Wednesday
May 4, 2016

Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

Chemistry
How much energy will be liberated upon the combustion of 12.5 grams of ethene? C2H4(g) + 3O2(g) ----> 2CO2(g) + 2H2O(g) Delta H = -1387.4 kj
Monday, April 4, 2016 by Rose

Chemistry
Number of Moles of AgNO3 when 0.25 grams of NaCl react with AgNO3
Monday, April 4, 2016 by melanie

Chemistry-Dr.Bob222
Determine [OH-] of a solution that is 0.135 M in CO3^2-. I got 0.00532.
Monday, April 4, 2016 by Nevaeh

Chemistry
Calculate the concentrations of Cd ⁺ ², [Cd (CN)₄-²] and CN at equilibrium when they dissolve mole of 0.42 Cd (in the ₃)²⁺ 2.50 M. Given: Kf = 7, 1 x 10 ^16
Monday, April 4, 2016 by Kelly

Chemistry
5.88 moles of nitrogen and 16.2 moles of oxygen are mixed until the equilibrium is established 11.28 moles of nitric acid are formed calculate the value of equilibrium constant
Monday, April 4, 2016 by Mohammad

organic chemistry
In an eudiometer 20cm^3 of a gaseous hydrocarbon A is mixed with 150 cm^3 of oxygen. The combustion of A is initiated by an electric spark. After cooling and condensing the vapor the volume of the gaseous mixture is 110cm^3 of which 80cm^3 causes turbidity of limewater. The ...
Monday, April 4, 2016 by angy

organic chemistry
In an eudiometer 20cm^3 of a gaseous hydrocarbon A is mixed with 150 cm^3 of oxygen. The combustion of A is initiated by an electric spark. After cooling and condensing the vapor the volume of the gaseous mixture is 110cm^3 of which 80cm^3 causes turbidity of limewater. The ...
Monday, April 4, 2016 by angy

Chemistry
Calculate the Ksp for silver sulfate if the solubility of Ag2SO4 in pure water is 4.5 g/L. Ag2SO4(s) <--> 2Ag^+(aq) + SO4^2-(aq)
Monday, April 4, 2016 by Ayaka

Chemistry- Dr.Bob222
Ammonium hydroxide is commonly advertised as an ingredient in some window cleaners. Rank the following in order of decreasing concentrations in these solutions: NH4OH, NH4+, OH-, NH3. Explain your reasoning. (Note that kb for ammonia = 1.8 x 10^-5. So does an unionized ion ...
Sunday, April 3, 2016 by Nevaeh

Chemistry
What is the difference between an Arrhenius acid/base, a Brønstead Lowry a/b and a Lewis a/b?
Sunday, April 3, 2016 by Nurah

Chemistry
Boron trifluoride (BF3) has properties ordinarily associated with acids. According to what acid base theory or theories is it considered an acid? Is it an Arrhenius, Brønstead, Or Lewis Definition? Or is it all? Thank you very much.
Sunday, April 3, 2016 by Nurah

Chemistry
You have 1.0 liter of .45 M HCLO (aq). At 25 degrees Celsius, Ka= 3.5x10^8 for this acid. Calculate the pH of .45 M HCLO and the concentration of CLO- at equilibrium. Thank you very much for any amount of help you are willing to give me.
Sunday, April 3, 2016 by Nurah

chemistry
to complex ( K2[Cu(C2O4)2]H2O, add 1 com of dil. H2SO4. Add KI; then add 1-2cm3 choloform and shake gently. what are the observations.
Sunday, April 3, 2016 by jamie

Chemistry - Dr.Bob 222
The pH scale ranges from 0 to 14. What is the range of the hydronium ion concentration covered by this scale?
Sunday, April 3, 2016 by Nevaeh

Chemistry
For the following chemical reaction HCN(aq)+KOH(aq)--->H2O(l)+KCN(aq) Write the net ionic equation, including the phases.
Sunday, April 3, 2016 by Ann

Chemistry
I need help with this question Which would have a higher boiling point? a.1.0 M KNO3 b.1.5 M KNO3 c.0.75M KNO3 d.2.0M KNO3
Sunday, April 3, 2016 by rebekah

Chemistry
I need help with this question. If the solubility of a gas in water is 6.0 g/L when the pressure of the gas above the water is 2.0 atm, what is the pressure of the gas above the water when the solubility of the gas is 3.0 g/L?
Sunday, April 3, 2016 by rebekah

chemistry
When 23g of C8H18 is combusted at STP, how many liters of carbon dioxide is produced?
Sunday, April 3, 2016 by Justin

Chemistry
A saturated aqueous solution of calcium hydroxide, Ca(OH)2, is approximately 0.13% calcium hydroxide, by mass, and has a density of 1.02 g/mL. What is the pH of such a solution?
Sunday, April 3, 2016 by Ayaka

Chemistry
Is the formation of C2H2 endothermic or exothermic?
Sunday, April 3, 2016 by Angie

Chemistry
I need help with this question, I don't know how to set up the formula to work it out? Calculate the dissociation constant of a weak monoprotic acid if a 0.08 M solution of this acid gives a hydrogen-ion concentration of 0.0001 M?
Sunday, April 3, 2016 by rebekah

Chemistry
You are completing tests using a weather balloon and want to check the temperature at 3000 meters into the air. You check if the balloon will not burst before it gets to that altitude. You will need to perform a few calculations. The manufacturer of the balloon guarantees it ...
Sunday, April 3, 2016 by Anonymous

Chemistry
If 210 mL of isopropyl alcohol is diluted with water to a total volume of 300 mL, what is the percent by volume of isopropyl alcohol in the solution? Would it be 70%??
Sunday, April 3, 2016 by rebekah

chemistry
How many grams of NaC2H3O2 are needed to prepare 350. mL of a 2.75 M solution? i got 79.0 ??
Sunday, April 3, 2016 by Boberto

Chemistry
Describe how you would make a 125 mL of 0.025 M solution of potassium dichromate?
Sunday, April 3, 2016 by Alicia

Chemistry
I need help with this question, I don't know how to do it. If 210 mL of isopropyl alcohol is diluted with water to a total volume of 300 mL, what is the percent by volume of isopropyl alcohol in the solution?
Sunday, April 3, 2016 by rebekah

Chemistry
calculate the amount of heat released, in joules, in converting 75.0 g of steam at 115 degrees of Celsius to steam at 110 degrees Celcius
Sunday, April 3, 2016 by Brandi

college general chemistry 2
a chemist titrates 70 ml of .7889M HClO solution with .6221M KOH. calculate pH at equivalence. pKa of HClO is 7.50 I am getting pH of 17.72 Is that right?
Sunday, April 3, 2016 by osp

Chemistry
320.0 gallons of 15 M nitric acid were added to a lake. The initial pH p the lake was 6.30 and the final pH was 4.60. What is the volume of the lake?
Sunday, April 3, 2016 by Meg

chemistry
Which one has more hydrogen bonding- ethanol or methanol
Sunday, April 3, 2016 by Anonymous

chemistry
suppose as student returned some unused lead nitrate to the container marked sodium nitrate. what could the student do to get all the lead ions out from the sodium nitrate?
Saturday, April 2, 2016 by mira

Chemistry
Water is a great solvent for ionic compounds because of its ??
Saturday, April 2, 2016 by Boberto

Chemistry
I have a gr 10 chemistry unit test coming up can someone please refresh my mind on this unit? and tell me what things i should practice for the test? Tyy
Saturday, April 2, 2016 by Science

chemistry
if I have 3 tablespoons of sugar (15 grams) and dissolve it in 1 cup (~237 mL) and take out 30 mL what is the molarity in the 30 mL?
Saturday, April 2, 2016 by Anonymous

Chemistry
2- Gases A2 and B2 react according to the equation: A2 + B2 → AxBy . If equimolar ( not necessarily stoichiometrically equivalent) quantities are placed in a reaction vessel with a massless, frictionless piston and allowed to react to completion. The density of the gas ...
Saturday, April 2, 2016 by Ian

chemistry
if I have 3 tablespoons of sugar (15 grams) and dissolve it in 1 cup (~237 mL) and take out 30 mL what is the molarity in the 30 mL?
Saturday, April 2, 2016 by Anonymous

Chemistry
A sample of 0, 3220g of an ionic compound containing bromide ions (Br-) is dissolved in water and treated with excess of AgNO3. If the mass of the precipitate of AgBr formed is 0, 6964g, answer: a) what percentage of bromine in molar mass? b) Give the mass of bromine in the ...
Saturday, April 2, 2016 by Elizabeth

chemistry stoichiometry
can someone explain the stoichiometry going on here... so the questions is: A solution containing 0.20g of calcium salt is passed thru a column containing the hydrogen form of a strong acid cation exchange resin. The resulting solution is neutralized with 35 mL of .1 M NaOH. ...
Saturday, April 2, 2016 by Anonymous

Chemistry
85.0 mL of 1.50 mol/L ammonium chloride solution is added to 250 mL of water. Calculate the molar concentration of the final solution The answer on the sheet says 0.381 mol/L but I keep getting 0.51
Saturday, April 2, 2016 by AmbiguousCase

Chemistry
1. A lab tech needs 1.00 L of 0.125 mol/L sulfuric acid solution for a quantitative analysis experiment. A commercial 5.00 mol/L sulfuric acid solution is available from a chemical supply company. Write out what steps he/she would follow to prepare the needed solution. Include...
Saturday, April 2, 2016 by AlphaPrimes

analytical chemistry
0.100 M NaOH (in the burette) is titrated with 25.0 mL 0.120 M CH3COOH (pKa = 4.75) in a conical flask. Determine the pH of the solution in the flask after 10 mL of the NaOH has been added.
Saturday, April 2, 2016 by TaeRa

Chemistry
A sample of 0, 3220g of an ionic compound containing bromide ions (Br-) is dissolved in water and treated with excess of AgNO3. If the mass of the precipitate of AgBr formed is 0, 6964g, answer: a) what percentage of bromine in molar mass? b) Give the mass of bromine in the ...
Saturday, April 2, 2016 by Elizabeth

Chemistry
How much NACl do i need to dissolve in grams to make 0.9%solution of 0.25l saline
Friday, April 1, 2016 by Kasey

chemistry
Net Ionic Reaction and molecular Equations of Ca3(PO4)2
Friday, April 1, 2016 by Anonymous

Chemistry
An impure sample of (COOH)2 · 2 H2O that has a mass of 2.9 g was dissolved in water and titrated with standard NaOH solution. The titration required 32.4 mL of 0.144 mo- lar NaOH solution. Calculate the percent (COOH)2 · 2 H2O in the sample.
Friday, April 1, 2016 by Bella

Chemistry
A 26.8 mL sample of a solution of RbOH is neutralized by 15.71 mL of a 1.918 M solution of HBr. What is the molarity of the RbOH solution?
Friday, April 1, 2016 by Sarah

chemistry
A certain elementary gas is triatomic and has vapour density 48 . The atomic mass of the gas is (a) 48 (b) 96 (c) 32 (d) 16 ..
Friday, April 1, 2016 by jay

Chemistry
10.5g of zinc trioxocarbonate(iv) were heated very stronglu to a constant mass and the residue treated with excess Hcl.calculate the mass of zinc chloride
Friday, April 1, 2016 by Peace

Chemistry
10.5g of zinc was heated to a constant mass and the residue treated with excess Hcl: ZnCo3+Hcl-----ZnCl2+Co2+H2O. Calculate the mass of zinc chloride that would be obtained
Friday, April 1, 2016 by Peace

chemistry
What is the oxidation number of chlorine in Al(ClO4)3? I don't understand this question, can someone help? Thank you!
Friday, April 1, 2016 by louren

Chemistry
Why is methyl orange not suitable indicator for h2c2o4 and naoh
Friday, April 1, 2016 by Ifunanya

Chemistry
The rock in a particular iron ore deposit contains 84 % Fe2O3 by mass. How many kilograms of the rock must be processed to obtain 1100 kg of iron?
Thursday, March 31, 2016 by Aria

Chemistry
What is the pH of a solution made by mixing 1.40 mL of 0.0043 molar Sr(OH)2 with 8.90 mL of 0.0029 molar Sr(OH)2 solution?
Thursday, March 31, 2016 by Kelly

Chemistry
Suppose a saturated solution of barium fluoride contains 1.5 x 10 ^ -2 M of F-. What is the Ksp of BaF2. I know that the balanced equation of this reaction is: BaF2 (s) --> Ba2+ (aq) + 2F- (aq) There is a 1:1 ratio between BaF2 and Ba2+ and there is a 1:2 ration between ...
Thursday, March 31, 2016 by Grace

chemistry
Given the balanced equation: 2 Al + Fe2O3 → Al2O3 + 2 Fe how many grams of Al2O3 will be produced if 68.1 g Al reacts with 112 g Fe2O3?
Thursday, March 31, 2016 by Winter

chemistry
Given overall reaction: P4 + 10Cl2 ---> 4PCl5 Delta H for the reaction = ? PCl5 -----> PCl3 + Cl2 Delta H = +157 kJ P4 + 6Cl2 ----> 4PCl3 Delta H = -1207 kJ Calculate the Delta H for the overall reaction.
Thursday, March 31, 2016 by John

Chemistry
. Okay 2HgO turns into 2hg + O2. What mass of Co2 can be produced from 25.0g of Fe3O4 ?
Thursday, March 31, 2016 by Maxwell

Chemistry
How do I make 500ml of a 0.3% chlorine dioxide solution from 6.4% tablets?
Thursday, March 31, 2016 by Pam

CHEMISTRY
How would you prepare 750 ml of a 10 fold dilution of a 17 M solution of acetic acid? How would you prepare 200 ml of a 20 fold dilution of a 17 M solution of acetic acid? please explain and show me the calculations.
Thursday, March 31, 2016 by rockey

Chemistry
How do I make a 500ml amount of a 0.3% aqueous solution of chlorine dioxide
Thursday, March 31, 2016 by Pam

Chemistry
What mass of copper(ii) sulphate(GFM=159.5) is required to make 400cm3 of 0.5mol/l solution
Thursday, March 31, 2016 by Callum

chemistry
If 5.40 kcal of heat is added to 1.00 kg of water at 100⁰C, how much steam at 100⁰C is produced? Show all calculations leading to an answer. I can't figure this one out, can someone help me? Thank you!
Thursday, March 31, 2016 by louren

chemistry
You have two sealed jars of water at the same temperature. In the first jar there is a large amount of water. In the second jar there is a small amount of water. Using 3 -4 sentences explain how the vapor pressure of water in the first jar compares with the vapor pressure of ...
Thursday, March 31, 2016 by louren

chemistry
I don't understand the difference between endothermic and exothermic?
Thursday, March 31, 2016 by Carly

Chemistry
A sample of propane, C3H8, contains 10.0 moles of carbon atoms. How many total moles of atoms does the sample contain? Express the total number of moles of carbon and hydrogen numerically.
Wednesday, March 30, 2016 by Aria

chemistry
A gas occupies 5.65 L at 808 torr and 17◦C. What volume will it fill if the pressure is changed to 730 torr and the temperature is raised to 51◦C?
Wednesday, March 30, 2016 by emily

Chemistry
If the total number of electrons in the ion [M (H2O) 4] +2 is equal to 50 Whish is the atomic number of M?
Wednesday, March 30, 2016 by Kassia

Chemistry
Show how you would calculate the % yield of hydrogen if 40.0 grams of magnesium react with an excess of nitric acid producing 1.70 grams of hydrogen gas. Mg + 2 HNO3 ---> Mg(NO3)2 + H2
Wednesday, March 30, 2016 by Elizabeth

Chemistry
3.2 grams of calcium chloride reacts with 3.55 grams of sodium sulfate producing calcium sulfate + sodium chloride. Which is the reactant in excess and the excess mass? Cacl2 + Na2SO4 = CaSO4 + NaCl
Wednesday, March 30, 2016 by Kennia

Chemistry
Determine the specific mass of fluorine (F2) in g/cm³ in 20°C and 188 torr
Wednesday, March 30, 2016 by Jimmy B

chemistry concentrations
if i calculated a dilution concentration from excel to be 0.171 ppm, how do i calculate the concentration of the analyte in 64 fl oz bottle? So we pulled 10 mL out, and diluted it to 40 mL...is this right, 0.171 ppm / (10 mL/40mL) = concentration in 1 bottle?
Wednesday, March 30, 2016 by Anonymous

Chemistry
Small amounts of chlorine gas can be gener- ated in the laboratory from the reaction of manganese(IV) oxide with hydrochloric acid: 4 HCl(aq) + MnO2(s) → 2 H2O(l) + MnCl2(s) + Cl2(g). What mass of Cl2 can be produced from 41.8 g of MnO2 with an excess of HCl(aq)?
Wednesday, March 30, 2016 by Will

Chemistry
When 0.07 moles of ammonium sulfate ((NH4)2SO4) are dissolved in enough water to make 254 milliliters of solution, how many ammonium ions are present?
Wednesday, March 30, 2016 by Eva

Chemistry
How do you complete the following by writing products? #1.Ca(OH)2+MgCl
Wednesday, March 30, 2016 by Tas

chemistry
calculate the solubility of PbI2 in 0.0123M CaI2. Ksp=6.81x10^-9
Wednesday, March 30, 2016 by benji

Chemistry
How many moles are in 2.3 grams of oxygen gas.
Wednesday, March 30, 2016 by Jake

chemistry
why does the solubility of most solid substances in liquid solvents increase in temperature whereas gases reduce
Wednesday, March 30, 2016 by anonymous

chemistry
explain briefly why CuSo4 is more soluble in water than in organic solvent
Wednesday, March 30, 2016 by zainab

Chemistry
What is the pH of the solution when 50.00 mL of 0.250 M HNO3, nitric acid, has been treated with 25.00 mL of 0.400 M NaOH? Below is the work I performed, however, my professor deemed the [H3O] as incorrect. Where did I go wrong? [NaOH] = .025 L x 0.400 M = .010 mol [HNO3] = ....
Wednesday, March 30, 2016 by Alex

chemistry
what is the charge balance equation for acetic acid?
Wednesday, March 30, 2016 by lia

chemistry
For the following reaction at equilibrium, which change would shift the position of equilibrium toward forming more products? (Circle your answer(s) as there may be more than one.) 2NOBr(g) 2NO(g) + Br2(g), ∆Hºrxn = +30 kJ/mol A) Decrease the total pressure by ...
Wednesday, March 30, 2016 by maria

Chemistry
Write the balanced equation when 9 grams of water undergo electrolysis and calculate the amount of oxygen gas liberated?
Tuesday, March 29, 2016 by Ravalipriya

Chemistry
@DrBob222 I got the last question that I posted wrong and I solved it the same way. Could you show me the answer and how you got it? My test is Friday and this is a practice problem. Suppose that 30 mL of 0.5 M CsOH and 55 mL of 0.1 M NaHS are mixed. What is the K for the ...
Tuesday, March 29, 2016 by Sarah

Chemistry
A single dose of a certain antacid contains 250. mg of Mg(OH)2 and 300. mg of CaCO3. How many mmol of H+ can be neutralized by one dose of this antacid? Do not include units in your answer
Tuesday, March 29, 2016 by Chris

Chemistry
Suppose that 30 mL of 0.5 M CsOH and 55 mL of 0.1 M NaHS are mixed. What is the K for the dominant equilibrium in terms of Ka's, Kb's, Kw etc.? Ka of HS- 1/Ka of HS- Kb of OH- 1/Kb of OH- Kb of S-2 1/Kb of S-2 Kw 1/Kw There is no reaction.
Tuesday, March 29, 2016 by Sarah

Chemistry
A chemist dissolves 0.096 g of CuSO4 · 5 H2O in water and dilutes the solution to the mark in a 500-mL volumetric flask. A 10.8-mL sample of this solution is then transferred to a second 500-mL volumetric flask and diluted. What is the molarity of CuSO4 in the second ...
Tuesday, March 29, 2016 by Eva

Chemistry
A chemist dissolves 0.096 g of CuSO4 · 5 H2O in water and dilutes the solution to the mark in a 500-mL volumetric flask. A 10.8-mL sample of this solution is then transferred to a second 500-mL volumetric flask and diluted. What is the molarity of CuSO4 in the second ...
Tuesday, March 29, 2016 by Eva

Chemistry
Suppose that 85 mL of 0.4 M NaF and 50 mL of 0.4 M HCl are mixed. What is the K for the dominant equilibrium in terms of Ka's, Kb's, Kw etc.? Ka of HCl 1/Ka of HCl Ka of HF 1/Ka of HF Kb of F- 1/Kb of F- Kb of Cl- 1/Kb of Cl- Kw 1/Kw There is no reaction.
Tuesday, March 29, 2016 by Sarah

Chemistry
85.0 mL of 1.50 mol/L ammonium chloride solution is added to 250 mL of water. Calculate the molar concentration of the final solution. Using the formula C(Concentration)=n(moles)/v(Volume measured in litres.) How am I supposed to solve this question given two volumes?
Tuesday, March 29, 2016 by AlphaPrimes

Chemistry
What size container do you need to hold 0.0459 mol of N2 gas at stp
Tuesday, March 29, 2016 by Jimmy B

Chemistry
What is the OH- concentration of a solution whose pH is 12.40?
Tuesday, March 29, 2016 by Trinity

Chemistry
How many moles of oxygen (O2) are required to completely react with 27.4 mol of H2?
Tuesday, March 29, 2016 by Dylan

Chemistry
Which element has an ion that is smaller than an ion of calcium?
Tuesday, March 29, 2016 by Lisa

chemistry
A 190 mL sample of 0.293 M NaCH3CO2(aq) is diluted to 750 mL. What is the concentration of the acetic acid at equilibrium? Ka =1.8×10−5.
Tuesday, March 29, 2016 by Anonymous

AP Chemistry
A 190 mL sample of 0.293 M NaCH3CO2(aq) is diluted to 750 mL. What is the concentration of the acetic acid at equilibrium? Ka =1.8×10−5. Answer in units of mol/L.
Tuesday, March 29, 2016 by Samantha

chemistry
Experimental Design: From the work you have done this semester, choose a topic and design an experiment you would be able to perform. In your design (1) state your hypothesis, (2) identify your dependent and (3) independent variables, (4) your control conditions and (5) ...
Tuesday, March 29, 2016 by louren

chemistry
Magnesium nitride is formed in the reaction of magnesium metal with nitrogen gas in this reaction: 3 Mg(s) + N2(g) --> Mg3N2(s) How many grams of product are formed from 2.0 mol of N2 (g) and 8.0 mol of Mg(s)? i havent been able to figure this one out, can someone help me?
Tuesday, March 29, 2016 by louren

Chemistry- Dr.Bob222
Which if the folowin species is not amphoteric? a) H2SO4 b) H2PO4- c) HPO4 2- d) HSO4- e) H2O
Monday, March 28, 2016 by Nevaeh

Chemistry
We have an aqueous solution that contains 22% (by mass) of a hypothetical solute Z. The formula weight of the solute Z is 215 g/mol. The density of the solution is observed to be 1.1 g/mL. What is the molarity of Z in this solution?
Monday, March 28, 2016 by El

Chemistry
I've run into some difficulty with my chemistry homework. We went over this practise question in class today as an example. However, I wasn't able to fully grasp how to work it out. "How many grams of nitrogen form when 34.6 grams of nitrogen dioxide decomposes ...
Monday, March 28, 2016 by Kara

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Homework Help: Science