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February 8, 2016

Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

Chemistry-Dr.Bob
An unknown piece of metal weighing 100. g is heated to 90.0 degrees Celcius. It is dropped into 250 g of water at 20.0 degrees Celcius. When equilibrium is reached, the temperature of both the water and piece of metal is 29.0 degrees Celcius. Determine the specific heat of the...
Saturday, January 9, 2016 by Sanaya

chemistry
Is bp of para and meta and ortho isomer are same
Saturday, January 9, 2016 by debobrata

Chemistry
calculate the initial concentration of HCOONa you would add to 0.10M HCOOH to make a buffer with a pH of 4.00 [Ka (HCOOH) = 1.8 x 10^-4]
Saturday, January 9, 2016 by Christabel

chemistry
explain why metal oxides tend to be basic if the oxidation number of the metal is low and acidic if the oxidation number of the metal is high
Saturday, January 9, 2016 by Faye

Chemistry
100 mL 0.1 M sodium acetate solution is mixed with 50 mL 0.1 M acetic acid. If now 0.937 mL of 1 M sodium hydroxide is added to the buffer what is the change in pH? pKa (acetic acid) = 4.76
Saturday, January 9, 2016 by Jamie

Chemistry
reacting 3 mol C4H10 and 12 mol O2 will occur as a complete combustion, true or false
Saturday, January 9, 2016 by RN

Chemistry
The standard free energy of formation of nitric oxide, NO, at 1000. K (roughly the temperature in an automobile engine during ignition) is 77.5 kJ/mol. Calculate the equilibrium constant for the reaction
Saturday, January 9, 2016 by Anonymous

chemistry
55 gm laughng gas contains ---------gm N.
Saturday, January 9, 2016 by G.raju

chemistry
If 6.00g of carbon is heated in air, the mass of the product obtained could either be 22.0g or 14.6g depending on the amount of air present. Using calculations with what law will this be in accordance?
Saturday, January 9, 2016 by Divine phyavuh

Chemistry
20.0 mL of ethanol initially at 7.2 degrees Celsius is mixed with 31.7 mL of water initially at 28.9 degrees Celsius in an insulated beaker. Assuming no heat is lost, what is the final temp? I did not include the density, but I solved for mass, and have the SHC, for both. Don...
Friday, January 8, 2016 by Jennifer

chemistry
what is the total number of atoms in the compound (NH4)3PO4?
Friday, January 8, 2016 by Cayden

Chemistry
Will 100g of copper completely replace all the silver in 200g of silver nitrate
Friday, January 8, 2016 by T

Chemistry-Dr.Bob, I need you!!!!
You can mix 100.mL of 1.0 M HCl with 100 mL of 1.0 NaOH, both at 25 degree Celcius. The temperature of your calorimeter rises by 5.98 degree C, and its heat capacity is 100 J/degre C. How much energy is released per mol of H2O formed? My answer: 6x10^6 J per mol H2O I think we...
Friday, January 8, 2016 by Sanaya

Chemistry-Dr.Bob
You can mix 100.mL of 1.0 M HCl with 100 mL of 1.0 NaOH, both at 25 degree Celcius. The temperature of your calorimeter rises by 5.98 degree C, and its heat capacity is 100 J/degre C. How much energy is released per mol of H2O formed? My answer: 6x10^6 J per mol H2O
Friday, January 8, 2016 by Sanaya

chemistry
200cm3 of each of 0.1m of solutions of lead (ii) trioxonitrate (v) and hydrochloric acid were mixed. Assuming that lead (ii) chloride is completely insoluble, calculate the mass of lead (ii) chloride that will be precipitated.
Friday, January 8, 2016 by joshua

chemistry
What mass of NaHCO3 must be added to 100ml H2O to produce a solution with a pH of 10? K1(H2CO3)=4,6*10^-7 K2(H2CO3)=4,4*10^-11 -------- Help! Thank you
Thursday, January 7, 2016 by Sonia

basic chemistry
different ways to split a mixture of benzene into components using two phase system separation
Thursday, January 7, 2016 by shivani

Chemistry
Calculate pH and concentration of H2SO3, H2SO3- and SO32- in NaHSO3 c=0,05M. Ka1= 1,23*10^(-2) Ka2= 6,6*10^(-8) Results attached are: a) [H2SO3]= 1,04x10-4 M, [SO32-]=1,3x10-4 M, [HSO3-]= 0,05 M but i keep getting different numbers.
Thursday, January 7, 2016 by Anna

Chemistry
Compound X contains only carbon, hydrogen, nitrogen, and chlorine. When 1.00 g of X is dissolved in water and allowed to react with excess silver nitrate, AgNO3, all the chlorine in X reacts and 1.95 g of solid AgCl is formed. When 1.00 g of X undergoes complete combustion, 0....
Wednesday, January 6, 2016 by Anonymous

Chemistry
Compound X contains only carbon, hydrogen, nitrogen, and chlorine. When 1.00 g of X is dissolved in water and allowed to react with excess silver nitrate, AgNO3, all the chlorine in X reacts and 1.95 g of solid AgCl is formed. When 1.00 g of X undergoes complete combustion, 0....
Wednesday, January 6, 2016 by Sarah

Chemistry
Which molecule would be more soluble in water ? H----C=C---H or BeCl2
Wednesday, January 6, 2016 by Ali

Chemistry
Substances A and B, initially at different temperatures, come in contact with each other and reach thermal equilibrium. The mass of substance A is twice the mass of substance B. The specifi c heat capacity of substance B is twice the specifi c heat capacity of substance A. ...
Wednesday, January 6, 2016 by Anonymous

Chemistry
How do you calculate the number of moles and atoms of magnesium given the number o grams of magnesium chloride?
Wednesday, January 6, 2016 by Anonymous

Chemistry
Arrange the following compounds in order of increasing Boiling point: CH4, CHCl3, CCl4, CH3Cl
Wednesday, January 6, 2016 by Naaz

Chemistry
1. Convert 1.2 X 10^24 molecules of chlorine to grams. Ans: 70.67 gms
Wednesday, January 6, 2016 by Anonymous

Biology/Chemistry
Does anybody know how much 1 mole of acid should be diluted in order to mimic the pH of acid rain? I also need sources, but haven't been successful in any of my searches so far, thanks.
Wednesday, January 6, 2016 by Alice

Gratitude for my helper
Sir steve mrs reiny sir bobpursely sir damon ms sue..... Thank you very much you guyz have really help me alot today my result came out and i score 98 out of 100 in my maths exams aldo i am still shaking in my english but with the help of ms sue i always read english question ...
Wednesday, January 6, 2016 by Collins

Chemistry:normal notation plz help
Using the normal notation of quantum number find the element which has the following value of quantum number n=3 l=2 m=2 s=+1/2 (a):potassuim (b):nitrogen (c):sodium (d):scandium
Wednesday, January 6, 2016 by Collins

7th grade math
A biology class has 28 students. Four of the students transferred out to take chemistry. Find the percent of change in the number of students in the biology class. I got 86 percent change is that right? Thank you...My mom says it's 14.3 %
Tuesday, January 5, 2016 by Peggy

chemistry
I am wondering why H2S has only London Dispersion forces and not Hydrogen Bonding?
Monday, January 4, 2016 by David

chemistry
state what happens when chlorine is bubbled through Iron(II) sulphate solution .
Monday, January 4, 2016 by Anonymous

Chemistry
What is pH if 0.02M NaOH is added to buffer solution, consisting 0.4M aqueous NH3 & 0.3M NH4Cl(Kb=0.000018)
Sunday, January 3, 2016 by Solution

Chemistry
When 31 g of a metal at 88 ◦C is added to 46 g of water at 27 ◦C, the temperature of the water rises to 34 ◦C. What is the specific heat capacity of the metal? Assume no heat was lost to the surroundings. Answer in units of J / g ·◦C.
Sunday, January 3, 2016 by Amy

Chemistry
1.10 g of glucose was completely burnt in a copper calorimeter. The temperature of the water increased from 25.85 °C to 36.50 °C.
Sunday, January 3, 2016 by Khairavi

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

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Homework Help: Science