Thursday
September 29, 2016

Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

chemistry
How many grams of nacl are required to completely neutralize 100 ml of 1M h2so4?
Thursday, September 8, 2016 by joe

Chemistry
Why is it that copper (II) sulfate with barium hydroxide --> copper hydroxide (solid) + barium sulfate (solid)? According to the solubility rules given to me by my professor, both are insoluble, and therefore should be labeled as solids. Is there something I'm missing ...
Thursday, September 8, 2016 by Tom

Chemistry
Why is it that copper (II) sulfate with barium hydroxide --> copper hydroxide (solid) + barium sulfate (solid)? According to the solubility rules given to me by my professor, both are insoluble, and therefore should be labeled as solids. Is there something I'm missing ...
Thursday, September 8, 2016 by Tom

AP Chemistry
The reaction of 5.7 grams of fluorine with excess chlorine produced 7.6 grams of ClF3. What percent yield of ClF3 was obtained? Answer in units of %.
Wednesday, September 7, 2016 by Rachel

Chemistry
A saline solution used in intravenous drips for patients who cannot take oral fluids contains 0.92% (w/v) NaCl in water. How many grams of NaCl are contained in 250 mL of this solution? So wouldn't it just be .92%= .92 grams x 250ml.../100= 2.3 g NaCl?
Wednesday, September 7, 2016 by Petey

Chemistry
Larry has 250.00 ml of water. The water currently holds the maximum amount of soluble Silver iodide. In a separate container, Larry has 96 ml of a 0.07M solution of sodium carbonate. He wants to precipitate out all of the silver. Of his 96 ml, how much will he have to pour ...
Wednesday, September 7, 2016 by John

Chemistry
Using a closed system experiment will a leak during gas evolving reaction overstate or understate the amount of sodium bicarbonate in an alka seltzer cold tablet?
Wednesday, September 7, 2016 by Anonymous

Chemistry
Element X has 6 protons, 8 neutrons, and 6 electrons. Predict the atomic mass of element X?
Wednesday, September 7, 2016 by Anonymous

chemistry
How do you seperate this into ions Na2B4O7
Wednesday, September 7, 2016 by byu

Chemistry
Do you think the copper and zinc underwent a physical change or a chemical change?
Wednesday, September 7, 2016 by Emily

Chemistry
A scientist used 21.0g of NaHCO3. How many miles of NaHCO3 were in this sample?
Wednesday, September 7, 2016 by Diana

Chemistry
How many grams of NaOH would you dissolve in pure water to make 400 mL of a 2.5% NaOH solution ? MW of NaOH = 40 g/mol
Wednesday, September 7, 2016 by Jay

Chemistry(please check my answer)
When a radioactive isotope undergoes Beta Decay, which of the following will NOT occur? A. The mass number of the original nucleus changes. B. The atomic number of the original nucleus changes. C. The original nucleus approaches greater stability. D. Energy is released.***
Wednesday, September 7, 2016 by Cherry

Chemistry(please check my answer)
A radioactive isotope of radium (Ra-226) has a half-live of 1620 years. How much of this isotope remains after three (3) half-lives? A. 1/2 B. 1/4 C. 1/8*** D. None
Wednesday, September 7, 2016 by Cherry

Chemistry(please check my answer)
Which of the following is true concerning gamma radiation? A. The mass number of the radioisotope decreases by four. B. The atomic number of the radioisotope decreases by two. C. The atomic number of the radioisotope increases by one. D. Neither the mass number nor the atomic ...
Wednesday, September 7, 2016 by Cherry

Chemistry
"Aluminum metal melts at 658.5°C. What would be the final temperature if 28.0 grams of solid aluminum at this temperature were placed into 520 grams of liquid aluminum at 1000.0°C? The heat of fusion for aluminum is 396 J/g, and the specific heat of liquid ...
Wednesday, September 7, 2016 by Tiffany

Organic chemistry
How many nodes are in the pi* orbital of a carbon-carbon double bond? Please explain. Thanks in advance.
Wednesday, September 7, 2016 by Bill

chemistry
student places a 23.80 g solid metal object in a graduate cylinder containing 26.5 mL of water. The water level increases to 32.1 ml after the object is submerged. Calculate the density of the object.
Wednesday, September 7, 2016 by Anonymous

Chemistry
Confused, conflicting texts when you are finding % error for density formula: experienced value-accepted value/ accepted value ×100. Does the ×100 cancel out the percent sign? EX; 7.28g/mL-6.54g/mL/6.54g/mL ×100. Is the answer 11.31 or 11.31% The lab video ...
Wednesday, September 7, 2016 by lulu

chemistry
calculate the mass of silver deposited when a current of 3ampere is passed through a solution of a silver salt for 7minutes
Wednesday, September 7, 2016 by precious

ma
In a class of 100 students, 40 failed in Math, 30 failed in Physics, 60 failed in Chemistry. 35 passed in both Math and Physics. 20 passed in Physics and Chemistry. 25 passed in Math and Chemistry. Each student passed in at least one subject. How many students passed in all ...
Wednesday, September 7, 2016 by Anonymous

chemistry
mass of empty flask plus stopper 36.765 g mass of stoppered flask plus water 65.264 g Temperature 24.8 C calculate the volume? need help please
Tuesday, September 6, 2016 by finny

Chemistry
One isotope of a metallic element has mass number 10 and has 7 neutrons in the nucleus. It forms an atomic ion having 2 electrons. Enter the symbol for this ion
Tuesday, September 6, 2016 by Aaron

physics
How do the laws of physics apply to others sciences such as biology chemistry and earth science? And give an example to show the connection.
Tuesday, September 6, 2016 by nulloa

Chemistry
Upon decomposition, one sample of Magnesium Fluoride produced 1.65 kg of magnesium and 2.57 kg of fluorine. A second sample produces 1.33 kg of magnesium. How much fluorine (in grams) did the second sample produce?
Tuesday, September 6, 2016 by Bri

Chemistry
"Calculate the enthalpy of vaporization of water given that, when 5.00 grams of steam (gaseous H2O) at 100°C was introduced into a beaker containing 500 grams of water at 20.0°C, the temperature rose to 26.2°C." q_H2O(l) + q_H2O(g)= E nΔH_vap + ...
Tuesday, September 6, 2016 by Tristan

Chemistry
"Aluminum metal melts at 658.5°C. What would be the final temperature if 28.0 grams of solid aluminum at this temperature were placed into 520 grams of liquid aluminum at 1000.0°C? The heat of fusion for aluminum is 396 J/g, and the specific heat of liquid ...
Tuesday, September 6, 2016 by zoeymadison486

Chemistry - Enthalpy
"Calculate the enthalpy of vaporization of water given that, when 5.00 grams of steam (gaseous H2O) at 100°C was introduced into a beaker containing 500 grams of water at 20.0°C, the temperature rose to 26.2°C." H2O (l) -> H2O (g) ΔH = ΔH_vap...
Tuesday, September 6, 2016 by Samantha

Chemistry
1.What two sets of units can be used to describe density? Why are they interchangeable? ~~~~~ I'm not sure what it means with units? Like grams and such? And what do they mean by interchangeable?
Tuesday, September 6, 2016 by Astral Tellurian

chemistry
how do i prepare a sulphuric acid solution having 75 % purity with 1.68 specific gravity from sulphuric acid with 97 % purity and 1.834 specific gravity.
Tuesday, September 6, 2016 by Mukesh

Chemistry
How much heat is evolved in converting 1.00 mol of steam at 155.0 ∘C to ice at -45.0 ∘C? The heat capacity of steam is 2.01 J/(g⋅∘C) and of ice is 2.09 J/(g⋅∘C).
Monday, September 5, 2016 by Caleb

Chemistry
How many grams of ice are needed to cool 250 ml of water from 75 degrees Celsius to 5 degrees Celsius? (m_ice * 6.01kJ) + (m_ice * 4.18J/g°C * (5-75°C) = -[250mL * 4.18J/g°C * (5-75°C)] ???
Monday, September 5, 2016 by Mikey

Chemistry
A piece of metal with a mass of 131 g is placed in a 50 mL graduated cylinder. The water level rises from 20. mL to 35 mL. What is the density of the metal?
Monday, September 5, 2016 by Lean brow

P-Chemistry
A closed vessel of volume 2.50 dm3 contains 100g of nitrogen (N2) and 100g of carbon dioxide (CO2) at 25 C. What are the partial pressures and mole fractions of each gas? Can you check my answers.Thank you. I got Partial Pressure for N2=34.95 atm CO2=22.24 atm Mole fraction of...
Monday, September 5, 2016 by Jessy

P-Chemistry
A closed vessel of volume 2.50 dm3 contains 100g of nitrogen (N2) and 100g of carbon dioxide (CO2) at 25 C. What are the partial pressures and mole fractions of each gas?
Monday, September 5, 2016 by Jessy

Chemistry
two aqueous solutions (solution A and solution B) contain different non reactive solutes and have densities of 1.021 g/ml and 1.190 g/ml, respectively. when 40.00 ml of solution A is mixed with 10.00ml of solution B what is the density of the mixture? im not entirely sure how ...
Monday, September 5, 2016 by Anonymous

Chemistry Help Please!
At most, how many 4d electrons can an atom have? Of these what is the maximum number that can have ms= -1/2? A 5f electron has what value of quantum number l? What values of ml may it have? Also please explain how you got the answers so I can understand? Thank you so much!
Monday, September 5, 2016 by Kim

Chemistry
Why is it important to keep the beaker containing the mobile phase covered while preparing your chromatography paper and developing your chromatograms?
Monday, September 5, 2016 by Steve

chemistry
i.Calculate the volume of carbon ivoxide given off at stp when 20gram of octane is burnt in excess air (c=12,1+=1 gmv of any gass is 22.4dm^3 at stp). ii. Deduce the formula of a hydrocarbon with general formula cnH2n-2 of its molar mass in 110.
Monday, September 5, 2016 by lawrence

Chemistry
If the density of carbon is 3.51 g/cm3, and you have a small diamond (pure carbon) that has a mass of 0.0270 grams, what is the volume?
Sunday, September 4, 2016 by Courtney

Analytical Chemistry
Calculate the hydroxide concentration of a solution that is 0.1 F with NH3, and 0.25 F in respect to (NH4)2S04.
Sunday, September 4, 2016 by juni

Chemistry
How much heat energy is required to heat up 50.0 grams of water from 20.2 degrees Celsius to 34.2 degrees Celsius? I want o use the Q=mc(change in temp) formula but I am only given the m and difference in temp in this question so I am not sure of what I am supposed to do.
Sunday, September 4, 2016 by Kaitlyn

Chemistry
The density of diamond is 3.51g/cm^3,and the density of platinum is 21.43g/cm^3.If equal masses of diamond and platinum are transferred to equal volumes of water in separate graduated cylinders,which graduated cylinder would have the greatest volume change? Explain or show ...
Sunday, September 4, 2016 by Alasow

Chemistry
At 603 K, Kc for the reaction NH4Cl <===> NH3 + HCl is 0.011. What is the equilibrium concentration of NH3 if the initial concentration of NH4Cl is 0.500 M. Please help me with this question because i got 2 answers so prove me.
Sunday, September 4, 2016 by Enoch

Chemistry
At 603 K, Kc for the reaction NH4Cl <===> NH3 + HCl is 0.011. What is the equilibrium concentration of NH3 if the initial concentration of NH4Cl is 0.500 M. Please help me with this question because i got 2 answers so prove me.
Sunday, September 4, 2016 by Enoch

Chemistry
How many grams of NaN₃ must be decomposed to fill a 42.0 L airbag with nitrogen gas at a pressure of 1.05 atm and a temp of 29.5 degrees Celsius?
Saturday, September 3, 2016 by Hugh

Chemistry
What substance is acting as the Brønsted-Lowry base in the forward reaction below? H2O + NH3 yields NH4+ + OH-
Saturday, September 3, 2016 by MONICA

Chemistry, Heat and Phase changes(general chem II)
From the data below, calculate the total heat (in J) needed to convert 22.00 g of icea t -6.00 C to liquid water at 0.500 C. melting point at 1 atm: 0.0 C Hfusion: 6.02 KJ/mol cliquid: 4.21 J/g C csolid: 2.09 J / g C My answer is about 300 J short of the correct answer. It ...
Saturday, September 3, 2016 by Dean

Chemistry
Hello I need help with this excersise: How many moles of NH4Cl are neccesary to add to 1 liter of solution of Co2+ 0,20 M in order to prevent the precipitation when the solution is saturated with H2S (0,1M) and the pH is 7,50. It 's known that pKbNH3=4,75 ; Kps(CoS)=2,0&...
Friday, September 2, 2016 by Mary

Organic Chemistry
Would a C-Cl bond be polar or nonpolar in a molecule if both have a formal charge of 0? I thought at first that it would be polar just due to their electronegativities (just by looking at the periodic table), but if they both have a formal charge of 0, does that make it a ...
Friday, September 2, 2016 by Este

Chemistry
The homework question said "which 2nd row element has 6 valence electrons and a valence of 2?" I don't really understand the question, because oxygen would be the element with the 6 valence electrons, but wouldn't that mean that it has a valence of 6? Does ...
Friday, September 2, 2016 by Jen

CHEMISTRY
CALCULATE THE DECREASE IN TEMPERATURE FOR 22.0 G SILVER THAT LOSES 625 J
Friday, September 2, 2016 by MARY

Chemistry
How much 3M HCL will be used in order to prepare 250ml of 1M HCL
Friday, September 2, 2016 by Pp1412

chemistry
How to determine saturation point of k2Cr2O7?
Friday, September 2, 2016 by ang

Chemistry
Mg + HCl -------> MgCl2 + H2 What volume of HCl is required from 27 % HCl to form 12.1 gram H2? ( D = 1.41 g/ml)
Friday, September 2, 2016 by Majid

Chemistry
how many joules of energy are needed to change 400 grams of water from 35 degrees C to 45 degrees C?
Thursday, September 1, 2016 by helpneeded

Chemistry
Calculate the volume of 1.0 M CuSO4 stock solution you should use to make 100 mL of a 0.010 m CuSO4 solution.
Thursday, September 1, 2016 by Brianna

Chemistry
How do I calculate the amounts of Na2SO4 and CaCl2 that I need to create a solution of CaSO4 at 9 grams/Liter concentration?
Thursday, September 1, 2016 by Kato

Chemistry
How many electrons in CH3NH3+ ?
Thursday, September 1, 2016 by anon

Chemistry
Which is a conjugate pair in the following equilibrium? H2C2O4(aq) + HPO4(aq) 2- HC2O4(aq)- + H2PO4(aq)-
Thursday, September 1, 2016 by Aidan

biology
which of the following is consistent with the theory of vitalism ? A.all matter contains a vital force** b.the chemistry of life and nonlife are similar c. living things contain a vital force absent in nonliving things d. life must be sustsained through a series of chemical ...
Thursday, September 1, 2016 by 9th grader

biochemistry
which of the following is consistent with the theory of vitalism ? A.all matter contains a vital force** b.the chemistry of life and nonlife are similar c. living things contain a vital force absent in nonliving things d. life must be sustsained through a series of chemical ...
Thursday, September 1, 2016 by 9th grader

chemistry
From a laboratory process designed to separate water into hydrogen and oxygen gas, a student collected 10.2 g of hydrogen and 66.9 g of oxygen. How much water was originally involved in the process?
Thursday, September 1, 2016 by melissa

Chemistry(please check my answer)
Which of the following is an oxidation reaction? A. AuCl4- → AuCl 2- **** B. Mn7+ → Mn2+ C. Cl2 → ClO3- D. Co3+ → Co2+
Thursday, September 1, 2016 by Cherry

Chemistry(please check my answer)
Among the following, which is an oxidation-reduction reaction? A. Na2S + CaCO3 → CaS + Na2CO3 B. 2HNO3 + Mg(OH)2 → Mg(NO3)2 + 2H2O C. H2 + F2 → 2HF**** D. 3Ba(OH)2 + 2H3PO4 → Ba3(PO4)2 + 6H2O
Thursday, September 1, 2016 by Cherry

Chemistry(please check my answer)
When the equation HCl + MnO2 → MnCl2 + H2O + Cl2 is balanced, what is the coefficient for HCl? A. 1 B. 2 C. 3 D. 4***
Thursday, September 1, 2016 by Cherry

Chemistry (please check my answer)
Identify a false statement about how to protect iron from corrosion. A. Coat the surface with oil, paint, or plastic. B. Attach a metal that is more easily reduced. ******* C. Exclude air and water. D. Attach a metal that is a better reducing agent.
Thursday, September 1, 2016 by Cherry

intergrated rate law chemistry
The decomposition of ammonia on a platinum surface at 1129 K occurs according to the following reaction: 2NH3 (g) ¨ N2(g) + 3H2(g). Use the following kinetic data which report the variation of ammonia concentration in the gas phase with time to evaluate the order of ...
Thursday, September 1, 2016 by chancy xdicey

chemistry
12M HCl + H20→ 5M HCl How much water? Total Volume= Pls I need this tomorrow
Thursday, September 1, 2016 by jack

Chemistry
Which of the following is true concerning the reaction below? H2S + HNO3 → S + NO + H2O A. S is reduced. B. H is oxidized. C. N is reduced. D. O is oxidized. ***
Wednesday, August 31, 2016 by Cherry

chemistry
it was found that in an experiment tthat a gas c diffuses 8.76¡Á10^-1 times faster than nitrogen gas calculate the molecular mass of gas c (n=14)
Wednesday, August 31, 2016 by saara

Chemistry
When 38.21 g of pure copper reacts with 192.83g of iodine, 190.83g of a compound containing only copper and iodine result. 40.21g of iodine remain when the reaction is complete. a. Do these results support the Law of Conservation of Mass? Explain. b.does this compund obey the ...
Tuesday, August 30, 2016 by Anonymous

Chemistry
Oxy acetylene welding uses acetylene gas which is produced by the reaction of CaC2 with water. It also produces calcium hydroxide as a by product.Calculate the volume in liters measured at 27°C and 965 torr that would be produced from the complete reaction of 11.2 g of ...
Tuesday, August 30, 2016 by Vaidehi

Chemistry
If a 29.9 g sample of the liquid cyclohexane has a volume of 38.6 mL, what is the specific gravity of the compound? Take the density of water to be 1.00 g/mL.
Tuesday, August 30, 2016 by Abby

Chemistry
A Helium Gas Ballon Has A Volume Of 12.0L. At Room Temperature(25 Degrees Celcius) The Internal Pressure Is .05ATM. Calculate The Number Of Moles Of Helium In The Balloon?
Tuesday, August 30, 2016 by Steve

Science, chemistry
During the experiment, 100ml will be required to prepare 0.5M solution of NaNO3. Calculate the mass of NaNO3 in grams that will be required.
Tuesday, August 30, 2016 by Hilen

chemistry
Answer the following questions about Fe(NO3)3. a. What is the mass percent of iron in this compound? b. A different iron compound is 34.43% by mass iron. What mass of this compound is needed to get 125g of pure iron?
Monday, August 29, 2016 by Alissa L

Chemistry
A 100.00g sample of the gaseous hydrocarbon ethane is a gaseous hydrocarbon, with 79.89g of carbon and 20.11g of hydrogen. Ethylene is a different gas phase hydrocarbon. A 100.00g sample of ethylene has 85.63g of carbon with 14.37 of hydrogen. A sample of a hydrocarbon has 64....
Monday, August 29, 2016 by Alissa L

Chemistry
At normal temperature and pressure, air has a density of 0.001184 g/mL. What is the mass of air in a room that is 3.93 m by 2.28 m by 2.25 m?
Monday, August 29, 2016 by Melanie

Chemistry
A solution is 40% acetic acid by mass. The density of this solution is 1.049 g/mL. Calculate the mass of pure acetic acid in 460 mL of this solution at 20 C. Answer in units of g.
Monday, August 29, 2016 by Melanie

Chemistry
I have no idea how to solve this problem could someone explain it to me please What will be the approximate volume when the temperature is 900 kelvin?
Monday, August 29, 2016 by Zoella

chemistry
What is the solubility of BaSO4 in a solution of 0.250 M Na2 SO4 ? The Ksp of BaSO4 is 8.7 x 10-11.
Monday, August 29, 2016 by elaine haizel

Chemistry
A salt water swimming pool is 47.0 m long, 25.1m wide, and 2.79 m deep. If the pool is filled with salt water having a density of 1.06 g/ cm3, how many pounds of salt water are in the pool when it is filled? 1 kg = 2.20 lb I'm not sure how to approach this. I've tried ...
Monday, August 29, 2016 by Jamie

chemistry
C2O4-- + I- + H+ ---> I2+CO2+H2O
Monday, August 29, 2016 by Vinay Pratap Singh

Organic Chemistry
The pKa of CH3COOH is 4.76. What statement describes a solution of CH3COOH at pH of 6.4?
Sunday, August 28, 2016 by Anonymous

Chemistry
7. A 100.00g sample of the gaseous hydrocarbon ethane is a gaseous hydrocarbon, with 79.89g of carbon and 20.11g of hydrogen. Ethylene is a different gas phase hydrocarbon. A 100.00g sample of ethylene has 85.63g of carbon with 14.37 of hydrogen. A sample of a hydrocarbon has ...
Sunday, August 28, 2016 by Alissa L

Bio physics chemistry pre medical
Methane react with steam to form h2 and co. . what volume of h2 can be obtained from 100cmcube of methane at the standard temperature and pressure? ?
Sunday, August 28, 2016 by Hania

Bio physics chemistry pre medical
The vitamin a has a molecular formula c 20 h 30 o. How much no of molecules will be vitamin a has in 500mg capsule?
Sunday, August 28, 2016 by Anonymous

Bio physics chemistry pre medical
Vitamin a has a molecular formula c 20 h 30 o. How much no of molecules will vitamin a contian in 500mg capsule? ? Plz tell me now tomorrow is my test .I will be very grateful of u. .
Sunday, August 28, 2016 by Hania

Chemistry
Dissolved 0.7500 g calcium chloride dihydrate and impure, in distilled water and the volume was elevated to 200.00 mL in a volumetric flask. A rate of 10.00 mL of the same consumed the titration 18.9 mL 0.0125 M EDTA using CALCON as indicator. What is the purity of the salt...
Sunday, August 28, 2016 by Damon

Chemistry
How many potassium ions are present in the following: 1) 3 moles of potassium chloride.
Sunday, August 28, 2016 by Nicole

Bio physics chemistry pre medical
Vitamin a has a molecular formula c 20 h 30 o. How much no of molecules will vitamin a contian in 500mg capsule? ? Plz tell me now tomorrow is my test .I will be very grateful of u. .
Sunday, August 28, 2016 by Hania

Bio physics chemistry pre medical
Methane react with steam to form h2 and co. . what volume of h2 can be obtained from 100cmcube of methane at the standard temperature and pressure? ?
Sunday, August 28, 2016 by Hania

Chemistry
if 12.8g of NaCl is added to 243.2 mL of water (density (1.00g/mL)). the volume occupied by the solution is 250.0 mL. Calculate the density of the salt water.
Sunday, August 28, 2016 by Anonymous

Chemistry
The weight of kclo3 which thermal decomposition o2 gas sufficient for the combustion of 1.12 litres of ethlene gas at STPis
Sunday, August 28, 2016 by Anonymous

Chemistry
One volume of a hydrocarbon require 3 volume of oxygen for complete combustion then formula for hydrocarbon
Sunday, August 28, 2016 by Anonymous

Chemistry
How many electrons involved in the reduction of one mole of Al2o3 to aluminium metal
Sunday, August 28, 2016 by Anonymous

Chemistry
How many moles of potassium permanganate is necessary to oxidise o.5 moles of soadium sulphate in acid medium
Saturday, August 27, 2016 by Anonymous

Chemistry
A flask of known volume was filled with air to a pressure of 3.6atm. This flask was then attached to an evacuated flask of known volume and the air was allowed to expand into the flask. The final pressure of the air (in both flasks) was 2.7atm and the volume of the second ...
Saturday, August 27, 2016 by Scott

Chemistry
Dissolved 0.7500 g calcium chloride dihydrate and impure, in distilled water and the volume was elevated to 200.00 mL in a volumetric flask. A rate of 10.00 mL of the same consumed the titration 18.9 mL 0.0125 M EDTA using CALCON as indicator. What is the purity of the salt...
Saturday, August 27, 2016 by Damon

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Homework Help: Science