. How many square meters can be coated with one kilogram, density 7.30 g/cm^3?
Thursday, February 28, 2013 by Alison

general chemistry
When divers exhale beneath the surface of the water, bubbles rise to the surface. Explain this behavior.
Wednesday, February 27, 2013 by Donna

ap chemistry
Given the following information, which of the following shows the acids in order from strongest to weakest? The order of atomic radii is I > Br > Cl, the order of bond strengths is HOI > HOBr > HOCl, and the order of electronegativities is Cl > Br > I.
Wednesday, February 27, 2013 by cheri

general chemistry College
Which of the following mixture would be most likely to produce carbon dioxide? Explain Why? a. magnesium and nitric acid: Mg+ HNO3 b. sodium carbonate and sufuricacid: Na2CO3+H2SO4 c. H2O+ Cu
Wednesday, February 27, 2013 by Donna

general chemistry College
Which of the following mixture would be most likely to produce carbon dioxide? Explain Why? a. magnesium and nitric acid: Mg+ HNO3 b. sodium carbonate and sufuricacid: Na2CO3+H2SO4 c. H2O+ Cu
Wednesday, February 27, 2013 by Donn

chemistry
How many liters of 2.09 HCl solution would be needed to prepare 1.14 L of 0.69 M HCl solution?
Wednesday, February 27, 2013 by Isaiah

ap chemistry
Arrange the bases I) deuterated ammonia (ND3) Kb = 1.1 × 10−5; II) hydrazine (NH2NH2) Kb = 1.7 × 10−6; III) hydroxylamine (NH2OH) Kb = 1.1 × 10−8; IV) ammonia (NH3) Kb = 1.8 × 10−5; in decreasing order of strengths.
Wednesday, February 27, 2013 by cheri

Chemistry calorimeter.. please help!
A coffee cup calorimeter contains 100ml of .200M H2SO4 at 22.3 degrees Celsius. When 2.16g Mg is added, the temperature rises to 36.3 degrees Celsius. What is the heat of the reaction per mole Mg? Please help and show steps. Much appreciated :)
Wednesday, February 27, 2013 by samantha

Chemistry
How much 5M KOH must be added to 1.0 L of 0.1M glycine (pKa 9.6) at pH 9.0 to bring its pH to exactly 10.0?
Wednesday, February 27, 2013 by Cristian

Chemistry
Calculate the mass of baking soda, NaHCO3, needed to neutralize 3.0 mL of 3.0 M hydrochloric acid, HCl(aq). Ok, so I'm super confused. I have the equation, but I'm stuck with what to do with it. Equation: NaHCO3 + HCL --> NaCl + H2O + CO2
Wednesday, February 27, 2013 by Sarah

chemistry
determine h30+ in M, of 10.00ml of .100M NaOH after adding 10.00ml of indicator solution?
Wednesday, February 27, 2013 by tina

Chemistry
Consider the reaction 3Fe(s) + 4H2O(g) ¨ 4H2(g) + Fe3O4(s). If the volume of the container is reduced, 1. more Fe(s) is produced. 2. no change occurs. 3. more H2O(g) is produced. 4. more H2(g) is produced. 5. the equilibrium constant increases.
Wednesday, February 27, 2013 by Ashley

chemistry dilution
Given VLP with concentration 200ug/mL, dilute to 3ug/100ul. Please help me with this; many thanks
Wednesday, February 27, 2013 by Reese

Chemistry
At 627ºC, sulfur dioxide and oxygen gases combine to form sulfur trioxide gas. At equilibrium, the concentrations for sulfur dioxide, oxygen, and sulfur trioxide gases are .0060M, .0054M, and .0032M, respectively. a. Write a balanced equation for the formation of ...
Wednesday, February 27, 2013 by dauntedorange

Chemistry
Considering the following precip reaction Pb(NO3)2(aq)+2KI(aq)----->PbI2(s)+2KN​O3(aq) What is the correct net ionic equation? I think it is 2NO3+^-+2K^+---->2KNO3
Wednesday, February 27, 2013 by STAT

chemistry
If a student attempts to identify an unknown compound by methodused in this experiment. She finds that when she heated a sampleweighing 0.4862 g the mass went down appreciably, to 0.3067 g. Whenthe product was converted to chloride, the mass went up, to 0.3382g. a. Is the ...
Wednesday, February 27, 2013 by johnson

chemistry
what is the temperature (degree celcius) of 1.75g of o2 gas occupying 4.6l at 1.00 atm?
Wednesday, February 27, 2013 by Anonymous

Chemistry
Calculate the mass of HONH2 required to dissolve in enough water to make 255.5 mL of solution having a pH of 10.02 (Kb = 1.110−8).
Wednesday, February 27, 2013 by Margaret

Chemistry
The vapor pressure of pure acetone (propanone) is 266 torr. When a non-volatile solute is added, the vapor pressure of acetone above the solution falls to 232 torr. What is the mole fraction of acetone in the solution? Show work. A) 0.69 B) 0.32 C) 0.13 D) 0.045 E) 0.87
Wednesday, February 27, 2013 by Dee

Chemistry
Isoamyl salicylate (м = 208.25 g/mol) has a pleasant aroma and is used in perfumes and soaps. Which of the following combinations gives a 0.75 m solution of isoamyl salicylate in ethyl alcohol (d = 0.7893 g/mL)
Wednesday, February 27, 2013 by Dee

chemistry
When the concentration of CH3Br and NaOH are both 0.150M, the rate of the reaction is 0.0020M/S. (a) What is the rate of the reaction if the concetration of CH3Br is doubled? _______________M/s (b) What is the rate of the reaction if the concentration of NaOH is halved? ...
Wednesday, February 27, 2013 by dj

chemistry
A sample of oxygen that occupies 1.00x10^6 mL at 575 mm Hg is subjected to a pressure of 1.36 atm. What will the final volume of the sample be if the temperature is held constant?
Wednesday, February 27, 2013 by peyton

chemistry
How many grams of O2 are needed to produce 45.8 grams of Fe2O3 in the following reaction? 4Fe(s)+3O2(g) - 2Fe2O3(s)
Wednesday, February 27, 2013 by richard w

chemistry
How many grams of ammonium fluoride are required to neutralize 972 'm of 0.00327 M sulfuric acid
Wednesday, February 27, 2013 by caleb

Analytical Chemistry
Calculate the pH at the equivalence point for the titration of 0.160 M methylamine (CH3NH2) with 0.160 M HCl. The Kb of methylamine is 5.0× 10–4. Methylamine is a weak base and reacts with HCl to give the methylammonium ion. HCl + CH3NH2 <---> CH3NH3^+ + Cl^- ...
Wednesday, February 27, 2013 by Sam

chemistry
A catalytic converter combines 2.55 g CO with excess O2. What mass of CO2 forms?
Wednesday, February 27, 2013 by megan

Chem
hydrate mean in an inorganic chemistry context
Wednesday, February 27, 2013 by Anonymous

CHEMISTRY
Hydrogen cyanide is used in the production of cyanimid fertilisers. It is produced by the following reaction: 2CH4 + 2NH3 + 3O2  2HCN + 6H2O (a) How much hydrogen cyanide can be produced starting with 100 kg of each of the reactants? (b) Which is the limiting reagent?
Wednesday, February 27, 2013 by alex

Chemistry
This is a back titration question and I'm struggling with it :/ So if you can help me, that would be very appreciated :) Q. A sample of steel wool was dissolved in excess sulfuric acid. The resulting solution (FeSO4 aq) was then titrated with potassium permanganate. 26.5mL...
Wednesday, February 27, 2013 by Rapunzel

Chemistry
Mg + HCl ----> MgCl2 + H2 If the water in tube is evaporated , the other product , a white salt remains . Write the balanced chemical equation . Ans: Mg + HCl ----> MgCl2 + H2 + H2O I don't know how to balanced it . I'm confusing where O is in reactants to ...
Wednesday, February 27, 2013 by Maria

Chemistry Lab
Hi, I'm doing a lab with acid-base indicators and I'm utterly confused. The lab procedure goes like this: 1) Make your own indicator. 2) set up 12 test tubes and pout a little pH solution into tube. 3) add 4 drops of indicator into each test tube. 4) Estimate the ...
Wednesday, February 27, 2013 by ConfusedStudent

chemistry
What is the structure of H2P2O6??
Wednesday, February 27, 2013 by nitesh

chemistry
what mass of ammonium chloride is dissolved in 100 grams water in each of the following solutions in 1.10 molal NH4Cl solution, in a solution which is 75% water by mass in solution with a mole fraction of 0.15 NH4Cl? please help me solve this problem. thank you!
Wednesday, February 27, 2013 by andrea

chemistry
What's the percentage of the H202 that has been consumed if you use 11.5ml of water, 3.0ml buffer, 2.5ml KI, 1.0ml starch, 1.0ml Na2S203.and 1.0ml H202
Wednesday, February 27, 2013 by StressedStudent

chemistry
I am having trouble on this please help Indicate which of these statements is true? For those that are false,.explain why a) addition reactions always involve compounds with multiple bonds b) all addition reactions produce polymers, but not all polymers are addition polymers c...
Wednesday, February 27, 2013 by K

chemistry
Express your answers as integers separated by commas.
Tuesday, February 26, 2013 by Anonymous

Chemistry
What volume of 1.60 M SrCL2 is needed to prepare 525 ml of 5.00mM SrCl2?
Tuesday, February 26, 2013 by Candace

college chemistry
during a liquid-liquid extraction the procedure often calls for the use of saturated NaCl when ether is used as the extraction solvent, but not when dichloromethane is used. why?
Tuesday, February 26, 2013 by Anonymous

chemistry
I need to find the radius of a cylinder with only the following info: Cylinder height=125um There is 1 C atom/0.01848 nm^2 There are 5.75x10^10 C atoms on the surface of cylinder Use quadratic formula to solve
Tuesday, February 26, 2013 by kelly

chemistry
How much heat in joules is required to heat a 44g sample of aluminum from 76 F to 148 F?
Tuesday, February 26, 2013 by tish

Chemistry
calculate the energy in joules lost when 70.0 grams of water cools from 86.4 celsius to 7.1 celsius
Tuesday, February 26, 2013 by anon

Chemistry
In a constant-pressure calorimeter, 60.0 mL of 0.320 M Ba(OH)2 was added to 60.0 mL of 0.640 M HCl. The reaction caused the temperature of the solution to rise from 23.24 °C to 27.60 °C. If the solution has the same density and specific heat as water, what is ÄH ...
Tuesday, February 26, 2013 by Blaire

chemistry
Commodity prices of NaCl and urea are about $0.033/lb for NaCl (as rock salt) and about $0.10/lb for urea. Calculate the cost of treating 1000 lb of ice on a surface to produce a solution that melts at -3.9 degrees Celsius with each chemical. I know you use to delta T= mkfi ...
Tuesday, February 26, 2013 by K

Chemistry
2Al(s)+3Cl2 = 2AlCl3 Limiting Reactant is Cl with 0.329mol. What is the maximum mass of aluminum chloride that can be formed when reacting 30.0g of aluminum with 35.0g of chlorine?
Tuesday, February 26, 2013 by Veronica

Chemistry
What is the maximum mass of aluminum chloride that can be formed when reacting 30.0g of aluminum with 35.0g of chlorine
Tuesday, February 26, 2013 by Veronica

Chemistry
I have o.236 g for urea and 0.235g for NaCl. And the question is On a gram basis, which is more effective in depressing the freezing point, urea or NaCl? On a mole basis, which Is more effective? I am confused on what depressing the freezing point me and idk how to explain the...
Tuesday, February 26, 2013 by K

Chemistry
what is the empirical formula for a compund with 26.2 g N, 7.5 g H, and 66.3 g Cl?
Tuesday, February 26, 2013 by Anonymous

chemistry
identify the reducing and the oxidizing agent for each reaction: a) 2na + br2 = 2nabr b) h2 + cl2 = 2hcl c) 2li + f2 = 2lif d) s + cl2 = scl2 e) n2 + 2o2 = 2no2 f) mg + cu(no3)2 = mg(no3)2 + cu
Tuesday, February 26, 2013 by mfsl123

Chemistry
Consider the titration of 25.0mL of 0.10M HAc with 0.10M NaOH. That is, NaOH is added to HAc. (a)pH at the beginning of titration. (b)pH at the equivalence point of the titration. (c) pH at the midpoint of the titration.
Tuesday, February 26, 2013 by Layla

chemistry 1B
1-propanol (P1° = 20.9 Torr at 25 °C) and 2-propanol (P2° = 45.2 Torr at 25 °C) form ideal solutions in all proportions. Let x1 and x2 represent the mole fractions of 1-propanol and 2-propanol in a liquid mixture, respectively, and y1 and y2 represent the mole ...
Tuesday, February 26, 2013 by Anonymous

Chemistry
Comment on the relative acidities of h3po4 and the h2po4 ion? I don't understand what this question is asking? Would H3PO4 is a strong acid and will completely dissociate into ions in aqueous solution suffice?
Tuesday, February 26, 2013 by Todd

Chemistry
The triprotic acid H3A has ionization constants of Ka1 = 6.8× 10–3, Ka2 = 8.1× 10–9, and Ka3 = 5.0× 10–12. Calculate the following values for a 0.0760 M solution of NaH2A [H+] = ? [H2A-]/[H3A]= ? Calculate the following values for a 0.0760 M ...
Tuesday, February 26, 2013 by Nancy

Chemistry
Phosphoric acid, H3PO4(aq), is a triprotic acid, meaning that one molecule of the acid has three acidic protons. Estimate the pH, and the concentrations of all species in a 0.100 M phosphoric acid solution. pKa1 = 2.16 pKa2 = 7.21 pKa3 = 12.32 [H3PO4] = ? [H2PO4-] = ? [HPO42...
Tuesday, February 26, 2013 by Nancy

Chemistry
What fraction of piperazine (perhydro-1,4-diazine) is in each of its three forms (H2A, HA–, A2–) at pH 7.22?
Tuesday, February 26, 2013 by Nancy

Chemistry
A certain indicator, HA, has a Ka value of 1.3 × 10-6. The protonated form of the indicator is blue and the ionized form is red. What is the pKa of the indicator? What is the color of this indicator in a solution with pH = 8? Blue, red, or purple?
Tuesday, February 26, 2013 by Nancy

chemistry
Calculate the theoretical yield (g) of precipitate formed when 10.0 mL of 0.50 M magnesium nitrate is added to 5.0 mL of 0.50 M potassium phosphate? [You must first write the balanced chemical equation.] Which reactant is present in excess?
Tuesday, February 26, 2013 by Joe

Analytical Chemistry
Show the predominant form of the amino acid tyrosine at pH=13.9 and ph=7.8. Be sure to include the proper number of hydrogens on heteroatoms and the correct formal charges on atoms. I calculated the pka values for COOH (pka=2.41) NH3 (pka=8.67), and OH (pka=11.01) but i'm...
Tuesday, February 26, 2013 by Sam

chemistry
why is HS- a stronger BL base compared to HSO4 In a series of oxybases with the same central atom, the base with more O atoms is stronger. In a series of oxybases with the same central atom, the base with less O atoms is stronger. Since H2SO4 is one of the seven strong acids, ...
Tuesday, February 26, 2013 by Hannah

Chemistry
In the formula 2C4H10+13O2=10H2O+8CO2 whats the mass of butane needed to produce 79.7g of carbon dioxide.
Tuesday, February 26, 2013 by Anonymous

Analytical Chemistry
You prepare a solution from 10.0 mL of 0.100 M MOPS buffer (3-morpholinopropane-1-sulfonic acid) and 10.0 mL of 0.086 M NaOH. Next, you add 1.00 mL of 8.87 × 10-4 M lidocaine to this mixture Denoting lidocaine as L, calculate the fraction of lidocaine present in the form...
Tuesday, February 26, 2013 by Sam

Analytical Chemistry
What fraction of piperazine (perhydro-1,4-diazine) is in each of its three forms (H2A, HA–, A2–) at pH 7.05? Not sure how to find k1 and k2 needed for the fraction formulas...please help :(
Tuesday, February 26, 2013 by Sam

Chemistry
what is the freezing point of 16.7g of LiCl in 136g of water, assuming complete dissociation for water kf= -1.86/mol
Tuesday, February 26, 2013 by Chloe

Chemistry
what is the freezing point of 16.7g of LiCl in 136g of water, assuming complete dissociation for water kf= -1.86/mol
Tuesday, February 26, 2013 by Chloe

Chemistry
what is the freezing point of 16.7g of LiCl in 136g of water, assuming complete dissociation for water kf= -1.86/mol
Tuesday, February 26, 2013 by Chloe

Chemistry
what is the freezing point of 16.7g of LiCl in 136g of water, assuming complete dissociation for water kf= -1.86/mol
Tuesday, February 26, 2013 by Chloe

chemistry
what is the structure of H2P2O6?
Tuesday, February 26, 2013 by nitesh solanki

Chemistry
A block of aluminum with a volume of 98.5 cm3 absorbs 67.4 J of heat. If its initial temperature was 32.5 °C, what is its final temperature? (density of aluminum = 2.70 g/cm3) I do not understand how to get the answer
Tuesday, February 26, 2013 by Mon

Chemistry
Identify the true statement about Lewis structures. Select all the correct answers. 1. Hydrogen is usually surrounded by 4 electrons in a valid Lewis structure. 2. A single bond in a Lewis structure represents 2 electrons. 3. A double bond in a Lewis structure represents 2 ...
Tuesday, February 26, 2013 by will.i.am

Chemistry
A block of aluminum with a volume of 98.5 cm3 absorbs 67.4 J of heat. If its initial temperature was 32.5 °C, what is its final temperature? (density of aluminum = 2.70 g/cm3) I do not understand how to get the answer
Tuesday, February 26, 2013 by Mon

Chemistry
Using the balanced equation of: HCl+NaOH-->H20+NaCl, how many moles of HCl could be neutralized with 13.2 mL of 3.00 M NaOH?
Tuesday, February 26, 2013 by Alicia

Chemistry
How many moles of NaOH are in 13.2 mL of 3.00 M NaOH?
Tuesday, February 26, 2013 by John

Chemistry
Would you expect the pressure of a 12.5 mL syringe of natural gas to be the same as the pressure of 12.5 mL of air? In other words, is Boyle's Law dependent on the type of gas that is being measured?
Tuesday, February 26, 2013 by Margaret

Chemistry
Are the following electrolytes or non-electrolytes? 1) CH3CH2CH2OH 2) Mg(OH)2 3) H3CO4CH3
Tuesday, February 26, 2013 by Rena

Chemistry
How many moles of magnesium sulfate are needed to make in a solution of 0.10g Mg2SO4?
Tuesday, February 26, 2013 by Rena

Chemistry
In the reaction 2H2O2(aq)-->2H2O2 + O2 (g), There is intially 0.865 M H2O2. After 10.0 minutes, the molarity of H2O2 changes to 0.792 M. What is the rate of reaction in terms of H2O2?
Tuesday, February 26, 2013 by Crystal

English
Commas: Do I need a comma between the words notes and so? - "Sitting at the sticky, crumb-covered cafeteria table, Luther and Ruth carefully studied their chemistry notes so that Dr. Wilson's next tricky test wouldn't confuse them." Do I need a comma between ...
Monday, February 25, 2013 by Sylvie

chemistry
What groups would be ionized in a solution of pH 12
Monday, February 25, 2013 by nena

Chemistry
at a pressure of 390.0 kPa, a sample of ideal gas containing 110. moles of propane is collected at a tempature of 55 degrees celcius. find the volume of the propane tank used
Monday, February 25, 2013 by Elizabeth

Chemistry
at a pressure of 390.0 kPa, a sample of ideal gas containing 110. moles of propane is collected at a tempature of 55 degrees celcius. find the volume of the propane tank used
Monday, February 25, 2013 by Elizabeth

chemistry
a sample of Ag2S has a mass of 62.4g. what mass of each element could be obtained by decomposing this sample?
Monday, February 25, 2013 by payton

chemistry
heating copper sulfate pentahydrate will evaporate the water from the crystals. leaving anhydrous copper sulfate,. a white powder. what mass of anhydrous CuSO4 would be produced by heating 500.0g of CuSO4*5H2O
Monday, February 25, 2013 by payton

Chemistry
A 205 mg sample of a diprotic acid is dissolved in enough water to make 250.0 ml of solution. The pH of this solution is 2.15. A saturated solution of calcium hydroxide (Ksp= 1.3 x 10-6) is prepared by adding excess calcium hydroxide to water and then removing the undissolved ...
Monday, February 25, 2013 by Summer

chemistry
calculate the percentage of water in each of the following hydrates SrCl2*6H2O
Monday, February 25, 2013 by payton

chemistry
which element is the most reactive in group 3? group 4?
Monday, February 25, 2013 by kazz

Chemistry
You have .5g of copper. If the nitric acid is 16 M HNO3, how many milliliters of nitric acid will react exactly with that amount of copper. I know that when I get that volume I will triple it so that there will be excess acid and the copper will be the limiting reactant.
Monday, February 25, 2013 by Morgan

Chemistry
You prepare a solution from 10.0 mL of 0.100 M MOPS buffer (3-morpholinopropane-1-sulfonic acid) and 10.0 mL of 0.083 M NaOH. Next, you add 1.00 mL of 5.77 × 10-5 M lidocaine to this mixture Denoting lidocaine as L, calculate the fraction of lidocaine present in the form...
Monday, February 25, 2013 by Bertha

Chemistry
if a gas is initially at 1.5 atm of pressure, Occupies a volume of 3.0 L at a tmepeature of 293K, what will be the new volume if the pressure increases to 2.5 atm and is now at 303K?
Monday, February 25, 2013 by Dustin

Chemistry
Explain how you would prepare 100.0 mL of 0.500 M NaCl solution. Include the appropriate glassware and calculations.
Monday, February 25, 2013 by Dee

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