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March 23, 2017

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Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

chemistry
A process is carried out at constant pressure. Given that ΔE is positive and ΔH is negative, Select one: A. the system absorbs heat and contracts during the process. B. the system absorbs heat and expands during the process. C. the system loses heat and contracts during the ...
Monday, November 14, 2016 by betty boop

chemistry
Zinc reacts with sulphur to form zinc sulphuric 16.2g.Sample of zinc is reacted with log of sulphur(Zn=65,S=32,o=16) A)Write a chemical reaction for the reaction b)Calculate the number of moles of zinc atoms that reacted. c)Number of moles of sulphur atoms that reacted
Monday, November 14, 2016 by Anonymous

Chemistry
What problems might arise if the anesthesiologist did not know the patient's higher body temperature?
Monday, November 14, 2016 by Tayler

chemistry
Calculate the final temperature that results from mixing 245 grams of cobalt, specific heat 0.446 J/g0C, at 1420C with 106 grams of water at 24.80C.
Monday, November 14, 2016 by cao

Chemistry
Use two concentration tables to calculate the concentrations of the species present in a 0.0400 M solution of CsBrO. a.[HBrO] b.[BrO-] = 0.0400M c. [H3O+] d.[OH-] hi. how would I attempt this problem. can you walk me through it or give me a hint.
Monday, November 14, 2016 by J

chemistry
stoichiometry problem Fe2O3+HCl=H2O+FeCl3 If 42.2 grams of iron(III) Oxide react with HCl how many gramd of iron(III)chloride should be produced
Sunday, November 13, 2016 by yvette

Chemistry
A student determined the calorimeter constant of the calorimeter. The student added 50.00 mL of cold water to 50.00 mK of heated , distilled water in a styrofoam cup. The initial temp of the cold water was 21,00C and the hot water, 29.15C. The maximum temp pf the mixture was ...
Sunday, November 13, 2016 by Yari

Chemistry
For a 0.47 M solution of LiClO compute the pH. Hi. I am confused about this question. I calculated the pH...but my answer is wrong. what am I doing wrong??? pH=-log(0.47) pH=0.33
Sunday, November 13, 2016 by J

Chemistry (molarity) (sorta an emergency)
I'm doing a titration lab and writing a lab report where I'm sort of stuck on how exactly to find the concentration of HCl. These are the following info I have from the lab, Equation: HCl(aq)+NaOH(aq)-> H2O(l)+NaCl(aq) -Calculated molarity of NaOH solution is .103M -Volume ...
Sunday, November 13, 2016 by Ray

Chemistry
Normal glucose levels in the blood are from 70 to 110 mg glucose per 100mL of blood. If the level falls to low, there can be brain damage. If a person has a glucose level of 92 mg/ 100mL, what is the total mass of glucose in grams in 5.10 L of blood?
Sunday, November 13, 2016 by Joe

Chemistry
When you try to leave your room you learn that the only door out is locked. Assuming there is no air flow into the room (air tight with no ventilation system) how long can you survive in the room (5 meters long, 5 meters wide, 5 meters high) -Human tidal volume (volume of air ...
Sunday, November 13, 2016 by Sarah

Chemistry
Elemental analysis of a compound, once used as a pesticide, was found to be 74.2% carbon, 8.64% hydrogen, and 17.2% nitrogen. What is the empirical formula of this compound?
Sunday, November 13, 2016 by Kim

Chemistry
November's birthstone is citrine, a yellow member of the quartz family. It is primarily silicon dioxide, but small amounts of iron(III) ions give it its yellow color. A high quality citrine containing about 0.040 moles of SiO2 costs around $225. If this stone were pure SiO2, ...
Sunday, November 13, 2016 by Kim

Chemistry
There are about 1 x 10^5 chemical reactions per second in each of the 10 billion nerve cells in the brain. How many chemical reactions take place in a day in a single nerve cell?
Sunday, November 13, 2016 by Kim

Chemistry
Compare the energy needed to raise the temperature of 1kg of water from 20°C to 100°C and the energy needed to boil 1kg of water at 100°C? I turned 1kg to 1000g water is 4.18J/g°C and subtracted 20°C then i get confused as what to do next to
Sunday, November 13, 2016 by Janiya

Chemistry
How many electrons in an atom could have these sets of quantum numbers? n=2 n=5, l=3 n=6, l=1, ml=-1
Sunday, November 13, 2016 by Jen

chemistry limiting reagent
if i have a 1:1 mole ratio as with this reaction: NaOH + HCl --> NaCl + H20 and i use same volumes (50mL) and same Molaritys (1.00M) then there is no limiting reactant correct??
Sunday, November 13, 2016 by amy

chemistry
Is this balanced properly 2H2O2----> 2H2O +O2 Thank you for the reactions of zinc and acetic acid. REAL QUESTION, if I was to rub all the copper off of a new penny down to the zinc, what would be the appearance of the zinc if I left it in vinegar (acetic acid ) for 30min. I...
Sunday, November 13, 2016 by lulu

chemistry
Assume that it is necessary to determine the [FE^3+ in a solution that may be 0.0001 to 0.0005 M range . Outline the spectrophotometric method that would accurately give the required data. Be spectific about the solutions that you would use. I know I have to work up a ...
Sunday, November 13, 2016 by jxv

chemistry
Dr Bob, Sorry about this penny thing, but if I was to put pure zinc into acetic acid, what would happen to the zinc?
Sunday, November 13, 2016 by lulu

Chemistry
A chemist takes a 647 gram sample of this hydrate. She removes all the water possible from the sample and collects it. To this water, she adds 7.6 grams of lead(II) nitrate. Afterwards she wants to precipitate all the lead. She wants to use a solution of aluminum sulfate to ...
Sunday, November 13, 2016 by John

Chemistry
will a precipitate form when 650 ml of 0.008 K2So4 is added to 175 ml of AgNo3 Ksp of Ag2So4=1.5*10^-5 Can any one tell me how to do it >? please
Sunday, November 13, 2016 by b.k

Chemistry
I am really having a hard time doing this question. We were asked to determine the iron content of spinach in a solution. We burned a 5.50g of spinach and added 10 ml of 2.0 M HCl in the spinach ashes. We mixed that and filtered the solution to removed the ashes. We used 5 ml ...
Sunday, November 13, 2016 by Shia

chemistry
Calculate the no.of moles (a)3.011 X 10power 23 atoms of He (b)1.505 X 10power23 of Co2 (c)6.022 X 10power23 atoms of Na (hint :nis equal to N/No)
Sunday, November 13, 2016 by Anonymous

Math (Algebra)
A chemistry student needs to make 60 liters of a 30% alcohol solution. He has a 20% alcohol solution and a 40% alcohol solution in the lab. How many liters of each strength does he need to mix together *The system of equations I did was: a+b=60 & .2a+.4b=18. I may be wrong but...
Saturday, November 12, 2016 by Amber

Chemistry
What is the minimum volume of 2.00 M hydrochloric acid necessary to neutralize completely the hydroxide in 800.0 mL of 0.3 M calcium hydroxide?
Saturday, November 12, 2016 by Kim

Chemistry
One-third cup of vanilla ice cream provides about 145 kcal of energy. A typical adult uses about 195 kcal/hr of energy while walking. If all of the energy in one third of a cup vanilla ice cream were to be burned off by walking, how many minutes would it take for this energy ...
Saturday, November 12, 2016 by Kay

Chemistry
How many mL of acetone are required to make a 8.42 % v/v aqueous solution in a 300 mL volumetric flask?
Saturday, November 12, 2016 by Hannah

Chemistry
How many Cu+2 ions are in 5.33 mol of CuCl2? I did this so far: n-> 5.33 mol Ncu-> ? ions M= 134.45 g =5.33 mol x (602x10^23 ions/ 1 mol) =3.21x10^24 ions
Saturday, November 12, 2016 by Sunny

Chemistry
Copper (I) chloride, CuCL, has Ksp = 1.9 x 10^ -7.calculate the molar solubility of CuCL in A)pure water, B)0.0200M HCl solution C) 0.200M HCl solution, and d) 0.150M CaCl2 solution. I used the ice table and for a) i got 0.000435 M sort of lost for the rest
Saturday, November 12, 2016 by priya

chemistry
If 200. mg of fluorine-18 is shipped at 7:00 A.M., how many milligrams of the radioisotope are still active when the sample arrives at the radiology laboratory at 4:10 P.M.?
Saturday, November 12, 2016 by Jae

chemistry
the word "proof" on alcoholic beverages is defined as twice the percentage by volume. How many ml of alcohol are in a one-liter bottle of 80-proof gin?
Saturday, November 12, 2016 by jen

chemistry
how much solute are present in a solution that contains 100.0g of water, and is 9.0% by weight sodium bicarbonate?
Saturday, November 12, 2016 by jen

chemistry
how many grams of potassium nitrate are needed to prepare 250.0ml of a 0.03M potassium nitrate solution?
Saturday, November 12, 2016 by jen

chemistry
calculate what volume of sulfuric acid solution(specific gravity=1.07;and containing 10%sulfuric acid by mass)contains 18.50g of pure sulfuric acid at a temperature of 25 Celsius.
Saturday, November 12, 2016 by jen

chemistry
what volume of a 0.20M potassium sulfate solution contains 57g potassium sulfate?
Saturday, November 12, 2016 by jen

chemistry
Suppose 5 ∫ f(x)dx=6 ∫ 2 3 ∫ f(x)dx=1 ∫ 2 5 ∫ f(x)dx=4 ∫ 4 4 ∫ (6f(x)−1)dx= ? ∫ 3 help, please? I got the answer of 5, but it says its wrong
Friday, November 11, 2016 by angie

Chemistry
Consider the neutralization reaction that takes place when hydrochloric acid reacts with aqueous calcium hydroxide Write a complete balanced equation for this reaction
Friday, November 11, 2016 by Kayla

chemistry
how much CuSo4•5H2O will precipitate from a aq. soln of CuSO4, 25g dissolved in min amnt of water at 60C then cooled at 0C. Solubility of CuSO4 at 60C in 100 mL H2O is 40 g and in 0C is 15g.
Friday, November 11, 2016 by lizs

Chemistry
1) how many joules are required for each of the following? A)Heating 55g of water from 12 degree Celsius to 76 degree Celsius B) Melting 12.8g of ice at 0 degree Celsius. c) Boiling 21.1 g of water at 100 degree Celcius
Friday, November 11, 2016 by Keliane

chemistry
At 25ºC and 1 atmosphere the following equilibrium is eatablished : 2NO (g) <=> N2O4 (g) The partial equilibrium pressure of N2O4 is 0.7 atm. A) calculate Kp of the above system at 25ºC. B) calculate the partial pressure of the above two gases at equilibrium when the ...
Friday, November 11, 2016 by angy

chemistry
when a quantity of powdered sulphur is burnt in excess oxygen, 100cm3 of SO2 were produced at STP CAL,the vol of gas at STD
Friday, November 11, 2016 by stephen

Chemistry
Determine the mass of iron in the following solution. 325mL of 0.050 M FeSO4.
Friday, November 11, 2016 by please help me out i forgot to add something)

Chemistry
Determine the mass of iron in the following solution. 325mL of FeSO4.
Friday, November 11, 2016 by please help me out

Chemistry
Nitrogen (80 kPa), oxygen (21.0 kPa), carbon dioxide (0.03 kPa), and water vapor are the usual components of air. What is the partial pressure of water in mm Hg if the total atmospheric pressure in 1.00 atm?
Friday, November 11, 2016 by Anonymous

Chemistry
What is the solute-solvent interaction between silver nitrate in water?
Friday, November 11, 2016 by Someone

Analytical chemistry
Why HNO3 only can used for acidification in volhard method not other acids like HCl or H2SO4?
Friday, November 11, 2016 by Amal

Chemistry (molarity)
How would I find the moles of NaOH solution that was used to titrate? I have 20.01mL of HCl used and 15.95mL of NaOH solution was used to titrate.
Thursday, November 10, 2016 by Ray

Chemistry
What is the molarity of the final solution of 2.00mL of the 5.00M stock solution is diluted to 10.00mL to make solution A. Solution A undergoes a second dilution by taking 3.00mL solution A and diluting it to 25mL? I'm so confused by this. Please help.
Thursday, November 10, 2016 by jamie

Chemistry
Explain how a ligand can be both sigma donating and pi donating and give an example of a ligand that does both. Is this ligand a Lewis acid or a Lewis base? Thank you!
Thursday, November 10, 2016 by Saki

Chemistry (molarity)
What would the effect on your molarity of NaOH be if you had added 35 mL of water to dissolve the KHP (acid) instead of 25 mL? Explain. My answer so far is that adding more water shouldn't affect the molarity at all because water does not account for the reaction between NaOH ...
Thursday, November 10, 2016 by Ray

Chemistry
Hydrocarbons with octane number 78% and 73%, by comparing their burning abilities, which one can burn smoothly? And why?
Thursday, November 10, 2016 by Atakpa Science College

Chemistry
For the following redox reaction, give the complete reduction half reaction. Na(s) + Al+3(aq) Na+1(aq) + Al(s) Please help asap!!
Thursday, November 10, 2016 by Rae

chemistry
What is the shape and bond angle of PH3? Explain
Thursday, November 10, 2016 by dukes

Chemistry
CH4 + 2O2 --> CO2 + 2H2O a. How many grams of methane are needed to produce 1.5 X 10^-2 grams of carbon dioxide? b. How many grams of oxygen are needed to react to form the 1.5 X 10^-2 grams moles of carbon dioxide?
Thursday, November 10, 2016 by John

Chemistry
CH4 + 2O2 --> CO2 + 2H2O a. How many grams of methane are needed to produce 1.5 X 10^-2 grams of carbon dioxide? b. How many grams of oxygen are needed to react to form the 1.5 X 10^-2 grams moles of carbon dioxide?
Thursday, November 10, 2016 by John

Chemistry
CH4 + 2O2 --> CO2 + 2H2O a. How many grams of methane are needed to produce 1.5 X 10^-2 grams of carbon dioxide? b. How many grams of oxygen are needed to react to form the 1.5 X 10^-2 grams moles of carbon dioxide?
Thursday, November 10, 2016 by John

chemistry
Which is more ionic LiF or NaF and why
Thursday, November 10, 2016 by dukes

Chemistry
Based on chemical structures, explain why acetophenone is only separated at the end by distillation. The mixture was acetophenone and ethyl trimethylacetate
Thursday, November 10, 2016 by Lyndsay

Chemistry
what would the concentration of the solution of a sulfuric acid be titration of a 25.0 ml sample of acid required 20.00 ml of a 0.20 naoh standardized solution for it to become neutralized
Thursday, November 10, 2016 by Jay

Chemistry
Write mathematical equations that show how you will calculate the detected activity from the count rate due to background radiation and the sample of KCl and how you will determine the “true” activity of your sample from the detected activity. Use the following symbols: (3...
Thursday, November 10, 2016 by Annie

Physical chemistry
Find ΔG and ΔA for the freezing of 1.00 mol of H20 at 0°c and 1atm. At 0 ° C and 1 atm the density of ice and liquid water are 0.917 g / mL and 1 g / mL, respectively.
Wednesday, November 9, 2016 by Jenna

Chemistry
For the reaction, calculate how many grams of the product form when 3.0 g of Mg completely reacts. Assume that there is more than enough of the other reactant. 2Mg(s)+O2(g)→2MgO(s)
Wednesday, November 9, 2016 by Liselle

Help?? Chemistry?
If it takes 20.0 mL of 1.200 M KOH to neutralize 60.0 mL of a given H3PO4 solution, what is the molarity of this phosphoric acid solution? I've figured out that the neutralization of phosphoric acid by the addition of potassium hydroxide in aqueous solution: H3PO4 + 3 KOH ->...
Wednesday, November 9, 2016 by Anonymous

Chemistry
1.000 grams of KHP consumed 43.3 mL of KOH solution. What is the molarity of the KOH solution?
Wednesday, November 9, 2016 by Anonymous

Chemistry
Given 1 cc of Zinc and 1 cc of Cr What is the mass difference?
Wednesday, November 9, 2016 by John

Clinical chemistry
Why do we use normal saline to dilute serum instead of distilled water ?
Wednesday, November 9, 2016 by Azal akawi

Chemistry
What mass of water is needed to completely react a 8.1 g packet of magnesium
Wednesday, November 9, 2016 by Dina

Chemistry II
Calculate the volume of oxygen at 10 degrees Celsius and 1.6 atm pressure that can be produced by decomposing 128g of hydrogen peroxide
Wednesday, November 9, 2016 by Darneth

Chemistry
Calculate the new molarity of a 20.0 mL sample of 0.550 M CaCl2 solution that is diluted with water to make 250 mL of solution.
Wednesday, November 9, 2016 by Anonymous

plz..chemistry help
One mole of solid NH4Cl (s) isvheated in a closed box to decompose it partially according to the following reaction:  NH4Cl (s) <=> NH3 (g) +HCl (g)  A) calculate Kp of the above system at the temperature of the experiment if the partial pressure of ammonia at ...
Wednesday, November 9, 2016 by hannah

chemistry
What is the molar solubility of silver carbonate, Ag2CO3?
Wednesday, November 9, 2016 by bb

chemistry
One mole of solid NH4Cl (s) isvheated in a closed box to decompose it partially according to the following reaction: NH4Cl (s) <=> NH3 (g) +HCl (g) A) calculate Kp of the above system at the temperature of the experiment if the partial pressure of ammonia at equilibrium ...
Wednesday, November 9, 2016 by hannah

Chemistry
How do i prepare KH2PO4-KOH buffer 0.2 M of pH 7.4?
Tuesday, November 8, 2016 by Nazneen

AP Chemistry
Q - An electrochemical reaction occurs between an unknown element and zinc. The half-cell reaction for the zinc is: Zn(s) → Zn2+(aq) + 2e− The cell potential for the reaction is Eºcell = 1.83 V. Is the reaction spontaneous or nonspontaneous? Explain. What is the half-cell...
Tuesday, November 8, 2016 by Ned

Chemistry
Reaction between ethyl acetate and water attain equilibrium in an open vessel but decomposition of caco3 does not.explain.
Tuesday, November 8, 2016 by Gurleen

chemistry
What intermolecular forces must be overcome in converting each of the following from liquid to gas? (i) Liquid O2 (ii) Mercury (iii) CH3I (methyl iodide) (iv) CH3CH2OH (ethanol
Tuesday, November 8, 2016 by rotendelwa

Chemistry
How many milliliters of 0.540 M sodium sulfate solution would be needed to precipitate the calcium ion from 60.0 mL of 0.180 M CaCl2 solution?
Tuesday, November 8, 2016 by Anonymous

Chemistry
What is the weight percent of a potassium iodide [KI] solution that is made by dissolving 47.2 grams of KI in 152.8 grams of water?
Tuesday, November 8, 2016 by Anonymous

Chemistry
3Fe2+(aq) + 2Al(s) --> 3Fe(s) + 2Al3+(aq) Which of the following statements is true about Fe2+? 1.Fe2+ is losing electrons. 2.Fe2+ is oxidized. 3.Fe2+ is the oxidizing agent. 4.Fe2+ is the reducing agent.
Tuesday, November 8, 2016 by Rae

Chemistry
What mass of hydrogen gas is produced when 3.0 mol of iron react with excess hydrochloric acid according to the reaction below 2Fe + 6HCl --> 2FeCl3 + 3H2
Tuesday, November 8, 2016 by Mary

Chemistry
What mass of hydrogen gas is produced when 3.0 mol of iron react with excess hydrochloric acid according to the reaction below 2Fe + 6HCl --> 2FeCl3 + 3H2
Tuesday, November 8, 2016 by Mary

Chemistry
What mass of hydrogen gas is produced when 3.0 mol of iron react with excess hydrochloric acid according to the reaction below 2Fe + 6HCl --> 2FeCl3 + 3H2
Tuesday, November 8, 2016 by Mary

Chemistry
What mass of hydrogen gas is produced when 3.0 mol of iron react with excess hydrochloric acid according to the reaction below 2Fe + 6HCl --> 2FeCl3 + 3H2
Tuesday, November 8, 2016 by Mary

Chemistry
What mass of hydrogen gas is produced when 3.0 mol of iron react with excess hydrochloric acid according to the reaction below 2Fe + 6HCl --> 2FeCl3 + 3H2
Tuesday, November 8, 2016 by Mary

Chemistry
What volume in dm³ of KCl is obtained in the following equation 2KClO3-----> 2KCl + 3O2?
Tuesday, November 8, 2016 by Summit

chemistry
estimate the ph of an aqueous solution of each of the following compounds by indicating whether the ph is greater than 7 or less than 7 or about 7. H3PO4 Mg(OH)2 NaNO3 HNO3 NH3(aq) (NH4)2CO3 CO2 KC2H3O2 HC2H3O2 KCL
Tuesday, November 8, 2016 by ann

Chemistry
Define the law of the conservation of mass. Using this definition: if you have the reaction of 40 g of water decomposing into hydrogen and oxygen what would be the total mass of your products?
Tuesday, November 8, 2016 by Please help

chemistry
How would you prepare 1. 100 ml of 0.20 M Ca(OH)2 from 0.50 M Ca(OH)2
Tuesday, November 8, 2016 by casey

chemistry
Nitrogen gas can be prepared by passing gaseous ammonia over solid copper (II) oxide at high temperature. The other products of the reaction are solid copper and water vapor. If a sample containing 20.3 g of NH3 is reacted with 95.8 g of copper oxide 1. Which is the liming ...
Tuesday, November 8, 2016 by casey

Chemistry
what kind of reaction is this Sr(NO3)2 (aq) + K2CrO4 (aq) = SrCrO4 (S) + 2KNO3 (aq) and does it take place or NR, why?
Tuesday, November 8, 2016 by ina

Chemistry
80.0 ml of 1.50 M lead (IV) acetate is added to a 65.5 ml solution of 1.25 potassium chloride. 5.84 grams precipitate are collected. what is the percent yield? Calculate the concentrations of all ions remaining in solution. Okay so I know you have to convert to moles of each ...
Monday, November 7, 2016 by Kenzie

Chemistry
How do you create a calibration curve? How do you use a calibration curve to convert absorbance to concentration in mg/mL?
Monday, November 7, 2016 by Sal

chemistry
P4 + 6 Br2 -> 4PBr3 In a particular reaction, 20 grams of phosphorus P4, is combined with 50mL liquid bromine ( Density= 2.93 g/ml) 1) Calculate the mass of product in grams for each of the reactants 2) Limiting reagant and Mass Maximum mass of PBr3 so for 1) I converted ...
Monday, November 7, 2016 by jake

Chemistry
Please Help me!! NaCl(aq)+Hg2(C2H3O2)2(aq)→ Express your answer as a chemical equation. Enter noreaction if no precipitate is formed
Monday, November 7, 2016 by Liselle

chemistry
A 9.35 gram of ring with it's volume of 0.654 cm3 is an alloy of gold and with density of gold and silver respectively 19.3 g/cm3 and 10.5 g/cm3 assume there is no change in volume when pure metals are mixed. calculate volume of gold?
Monday, November 7, 2016 by Anonymous

chemistry
A 9.35 gram of ring with it's volume of 0.654 cm3 is an alloy of gold and with density of gold and silver respectively 19.3 g/cm3 and 10.5 g/cm3 assume there is no change in volume when pure metals are mixed. The volume of gold is?
Monday, November 7, 2016 by sami

Chemistry
Can you check my answers? Thanks!!!! What would happen to the volume-to-temperature ratio if: 1. One student failed to replenish the boiling water in the boiling-water bath as the flask was being heated. At the end of the 6 min of heating, the boiling water in the bath was ...
Monday, November 7, 2016 by Steve

chemistry
Calculate the volume of HNO3 that must be introduced in the calorimeter,knowing that it were used 60 ml NaOH, Cc=100cal/grd and delta H=-13,5 kcal/mol.. please help me,i have no clue for this..
Monday, November 7, 2016 by Alberto

Chemistry
Calculate enthalpy of reaction C2H4 + H2 gives C2H6.enthalpy of combustion of ethene, H2,and ethane are -1410,-286,-15.60kj/mol respectively
Monday, November 7, 2016 by Shaika

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