Saturday
February 13, 2016

Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

Chemistry
In March 2007 a number of pets were sickened or killed by pet food contaminated with the chemical melamine, which is used in the manufacture of certain plastics. It is thought that the melamine was added to make a pet food additive appear to have more protein than it really ...
Tuesday, October 13, 2015 by Anonymous

Chemistry
I have a lab question that is asking if the soda ash in our analysis was NaHCO3 instead of Na2CO3, how would the volume of acid added change from (a) the starting point to the phenolphthalein end point? (b) the phenolphthalein end point to the bromocresol green end point? (c) ...
Tuesday, October 13, 2015 by Rachel

Chemistry
A compound frequently used as a high-temperature lubricant has the formula MS2, where M represents some metallic element. If this compound is 40.06% sulfur by mass, what is the identity of the metal M? I'm confused on how to figure this out.
Tuesday, October 13, 2015 by Anonymous

Chemistry (Check)
Nitrogen combines with oxygen to form a variety of compounds. One of these compounds is called nitrous oxide or "laughing gas." What is the formula of nitrous oxide if this compound is 63.65% N and 36.35%O by weight? I got N2O
Tuesday, October 13, 2015 by Anonymous

chemistry
Deterioration of buildings, bridges, and other structures through the rusting of iron costs millions of dollars everyday. Although the actual process also requires water, a simplified equation (with rust shown as iron(III) oxide (Fe2O3) is: 4Fe(s)+3O2(g) --> 2Fe2O3(s) ...
Tuesday, October 13, 2015 by patrick

Chemistry
How many hydrogen atoms are in a 15.00 mg sample of glucose? (C6H1206)
Tuesday, October 13, 2015 by Debbie

Chemistry
There is a question on my assignment that's asks how many moles of atoms are in x mol of CO2 (and a few others). Let X represent 5x10^-4. How do I do this? Teacher didn't really teach us this. I know in one mol of CO2 there is 2 moles of oxygen atoms, so how many in ...
Tuesday, October 13, 2015 by Logan

Chemistry
A water treatment plant adds fluoride ion to the water to the extent of 1.5mg F-/L H2O. a)What is the molarity of fluoride ion in this water? b)If the fluoride ion in the water is supplied by calcium fluoride, what mass of calcium fluoride is present in 1.00 x 10^6 L of this ...
Tuesday, October 13, 2015 by Faith

chemistry
Dr. Bob.. 630.24 kj was marked wrong...it said hint: make sure to carry out dimensional analysis........ ÄH value refers to the amounts of (moles) of substances and their matter in that specific equation. help....please....
Tuesday, October 13, 2015 by patrick

chemistry
Consider the following balanced thermochemical equation for a reaction sometimes used for H2S production: 1/8 S8 (s) + H2 (g) ¨ H2S (g) ƒ¢Hrxn = -20.2 kJ (a)Is this an exothermic or endothermic reaction? (b)What is ƒ¢Hrxn for the reverse reaction...
Tuesday, October 13, 2015 by patrick

Chemistry
Which of the following procedures involves a physical change in one of the substances? separating an oil from solution by cooling it<--- my answer allowing a nail to rust creating salt by reacting sodium metal and chlorine gas building a model rocket propelled by mixing ...
Tuesday, October 13, 2015 by Sara

chemistry
A 49.3 g sample of ethylene glycol, a car radiator coolant, loses 624. J of heat. What was the initial temperature of ethylene glycol if the final temperature is 32.5°C (c of ethylene glycol = 2.42 J/gK)? 624= 49.3 x 2.42(T-32.50) T = 37.73 = 38degrees is this correct? ...
Tuesday, October 13, 2015 by patrick

Chemistry
The apparatus contains methane and oxygen at a temp of 383K. Here is the reaction: CH4(g) + 2O2(g) --> CO2(g) + 2H2O(g) solve for final pressures of all species and the final total pressure, For CH4 the volume = 1.164L the pressure = 6atm For O2 the volume = 0.827L the ...
Tuesday, October 13, 2015 by Terry

chemistry
A reaction mixture of 4.0 mL of 0.002 M SCN- and 5.0 mL of 0.002 M Fe3+ is diluted to 10.0 mL with 0.1 M HNO3 to form the blood-red FeNCS2+ complex. The equilibrium molar concentration of the FeNCS2+ determined from a standardization curve is 1.5x10^-4 mol/L. Calculate, in ...
Tuesday, October 13, 2015 by Anonymous

Chemistry
What is the pH of a 0.0050 M solution of sodium fluoride? I got 7.58 for pH. Is it correct? but I try to plug in my quadratic formula, I don't get the pH 7.58. I'm really confuse. Please help.
Monday, October 12, 2015 by Matt

Chemistry
According to the balanced equation below, how many moles of KBr will be made from 30.0 mL of 1.00 M HBr solution? HBr(aq) + KOH(aq) --> H2O(I) + KBr(aq)
Monday, October 12, 2015 by Minset

Chemistry
When 22.3 mL of 1.00 M AgNO3 is mixed with 21.7 mL of 1.50 M NaCl, the temperature of the mixture rises for 21.6 degrees C to 29.7 degrees C. The mass of the aqueous mixture is 45.9 grams and its specific heat capacity is 3.94 J/grams degrees C. I calculated (45.9g)x (3.94J/g ...
Monday, October 12, 2015 by Sarah

Chemistry
Tums tablets contain CaCO3 that reacts with stomach acid as follows: CaCO3 (s) + 2HCl (aq) → CaCl2 (aq) + H2O (l) + CO2 (g)  Suppose the tablet was analyzed by adding 50.00 mL of 0.200 M HCl, which resulted in leftover excess HCl. The excess HCl was then analyzed...
Monday, October 12, 2015 by CHIPNDALE

Chemistry
A student determines the freezing point of a solution of 1.96g of naphthalene in 25.64g of paradichlorobenzene(PDB). The following temperature-time reading are recorded. PDB/Napthalene Time(Min) 0 0.5 1.5 2 2.5 3 3.5 4 4.5 Temp(°C) 59.7 58.0 54.8 53.4 52.1 50.9 49.5 49.6 ...
Monday, October 12, 2015 by Lisa

Chemistry
A student determines the freezing point of a solution of 1.96g of naphthalene in 25.64g of paradichlorobenzene(PDB). The following temperature-time reading are recorded. PDB/Napthalene Time(Min) 0 0.5 1.5 2 2.5 3 3.5 4 4.5 Temp(°C) 59.7 58.0 54.8 53.4 52.1 50.9 49.5 49.6 ...
Monday, October 12, 2015 by Lisa

Chemistry
Imagine that you have a 7.00 L gas tank and a 4.50 L gas tank. You need to fill one tank with oxygen and the other with acetylene to use in conjunction with your welding torch. If you fill the larger tank with oxygen to a pressure of 136 bar , to what pressure should you fill ...
Monday, October 12, 2015 by Emily

Chemistry
1.how many total oribitals are present in quantum #1 2. How many electrons are possible in quantum level 1 3. How many total or initials are present in quantum level 3
Monday, October 12, 2015 by Sam

chemistry
what does this mean: is (a molecule) sigma or pi in symmetry? the molecule in question is c triple bond c. ....it has 2 pi bonds and 1 sigma bond....which is symmetrical?
Monday, October 12, 2015 by paul

Chemistry
1. what reaction take place when water is passed through anion exchange resin ? 2. how much na2co3 or salked lime should be added to completely 300cm^3 of 2percent cacl2 solution ?
Monday, October 12, 2015 by Saszuuu

chemistry
how much oxygen gas wil be produce from the decomosition of 50 grams of pottasium chlorate
Monday, October 12, 2015 by JC

Chemistry
What volume of 0.149 M HCl must be added to 1.00x10^2 mL of 0.285 M HCl so that the resulting solution has a molarity of 0.205 M? Assume that the volumes are additive.
Monday, October 12, 2015 by Faith

Chemistry
I am told to find the "Total heat capacity of the system in the Calorimeter" All I have is this equation: Csys=Ccal+Csol What is this Csys? and how do I figure out how to use this equation? Thankyou
Monday, October 12, 2015 by Adam

Chemistry
Suppose that atomic masses were based on the assignment of a mass of 12.000 g to 1 mol of carbon, rather than 1 mol of ^12C. What would the atomic mass of oxygen be? (The atomic masses of carbon and oxygen based on the assignment of 12.000 g to 1 mol of ^12C are 12.011 amu and...
Sunday, October 11, 2015 by Anonymous

Chemistry
Neutron stars are composed of solid nuclear matter, primarily neutrons. Assume the radius of a neutron is approx. 1.0 x 10^-13 cm. Calculate the density of a neutron. [Hint: For a sphere V=(4/3) pi r^3. Assuming that a neutron star has the same density as a neutron, calculate ...
Sunday, October 11, 2015 by Anonymous

Chemistry
Nitric acid, HNO3, is produced from ammonia and oxygen by the consecutive reactions: 4NH3 + 5O2 => 4NO3 + 6H2O 2NO + O2 => 2NO2 3NO2 + H2O => 2HNO3 + NO How many grams of nitric acid can be obtained from 1.00kg NH3 if NO in the third reaction is not recycled? Why is ...
Sunday, October 11, 2015 by Faith

Chemistry
An alpha particle, ^4 He^2+, has a mass of 4.00151 amu. Find the value of its charge-to-mass ratio in C/kg.
Sunday, October 11, 2015 by Anonymous

chemistry
A ground state hydrogen atom absorbs a photon of light having a wavelength of 93.73 nm. It then gives off a photon having a wavelength of 1094 nm. What is the final state of the hydrogen atom?
Sunday, October 11, 2015 by michelle

chemistry - HELP!
The equilibrium constant, Kc, for the reaction A(g) + B(g) <-->AB(g) is 115 at 25 degrees C. If 1.580 x 10^(‐1) mol of A and 4.721 x 10^(‐5) mol of B are introduced into a 1.00 liter vessel at 25 degrees C, calculate the equilibrium concentration of all ...
Sunday, October 11, 2015 by Sheri

Chemistry
glycine + valine-->glycine - valine+H2O What happens with this reaction and where does water molecule come from
Sunday, October 11, 2015 by Sharon

Chemistry
Reaction: C6H11OH(l) ==> C6H10(l) + H2O(l) Calculate the mass of cyclohexanol (C6H11OH) needed to produce 45.0g cyclohexene (C6H10) by reaction if the reaction has a 86.2% yield and the cyclohexanol is 92.3% pure. Usually this problem would be fairly easy, but the purity is...
Sunday, October 11, 2015 by Faith

Chemistry
Potassium permangenat reacts with sodium oxalate to form carbon dioxide and Mn2+.determine the consentration of a permangenate solution.since the reaction runs in acidic conditions, 25ml of 2 M sulfuric acid was added to 20.00ml of the unknown permangenate solution. It was ...
Sunday, October 11, 2015 by Aida

algebra
A chemistry lab wants to prepare 300 liters of 25% acid solution. In stock he has 20% and 35% acid solutions. How many liters of each in stock mixture should he mix tp prepare a 300-liter mixture?
Sunday, October 11, 2015 by Anonymous

Chemistry
Why does the height of the precipitate of strontium nitrate and sodium carbonate go up as the volume of strontium nitrate increase?
Sunday, October 11, 2015 by Anonymous

Chemistry
How many mL of 1.67M sulfuric acid would it take to neutralize 26.6mL of 3.12M sodium hydroxide?
Sunday, October 11, 2015 by Carol

Chemistry
Calculate Delta H for the reaction CH4(g)+NH3(g)-->HCN(g)+3H2(g) given, N2(g)+3H2(g)->2NH3(g) DeltaH=-91.8kj C(s)+2H2(g)->CH3(g) DeltaH=-74.9kj h2(g)+2C(s)+N2(g)->2HCN(g) DeltaH=270.3kj
Sunday, October 11, 2015 by James

Chemistry
The boiling point of pure water in Winter Park, CO ( elev. 9000 ft) is 94 oC. What is the boiling point of a solution containing 11.3 g of glucose (180 g/mol) in 55 mL of water in Winter Park? Kb for water = 0.512°C/m.
Sunday, October 11, 2015 by JPR

Chemistry
determine the vapor pressure lowering at 27 C of a solution of 750g of sucrose, dissolved in 180g of water. The vapor pressure of pure water at 27 C is 26.7 torr. Assume the solution is ideal
Sunday, October 11, 2015 by Anonymous

science
am stuck on the titration on maleic acid. am kindly asking for analytical chemistry by skoog.pdf. this assighnment is killing me. thank you
Sunday, October 11, 2015 by rexina

Chemistry
A 2.00 g impure sample of MgO (molar mass 40.3 grams) was completely dissolved in 50.0 mL of 1.000 M H2SO4. The excess acid was back-titrated with 25.0 mL of 0.800 M NaOH. Calculate the percent purity of the MgO sample. [80.6 %] MgO(s) + H2SO4(aq) MgSO4(aq) + H2O(l)
Sunday, October 11, 2015 by Anonymous

Chemistry
A particular vinegar contains 4.0% CH3COOH by mass. It reacts with sodium carbonate to produce sodium acetate, carbon dioxide, and water. How many grams of carbon dioxide are produced by the reaction of 5.00 mL of this vinegar with an excess of sodium carbonate? The density of...
Saturday, October 10, 2015 by Faith

Chemistry
Three colorless solutions in test tubes, with no labels, are in a test tube rack on the lab bench. Lying beside the test tubes are three labels: potassium iodide, KI, silver nitrate, AgNO3, and sodium sulfide, Na2S. You are to place the labels on the test tubes using only the ...
Saturday, October 10, 2015 by Diana

Chemistry
Write the half reactions and the balanced equation for the galvanic cell Cu(s)| Cu2+(aq)|| Cu+(aq)| Cu(s). What is the smallest possible integer coefficient of Cu2+(aq) in the combined balanced equation? When put together the balanced equation is just Cu + Cu+ = Cu2+ + Cu. So ...
Saturday, October 10, 2015 by Alex

Chemistry
The equation is: CuSO4(s) + Zn(s) -> Cu(s) + ZnSO4(aq) 3.22 g of powdered zinc is added to 200ml of 0.5M copper sulfate solution. What mass of copper is deposited? Hi guys. I am confused about the stoichmetry question. Q: The equation is: CuSO4(s) + Zn(s) -> Cu(s) + ...
Saturday, October 10, 2015 by G

Chemistry
When 22.3 mL of 1.00 M AgNO3 is mixed with 21.7 mL of 1.50 M NaCl, the temperature of the mixture rises for 21.6 degrees C to 29.7 degrees C. The mass of the aqueous mixture is 45.9 grams and its specific heat capacity is 3.94 J/grams degrees C
Saturday, October 10, 2015 by Sarah

chemistry
Write the balanced equation for the reaction of aqueous Pb(ClO3)2 with aqueous NaI. Include phases. What mass of precipitate will form if 1.50 L of highly concentrated Pb(ClO3)2 is mixed with 0.350 L of 0.290 M NaI? Assume the reaction goes to completion.
Saturday, October 10, 2015 by jeff

Chemistry
* From your hint, I arrived at an answer of 3.46 x 10^4 but the answer key says 3.11 x 10^5 Ib. A backyard swimming pool holds 185 cubic yards (yd^3) of water. What is the mass of the water in pounds? DrBob222: 185 yd^3 x (3 ft/yd) x (3 ft/yd) x *3 ft/yd) = ? cubic feet. ...
Saturday, October 10, 2015 by Anonymous

Chemistry
The single proton that forms the nucleus of the hydrogen atom has a radius of approximately 1.0 x 10^-13 cm. The hydrogen atom itself has a radius of approximately 52.9 pm. What fraction of the space within the atom is occupied by the nucleus.
Saturday, October 10, 2015 by Anonymous

Chemistry
A backyard swimming pool holds 185 cubic yards (yd^3) of water. What is the mass of the water in pounds?
Saturday, October 10, 2015 by Anonymous

chemistry
onsider the following reaction between sulfur trioxide and water: SO3(g)+H2O(l)→H2SO4(aq) A chemist allows 61.5 g of SO3 and 11.2 g of H2O to react. When the reaction is finished, the chemist collects 59.3 g of H2SO4.
Friday, October 9, 2015 by luis

chemistry
What is the (H3O+) and the ph of a buffer that consists of 0.25M HNO2 and 0.69M KNO2? (Ka of HNO2 = 7.1 x 10^-4) is this right? pH of acidic buffer pH = pka + log(salt/acid) pka = -log ka = -log(7.1*10^(-4)) = 3.15 = 3.15+log(0.25/0.69) pH = 2.71 [H3O+] = 10^-pH = 10^(-2.71...
Friday, October 9, 2015 by patrick

Chemistry
A sphere of metal has a radius of 5.7 cm and a density of 8.33 g/cm^3. What is the mass of the sphere? Answer in units of g.
Friday, October 9, 2015 by G

Chemistry
What is the mass of water required to fill a circular hot tub 3.6 m in diameter and 1.3 m deep? Answer in units of kg.
Friday, October 9, 2015 by G

Organic Chemistry
Simple Distillation: What is the molar composition of the vapor in equilibrium with a boiling liquid that has a composition of 60% A and 40% B? I know that the vapor should be richer in the lower-boiling substance, which is A in this case. And: If a sample of the vapor has the...
Friday, October 9, 2015 by Sasha

chemistry
What is the mass percent of nitrogen in ammonium carbonate, (NH4)2CO3?
Friday, October 9, 2015 by leona

chemistry
If 3.15 mL of vinegar needs 42.5 mL of 0.115 M NaOH to reach the equivalence point in a titration, how many grams of acetic acid are in a 1.40 qt sample of this vinegar?
Friday, October 9, 2015 by Anonymous

AP Chemistry
Hey guys stuck again! Bromine and chlorine dissolve in carbon tetrachloride and react to form BrCl: Br2 + Cl2--> 2BrCl (in CCl4) Under equilibrium conditions [Br2] = [Cl2] = 0.00430 M and [BrCl] = 0.0114 M. The addition of 0.100 moles of Br2 to exactly one liter of this ...
Friday, October 9, 2015 by Allie

chemistry
If the charge-to-mass ratio of a proton is 9.58 × 107 coulomb/kilogram and the charge is 1.60 × 10-19 coulomb, what is the mass of the proton?
Friday, October 9, 2015 by annonomus

Engineering Chemistry
One reaction that destroys O3 molecules in the stratosphere is NO + O3 → NO2 + O2 When this reaction was studied in the laboratory, it was found to be first order with respect to both NO and O3, with a rate constant of 1.9 x 104 L mol-1 s-1. If [NO] =1.2 x 10-5 mole L-1 ...
Friday, October 9, 2015 by Michelle Zuke

AP Chemistry
Hey guys! Stuck on another one: The reaction 2N2O(g) 2N2(g) + O2(g) has Kc = 3.5 × 10-18 at a particular temperature. If 0.20 mol of N2O is placed in a 1.00 liter container, what will be the N2 concentration when equilibrium is reached? 1. 4.4 × 10-9 mol/liter 4. 3...
Thursday, October 8, 2015 by Allie

Chemistry RUSH, Please
1) How many grams of CH4 (MM = 16.043) are needed to react with 50.0g of CL2 (MM=70.91)? 2) What is the molarity of a solution prepared by dissolving 20.0 g of methanol, CH3OH, oara sufficient water to prepare 500 mL of solution? Show calculations
Thursday, October 8, 2015 by Maria

AP Chemistry
Hey guys! Stuck on some problems: 1)Consider the following chemical reaction between gases: 2N2O(g) + O2(g)->4NO(g) + heat The amount of O2 at equilibrium will be decreased by: 1. Adding more NO(g). 2. Increasing the pressure by decreasing the volume. 3. Removing N2O. 4. ...
Thursday, October 8, 2015 by Allie

chemistry
Nitrobenzene, C6H5NO2, is prepared from benzene, C6H6, and nitric acid, HNO3. The other product of the reaction is water. When 22.4 g of benzene is reacted with an excess of nitric acid, 31.6 g of nitrobenzene is produced. What is the percent yield for this reaction?
Thursday, October 8, 2015 by shannon

chemistry
In the manufacture of iron, carbon monoxide reduces iron oxide. Why isn't hydrogen used?
Thursday, October 8, 2015 by Clive

chemistry (Organic)
According to the two reactions below; 1-chloro-2,2-dimethylbatune + (warm NaOH 3)) 1-chloro-2-methylpropane + (cold dil.NaOH) 1) identify whether the reactions are Nucleophilic Substitutions (SN) or Elimination (E) reaction. 2) Complete the reaction mechanismin each and name ...
Thursday, October 8, 2015 by johnny

chemistry
Describe how one would prepare these solutions in the laboratory, using weights reagents and volumes of solutions: -500 mL of .100M K2Cr)4 stock solution from pure K2CrO4(s) -10mL of .0025M K2CrO4(aq) from .100M K2CrO4(aq) -What would the concentrations of FeSO4 and KCL be if ...
Thursday, October 8, 2015 by Lay

general chemistry
a solution of sulfuric acid was titrated with sodium hydroxide. if you took 23.7 mL of .025 M NaOH to reach the endpoint with a 5.0 mL sample of the acid what was its concentration?
Thursday, October 8, 2015 by Lay

Chemistry
how many grams of NaOH do you need to prepare a 3.00 x 10^2 mL stock solution of 2.00 M NaOH
Wednesday, October 7, 2015 by Alexander

Chemistry
how can two clear solutions mix and produce a cloudy precipitate- what is going on? Is this good or can I add something else? When two clear solutions mix together and produce a cloudy precipitate, it means that the compound that was created, was insoluble, causing a full ...
Wednesday, October 7, 2015 by Finn

Chemistry
4.Report your answer in correct significant figures. A.1.32*10^4cm+2.1*10^2
Wednesday, October 7, 2015 by anonymous

chemistry (inorganic) reflection planes
how many planes of reflection (sigma v) does the letter "H" have? an infinite amount? this is for an intro to group theory / symmetry operations.
Wednesday, October 7, 2015 by paul

Chemistry
How do halogens (Cl2, Br2, I2) react with halides (Cl-, Br-, I-)? Can we explain this reactivity?
Wednesday, October 7, 2015 by Anonymous

Chemistry
What is the relationship between the relative reactivities of the halogens when compared to the relative reactivity of the halides?
Wednesday, October 7, 2015 by Anonymous

Chemistry
A 76.00-pound flask of mercury costs $150.00. The density of mercury is 13.534 g/cm3. a) Find the price of one cubic inch of mercury by calculating the following intermediate values. Following intermediate values include grams, cubic centimeters and cubic inch. I have no idea ...
Wednesday, October 7, 2015 by Jenny

chemistry
Find the volume of a 2.5 M solution of sulfuric acid required to prepare 300.0 mL of 0.1 N solution of sulfuric acid
Wednesday, October 7, 2015 by Cole

chemistry
How many moles of platinum would be in 10.0 g of this metal?
Wednesday, October 7, 2015 by Lauren

Chemistry
How do magnesium atoms form ions? What about oxygen atoms?
Wednesday, October 7, 2015 by Trinity

chemistry
A graduated cylinder contains 17.0 mL of water. What is the new water level after 31.6 g of silver metal with a density of 10.5 g/mL is submerged in the water
Wednesday, October 7, 2015 by timmy

Chemistry
A Stock solution has a total volume of 1.5l. It is diluted by removing 10 ml of the stock and adding 90 ml of water. the diluted solution has a concentration of the solute of 40mg/l a, what is the concentration of the solute in the stock solution? b, How much solute is present...
Tuesday, October 6, 2015 by Tony Ayo

CHEMISTRY
is this right? 5. After heating the crucible is set on the lab bench where it is contaminated with the cleaning oil used to clean the lab bench but before its mass is measured. The analysis continues where the mass of the anhydrous salt is determined. While heating, the ...
Tuesday, October 6, 2015 by Diana

CHEMISTRY
I also need help in this please: Suppose the original sample is unknowingly contaminated with a second anhydrous salt. Will the reported percent water in the hydrated salt be too high, too low, or unaffected by its presence? Explain. is it low? if so, can you explain in some ...
Tuesday, October 6, 2015 by Diana

Chemistry
2C2H6(g) + 7O2(g) → 4CO2(g) + 6H2O(g) In the equation, if 14 L of ethane (C2H6) and 14 L of oxygen (O2) combined and burned to completion, which gas will be leftover after the reaction, and what is the volume of that gas remaining?
Tuesday, October 6, 2015 by Giselle Meza

Chemistry
How many moles of chloride ions are in 100mL of a 0.3molar solution of AlCl3? #moles Cl =(.3M AlCl3)(.1L)(105g/mol / 132g/m0l)
Tuesday, October 6, 2015 by Kim

chemistry
In a chemistry experiment, a student measures the density of iridium (Ir) metal as 21.52 g/cm3. The actual density of Ir metal is 22.65 g/cm3. What is the percent error of the student's measurement?
Tuesday, October 6, 2015 by SAM

Chemistry
A sample that is 63.9 % chloride by mass is dissolved in water and treated with an excess of AgNO3. If the mass of the AgCl precipitate is 1.045g, what was the mass of the original sample?
Tuesday, October 6, 2015 by Ashley

Chemistry
. Show a chemical reaction by which hardness is added to water that also explains the formation of caves in limestone formations?
Tuesday, October 6, 2015 by Lee

Chemistry
30cm^3 of a mixture of methane and ethyne require 70cm^3 of oxygen for complete combustion. Calculate the composition of the mixture.
Tuesday, October 6, 2015 by Khadeejah

Himma International College Minna
Chemistry: 30cm^3 of a mixture of methane and ethyne require 70cm^3 of oxygen for complete combustion. Calculate the composition of the mixture
Tuesday, October 6, 2015 by Khadeejah

Chemistry
Could someone please walk me through how to solve this problem: A sample that is 63.9 % chloride by mass is dissolved in water and treated with an excess of AgNO3. If the mass of the AgCl precipitate is 1.045g, what was the mass of the original sample?
Tuesday, October 6, 2015 by Ashley

Chemistry
A 453 mL solution has a chloride concentration of 0.0253 M. This solution was prepared by adding solid FeCl3 to water. How many grams of FeCl3 are required?
Monday, October 5, 2015 by Kim

chemistry
Find the equilibrium constant for the reaction Cr(s) + Zn2+(aq) → Cr2+(aq) + Zn(s) if the standard cell emf is −0.76 V at the cathode and −0.91 V at the anode. R T F = 0.025693 V
Monday, October 5, 2015 by jack hoff

Chemistry
A 0.1592g sample of a hydrocarbon upon combustion analysis produces 0.5008g CO2. Its molar mass is found in another experiment to be 70g mol. Determine the empirical formula, and its molecular formula. I completely messed up this question, and I don't know where I wen'...
Monday, October 5, 2015 by Sarah

chemistry
A student is asked to standardize a solution of barium hydroxide. He weighs out 0.986 g potassium hydrogen phthalate (KHC8H4O4, treat this as a monoprotic acid). It requires 27.8 mL of barium hydroxide to reach the endpoint. A. What is the molarity of the barium hydroxide ...
Monday, October 5, 2015 by charlotte

Organic Chemistry
Describe why an unsubstituted C6 ring doesnt have any steric strain, torsional strain or angle strain.
Monday, October 5, 2015 by A

Chemistry
15.00mL sample of a solution of H2SO4 of unknown concentration was titrated with 0.3200 N NaOH. The titration required 21.30mL of the base. What was the normality of the acid solution? what was the molarity of the acid solution?
Monday, October 5, 2015 by Mark

Chemistry
I need a balanced chemical equation for the titration of potassium iodate (KIO3^2-) and sodium thiosulfate (Na2S2O3^2-). This is what I have, but I was wondering if I should cancel the spectator ions: Na2S2O3 (aq) + 2KIO3 (aq) --> K2S2O3 (aq) + 2NaIO3(aq)
Monday, October 5, 2015 by Ronnie

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Homework Help: Science