Wednesday
May 25, 2016

Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

Chemistry
How do you find the formula for nitric acid?
Sunday, January 3, 2016 by Anonymous

Chemistry
What is the chemical formula and name when the following are added: 1. Na+1 Na-3 2. Na+1 Br-1 3. Na+1 O-2
Sunday, January 3, 2016 by Anonymous

chemistry
Based on mass spectrometer analysis of Uranium-235 and Lead-207, I have determined the age of a zircon to be 89.125 million years old. How many half-lives passed? What are the percentages of Uranium-235 and Lead-207?
Sunday, January 3, 2016 by HELP ME!! <3

Chemistry
The solubility of insoluble substances changes depending on the nature of the solution. Below are two solutions in which copper (II) hydroxide is dissolved; in each case, the solubility is not the same as it is in pure water. a. For each solution state whether the solubility ...
Sunday, January 3, 2016 by Marina

Chemistry
An iron nail with a mass of 0.750 g was dissolved in dilute sulfuric acid and diluted to 100.0 mL volume. A 10.0 mL aliquot of this solution was then titrated with standard 0.200 M potassium permanganate solution, according to the following equation: MnO4- + H+ +Fe2+ --> ...
Sunday, January 3, 2016 by Marina

chemistry
what is the advantage of using the indirect method over the direct method for calculating the enthalpy change of 2KHCO3 - K2CO3 + CO2 + H20
Sunday, January 3, 2016 by stephanie

chemistry
Explain the following statement. A saturated solution contains a mixture of silver chloride, AgCl and silver carbonate, Ag2CO3. An addition of hydrocloric acid will decrease the solubility of AgCl
Sunday, January 3, 2016 by oliver

chemistry
Explain the following statement. When aqueous ammonia is added to solution containing Pb2+ ions, a white precipitate is formed.
Sunday, January 3, 2016 by oliver

Chemistry
Q. How much of 80% alcohol should b mixed with 30ml of 95% alcohol in order to prepare 90% alcohol?
Saturday, January 2, 2016 by Vitthal

chemistry
why potassium permegnate is colourd
Saturday, January 2, 2016 by aiman

chemistry
why we add acid to the standardization of sodium thiosulphate solution?
Saturday, January 2, 2016 by aiman

chemistry
why we not use HNO3 and HCl in iodometry
Saturday, January 2, 2016 by aiman

chemistry
Please help me!!! Write a balanced chemical equation for oxidation-reduction reaction of fluorene
Saturday, January 2, 2016 by Yusuf

chemistry
A 90walt emersion heater is used to supply energy for 5min. The energy supplied is used to completely melt 160g of a solid at it's melting point.calculate the S.L.H of fusion of the solid.
Friday, January 1, 2016 by abdullahi yusuf

chemistry
an ionic bond will most likely form between elements from group_ a/2and3 , b/2and6 , c/3and4 , d/4and5 ,e/5and6
Friday, January 1, 2016 by barbie

Chemistry
What is the chemical formula and name for: Na+1 and Na-3?
Friday, January 1, 2016 by Anonymous

Science - Chemistry
If vapour pressure of water is 17.5 torr at 20C, what is the water vapour pressure inside a bottle of 100 proof whiskey? 100 proof = 50% ethanol Total volume = 1 L Mass of ethanol = 394.5g Mass of water = 500g Density of ethanol = 0.789g/mL Moles of ethanol = 8.58 mol Moles of...
Wednesday, December 30, 2015 by Sara

Chemistry
Are there any disadvantages of a mass spectrometer
Tuesday, December 29, 2015 by Kwadwo Ansah

chemistry
report on the preparation of 0.004M stock solution of ethanoic acid
Tuesday, December 29, 2015 by mercy

Chemistry
An experiment calls for 100ml of 0.1M copper(II) sulfate solution. Write a step-by-step procedure for a science teacher to make 100ml of 5M stock solution and the required diluted solution.
Tuesday, December 29, 2015 by Esther

Chemistry
How do you separate a mixture of iron fillings and sulphur powder by use of methylbenzene
Tuesday, December 29, 2015 by Ian

maths physics chemistry
State the principle on which each of the following is based. (a) the equation of continuity, Av = constant (b) the Bernoulli equation
Tuesday, December 29, 2015 by Joseph

chemistry
The solubility of a compound in water is 6.8g/100ml at 25°C. Calculate the amount of water required to crystallise 10g of the compound. If the pure compound is collected at 25°C what is the maximum possible yield percent?
Tuesday, December 29, 2015 by Amas

chemistry
How many grams of SrCl2 is required to prepare 1 molar solution of it,
Tuesday, December 29, 2015 by anitha

chemistry, physics please help
Calculate the molar enthalpy of solidification when 10.00KJ of energy are lost as 30.00g water are frozen at 0*C. i divided 30/18.02 =1.664 mol then, divided 10KJ/1.664mol =6.010 KJ/mol Am i correct? Thank you!
Monday, December 28, 2015 by miyabi

chemistry
A 250.0mL sample of 0.0012M Pb(No3)2 (aq) is mixed with 150.0mL of 0.0640M Na (aq) should precipitation of PbI2 (s) ,Ksp=7.1¡Á10^-9, occur?
Monday, December 28, 2015 by alfred

chemistry
If the titration of a 30.0 mL sample of sulfuric acid requires 27.65 mL of 0.090 M sodium hydroxide, what is the molarity of the acid? H2SO4(aq)+2NaOH(aq)→Na2SO4(aq)+2H2​O(l)
Sunday, December 27, 2015 by lisa

Chemistry
the pH of a solution is 10 and other is 12 when equal volumes of these low are mixed the pH of the resulting solution is?
Sunday, December 27, 2015 by Pandu

Chemistry
Reaction of gaseous fluorine with compound x yields a single product y, whose mass percent composition is 61.7% F and 38.3%Cl. (a) What is a probable molecular formula for product Y, and what is a probable molecular formula for X? (b) Draw an electron-dot structure for Y, and ...
Saturday, December 26, 2015 by Malan

Chemistry
Enter the formulae of the products and give their states. Type your answer using the format Na2SO4(aq) for Na2SO4(aq). Do not balance the equation. If there are no products, enter "none". ZnCO3(s) + heat ---> I know it's a decomposition reaction, so I thought ...
Thursday, December 24, 2015 by Anna

chemistry
Report the preparation of stock solution of 0.04M of sulphoric acid
Thursday, December 24, 2015 by edache

Chemistry
Based on mass spectrometer analysis of Uranium-235 and Lead-207, I have determined the age of a zircon to be 89.125 million years old. How many half-lives passed? What are the percentages of Uranium-235 and Lead-207?
Tuesday, December 22, 2015 by Anonymous

Chemistry
The carbon buried in a peat bed has about 12.5% of the Carbon-14 of modern wood. What is the age of the peat bed? Explain?
Tuesday, December 22, 2015 by Anonymous

chemistry
Which among hydride, methyl or phenyl shift is the most preferred?
Tuesday, December 22, 2015 by Rajat

Chemistry
Take the reaction: NH3 + O2 ---> NO + H2O. In an experiment, 3.25 g of NH3 are allowed to react with 3.50 g of O2. Which reactant is the limiting reagent? You may either write the formula or the name of the limiting reactant.
Monday, December 21, 2015 by Ayame

Chemistry
How would you prepare the ff. solutions: 1. 45g NaCl/g H2O 2. 25% w/v NaCl Thank you in advance.
Monday, December 21, 2015 by JamesKim

chemistry
The maximum allowable concentration of Pb2+ ions indrinking water is 0.05 ppm (that is, 0.05 g of Pb2+ in 1million g of water). Is this guideline exceeded if an undergroundwater supply is at equilibrium wiht the mineral anglesite,PbSO4 (Ksp=1.6 x10-8)?
Monday, December 21, 2015 by Malan

Chemistry
What is the ionic strength of 0.2 M Na2HPO4 in a solution?
Monday, December 21, 2015 by Raj

Chemistry
How do shape and symmetry influence the polarity of a molecule?
Sunday, December 20, 2015 by Faith

Chemistry
Analysis of a sample of an organic compound showed it contains 39.9%carbon,6.9%hydrogen and 53.2%oxygen. a)calculate the empirical formula b)if the relative molecular mass is 60,what is the molecular formula of the compound.(C=12,H=1,O=16)
Saturday, December 19, 2015 by Angel

Chemistry
An organic compound on analysis gives the following percentage composition of elements present. Carbon 61.85%,hydrogen 10.50% and oxygen 27.65%.determine the empirical formula of the compound.(C=12,H=1,O=16)
Saturday, December 19, 2015 by Angel

Chemistry help
The earth moves round the sun in one year.the average earth-sun distance is 1.5*10^11m given that the mass of the earth is 5.98*10^24kg (a):the angular momentum of the earth??? (b):kinetic energy of the earth motion?? (c):kinetic energu of the earth motion half way along it ...
Friday, December 18, 2015 by Collins

Science chemistry
a steel cylinder of oxygen with a volume of 15 L was available for medical purposes. The cylinder pressure decrease from 40.6 to 38.5 atm during which time the temperature remain at 24.0 °C how many moles of oxygen had been removed
Friday, December 18, 2015 by Hiba

Chemistry
The reaction N2O4(g) -->2NO2(g) has Kc = 0.133 at 25 °C. What is the NO2 concentration in a 5.00 liter flask if it contains 0.250 mol of N2O4 at equilibrium I know I set something equal to Kc?
Thursday, December 17, 2015 by Anonymous

Chemistry
what volume of 0.1M HCl would be needed to neutralize 0.35M NaOH to a 100ml volume?
Thursday, December 17, 2015 by Elisha

CHEMISTRY
^H FOR CS2+3O>CO2+2SO2
Thursday, December 17, 2015 by FRANCISCO

chemistry
how long would it take a 250# block of ice to melt in a room of 68 deg F
Thursday, December 17, 2015 by joyce

chemistry, physics
What is the most important source of error in the calorimeter experiment? I know few, but I don't know what is the most important source of error. Stirring error the calorimeter is not properly insulated Calculation error Measurement error in volume and or weight
Wednesday, December 16, 2015 by miyabi

chemistry, physics
How would you be able to utilize a calorimeter to determine the specific heat of substance that has a lower density than water?
Wednesday, December 16, 2015 by miyabi

chemistry, physics
In the specific heat measurement does the sample have to be 100 C, or would a lower initial temperature do just aa well? I wrote down it doesn't matter, but i don't know why.
Wednesday, December 16, 2015 by miyabi

chemistry, physics
When measuring specific heat, why should your final temperature be the maximum temperature reached calorimeter?
Wednesday, December 16, 2015 by miyabi

chemistry
Calculate the pH of a solution that is made up to contain the following analytical concentrations : 0.05 M in H3PO4 and 0.02 M in NaH2PO4
Wednesday, December 16, 2015 by sharwin

chemistry
explain the effect of the nitrate/sulfate/chloride ion when chemically combined witha metal on the color emission?
Tuesday, December 15, 2015 by Dericka

Language Arts
Hi guys, can someone help me with three questions? 1. Which word best completes the sentence? I am going to ___ my chemistry teacher to learn more about careers in science. a. investigate b. discover c. interview d. evaluate Is it d or c? Or neither? 2. Which of the following ...
Tuesday, December 15, 2015 by Samantha

Chemistry
A 4.05L sample of argon, initially at STP is heated to 500k. The final volume is 6.5L. Determine the final pressure in atm.
Tuesday, December 15, 2015 by Ismari

Language Arts
Hi guys, can someone help me with three questions? 1. Which word best completes the sentence? I am going to ___ my chemistry teacher to learn more about careers in science. a. investigate b. discover c. interview d. evaluate 2. Which of the following sentences contains an ...
Tuesday, December 15, 2015 by Samantha

Chemistry
A chemical technician prepares Ni(NH3)6Cl2 by adding 4.55 g of solid NiCl2·6H2O to 25 mL of 6.0 M aqueous NH3. What is the maximum mass of Ni(NH3)6Cl2 that will be produced? how would I do this question?
Monday, December 14, 2015 by Dan

Chemistry
I'm doing a lab in chemistry and I need help with a question, here is my data: Mass Before: 26.4 g After burned: 26.25 g Total Mass burned: .15 g 1. Calculate the mass of oxygen that was consumed while the candle burned. I think I need to use mole equations and that kind ...
Monday, December 14, 2015 by Patti

Chemistry
you need to prepare 100 ml of ph=3.50 buffer solution using 0.100 M formic acid and 0.200 M sodium formate. how much of each solution shoudl be mixed to prepare this buffer?
Monday, December 14, 2015 by Navi

Chemistry
How many g of CaCl2 are required to prepare 0.250 L of a 0.200 M solution?
Sunday, December 13, 2015 by Aaron

CHEMISTRY
what is the percent by mass of solution (d =1,3g/ml) of urea ((NH2)2CO) with molarity 8,4mol/l?
Sunday, December 13, 2015 by EDWARD,ESOBUNETA

Chemistry
How many calcium atoms are in a formula unit of calcium hydrogen carbonate? 1. 1 2. 2 3. 4 4. 3 5. 5
Sunday, December 13, 2015 by C

chemistry
If a solution of barium hydroxide contains 9.1x1025 hydroxide ions, how many grams of barium hydroxide were originally dissolved?
Sunday, December 13, 2015 by Anonymous

AP Chemistry
Calculate the delta H rxn for the following reaction: CH4(g)+4Cl2(g)-->CCl4(g)+4HCl Use the following reactions and given delta H's: 1) C(s)+2H2(g)-->CH4(g) delta H= -74.6 kJ 2) C(s)+2Cl2(g)-->CCl4(g) delta H= -95.7 kJ 3) H2(g)+Cl2(g)-->2HCl(g) delta H= -184.6 ...
Sunday, December 13, 2015 by Caitlyn

CHemistry
the standard entalpy of combustion of ethene gas C2h4 IS -1411.1 KJ/mol at SATP. Calculate Hf for ethene gas. my work so far: C2H4 +302--> 2C02 +2H20 H=[(2mol)(-241.8kj/mol)+(2)(-393.5)]-[x]​ -1411.1kj/mol=-1270.6-x x=-1270.6+1411.1 Ans: 52.5 kj which I can't get to
Saturday, December 12, 2015 by Joce

math
in chemistry class, todd has 1 liter of a 23% sulfuric acid solution, how much of a 15% sulfuric acid solution must he mix with the 1 liter of 23% solution to make a 18% solution?
Saturday, December 12, 2015 by sup

Chemistry
Why do the alkali metals have low ionization energies but large atomic radius?
Saturday, December 12, 2015 by Anonymous

chemistry
the number of moles in 12.04x10^23 molecules of Oxygen
Saturday, December 12, 2015 by kevin

Chemistry
Compute the number of molecules of water driven off when 12.05g of sodium acetate trihydrate is heated.
Saturday, December 12, 2015 by Anon

Chemistry
Suppose we had mixed 52.37 mL of 1.00 M HI solution with 25.42 mL of 1.00 M KOH solution, and measured a heat of reaction of -1.52 kJ. What is ΔH for this reaction, in kJ? Assume that all solutions have the same density as water (1.00 g/mL).
Friday, December 11, 2015 by Will

Chemistry
At its normal boiling point of 126°C n-octane, C8H18, has a vapor pressure of 760 torr. What is its vapor pressure at 25°C? the enthalpy of vaporization of n-octane is 39.07 kj/mol.
Friday, December 11, 2015 by Nicole

Chemistry
Rank the following in order of increasing vapor pressure at 298 k: CH3CH2OH, CH3OCH3, CH3CH2CH3.
Friday, December 11, 2015 by Nicole

Chemistry
how many milliliters of a 2.61 m h2so4 solution are needed to neutralize 71.50 ml of a 0.855 m koh solution
Friday, December 11, 2015 by Patty

Chemistry
how many milliliters of a 2.61 m h2so4 solution are needed to neutralize 71.50 ml of a 0.855 m koh solution
Friday, December 11, 2015 by Anonymous

Chemistry
If you reacted 100.0 g of carbon tetrachloride (CCl4) with excess antimony fluoride (SbF3), how many grams of carbon dichloride difluoride would be produced?
Friday, December 11, 2015 by Catherine

Chemistry 12
The molar heat of vaporization of water is 42 kJ/mol. How much energy is released by the condensation of 3.0 g of water? So for water there will just be one mol. I think this is how you do it, but it doesn't match the answer in the worksheet. q=mc delta t But we're not...
Thursday, December 10, 2015 by Rachel

Chemistry
please balance this chemical equation iron +oxygen > iron (III) oxide +energy Fe + O2> Fe2 O3 + heat and light
Thursday, December 10, 2015 by Donald

Chemistry
is delta S positive for the heating of water from 25 to 75 degrees Celsius?
Thursday, December 10, 2015 by john

Chemistry
How can i synthensize 1g of salicylic acid from Phenol
Thursday, December 10, 2015 by Adeola

Chemistry
How can i synthensize 1g of salicylic acid from benzene
Thursday, December 10, 2015 by Adeola

General Science/ Chemistry
Is it necessary to know the exact volume of the “unknown” acid or base to be titrates.
Thursday, December 10, 2015 by Mark

Chemistry
Why do the alkali metals have low ionization energies but relatively large atomic size? (I thought larger atomic sizes meant higher ionization energies.) What is the relationship between the two?
Thursday, December 10, 2015 by Anonymous

Chemistry
If a basic solution has a pH of 11.88, is it considered to be a strong base? Is an acidic solution with a pH of 4.44 considered to be a strong acid?
Thursday, December 10, 2015 by Jessica

chemistry
A reagent bottle contains 5.00g of NaOH.how many milliliters of a 2.00M silution can be prepared from this weight of NaOH?
Thursday, December 10, 2015 by Anonymous

Chemistry
A 100.0-mL sample of air is collected at 21 degrees Celsius and 772 mm Hg. What is the volume of air at STP? I know that I have to change deg. Celsius to K and mm Hg to atm. I'm stuck on what formula I should use... Should I use PV=nRT?
Thursday, December 10, 2015 by Jason

chemistry
How many Lithium ions are in 75.3 grams of lithium sulfate?
Thursday, December 10, 2015 by Anonymous

Chemistry
My question is: What is the mass of solute in a 25.0 g of 10.0 %(m/v) sucrose solution? (Assume density of solution is 1.15 g/mL) I was wondering if my answer: 2.17 g solute is correct? Thank you
Wednesday, December 9, 2015 by Cece

Chemistry 12
"Add the ionic equations for part one and three, compare the results with the ionic equation for part two" Part 1: NaOH(s) = Na+(aq) +OH-(aq) + heat Part 2: NaOH(s) + H+(aq) +Cl-(aq) = Na+(aq) + Cl-(aq) + H2O(l) + heat Part 3: Na+(aq) + OH-(aq) + H+(aq) + Cl-(aq) = ...
Wednesday, December 9, 2015 by Avery

Chemistry
What mass of lead (II) sulphate would be produced by the action of excess dilute sulpuric acid on 10 g of lead nitrate dissolved in water? I need help, at least an example.
Wednesday, December 9, 2015 by Jaevon

Chemistry
A solution containing 22.18 mL of a .1212 M H2CO3 solution is mixed with 17.22 mL of a .1234 M Na2CO3 solution. What is the pH of the final mixture? Ka1 = 6.2x10-7 Ka2 = 4.4x10-11. If you diluted the mixture up to 100 mL, would the pH change? If it does change, what would the ...
Wednesday, December 9, 2015 by Jill

Chemistry
Citric acid is a tri-protic acid with a Ka1 =8.4x10-4 Ka2=1.8x10-5 and Ka3=4.0x10-6. calculate the pH at the 2nd equivalence point in the titration of 85.5 mL of a .21 M citric acid solution with .25 M NaOH. Calculate the pH, after 25.8 mL of NaOH have been added. Calculate ...
Wednesday, December 9, 2015 by Jill

Chemistry
a 5.000ml aqueous sample containing hydrogen peroxide as diluted to 25ml and analyzed by titration with permanganate. 2MnO4- + 5H2O + 6H+ --> 5O2 + 2Mn^2+ + 8H2O The sample required 42.8 mL of 0.0175 M permangante to reach the end point. What is the concentration of H2O2 in...
Wednesday, December 9, 2015 by Sarah

Chemistry
Alloys of copper and zinc are used to produce brass. Why do these elements not react in this application?
Wednesday, December 9, 2015 by Tom

Chemistry
Calcuate the tatla volme of gas (at 45c and 785mmHg) producedbby the complete decmpotition of 2.55kg of ammoniium nitrate.
Wednesday, December 9, 2015 by Teisha

Chemistry
A sample of nitrogen gas was collected via water displacement. Since the nitrogen was collected via water displacement, the sample is saturated with water vapor. If the total pressure of the mixture at 21 °C is 1.16 atm, what is the partial pressure of nitrogen? The vapor ...
Wednesday, December 9, 2015 by Leanna

Chemistry
A sample of nitrogen gas was collected via water displacement. Since the nitrogen was collected via water displacement, the sample is saturated with water vapor. If the total pressure of the mixture at 21 °C is 1.16 atm, what is the partial pressure of nitrogen? The vapor ...
Wednesday, December 9, 2015 by Leanna

Chemistry
I have to list distributed benzene in order of polarity, and I don't think i know how to do that, but does polarity have to do with dipole moments?
Wednesday, December 9, 2015 by Dan

Chemistry
I just need someone to check over my answers, I'm pretty confident in all of them! In which six-membered hydrocarbon rings are all of the C-C-C angles roughly the same, i.e., within 1o? Select ALL that apply. Question 1 options: A)cyclohexane B)cyclohexene C)1,3-...
Wednesday, December 9, 2015 by Dan

chemistry
C2H6 <> C2H4 + H2. when 1.00mol ethane is cracked at 180kPa and 1000K, the yield of ethene is 0.36mol. Calculate the value Kp at 1000K...
Wednesday, December 9, 2015 by jay

Chemistry (Help)
I'm having trouble figuring out this one. Can you please help? I haven't gotten a response to any of my questions. Chemical formula: Na Name: Sodium Bond Type (intramolecular FOA): metallic bond VSEPR molecular shape: none Central Atom Hybridization: none? Molecular ...
Wednesday, December 9, 2015 by Kyle

  1. Pages:
  2. <<Prev
  3. 13
  4. 14
  5. 15
  6. 16
  7. 17
  8. 18
  9. 19
  10. 20
  11. 21
  12. 22
  13. 23
  14. 24
  15. 25
  16. 26
  17. 27
  18. Next>>

Homework Help: Science