Wednesday
May 22, 2013

# Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

Chemistry
Zinc metal reacts with hydrochloric acid according to the following equation: Zn + 2HCl yields ZnCl2 + H2. How many grams of hydrogen gas can be obtained if 50.0 g of zinc react completely?
Monday, March 11, 2013 at 1:41pm

chemistry
how do you convert .99grams of copper to moles using the atomiuc weight
Monday, March 11, 2013 at 1:38pm

Chemistry
I don't really know how to go about this, Please help 1. Calculate the number of moles of the gas. Calculate the volume the gas would occupy at 100.0 C and 15.0 atm. 10.8 g He 2. Given the volume of 54.0 C and 790 torr, calculate the number of moles and mass. 38.1 L CO
Monday, March 11, 2013 at 1:11pm

chemistry
Calculate mole fraction of solution made by mixing 46gram alkohol in 360 gram water at given temperature?
Monday, March 11, 2013 at 8:09am

chemistry
Calculate mole fraction of solution made by mixing 46gram alkohol in 360 gram water at given temperature?
Monday, March 11, 2013 at 8:09am

chemistry
a 2.50mL sample of dry air in a cylinder exerts a pressure of3.00atm at room temperature. without changing the temperature, a piston is moved until the pressure in the cylinder is reduced to 1.00atm. what is the final volume of the gas?
Monday, March 11, 2013 at 7:54am

chemistry
a 2.50mL sample of dry air in a cylinder exerts a pressure of3.00atm at room temperature. without changing the temperature, a piston is moved until the pressure in the cylinder is reduced to 1.00atm. what is the final volume of the gas?
Monday, March 11, 2013 at 7:21am

chemistry
20mL ethanol(density=o.789g/mol) is dissolved in sufficient water to produce a 200mL solution. the density of the solution is 0.982g/mL. what is the molarity?
Monday, March 11, 2013 at 7:19am

Chemistry
I'm working on a problem dealing with calculating the heat of vaporization for vapor pressures problem. By substituting the problems values into the Clausuis-Clapeyron equation I get: .642= (2.28x10-5) x Delta H vap (J/mol) However, from this point I don't know how to ...
Monday, March 11, 2013 at 2:34am

Chemistry
How much salt could an average person hold? (Ignore safety concerns) Given equation: 0.3x=y 0.3x meaning mass of water y mean mass of salt that could be dissolved in the given mass of water Assuming the average human body has 60-75% of water, let us just use 75% Solve.
Monday, March 11, 2013 at 1:03am

Chemistry
Give a real life scenario in which solubility is important that does NOT involve salt and water.
Monday, March 11, 2013 at 1:01am

Chemistry
A sample of gas weighs 2.832g and has a volume of 1010.0 ML at 775.0 torr and 31.0 degrees Celsius what is its molar mass?
Monday, March 11, 2013 at 12:12am

chemistry
What mass of F2 is needed to produce 116 g of PF3 if the reaction has a 77.4% yield?
Sunday, March 10, 2013 at 11:17pm

Chemistry
what mass in grams of sodium hydroxide is produced if 20.0g of sodium metal reacts with excess water according ro the chemical equation, Na(s)+H2O4->naoh(aq)+h2(g)
Sunday, March 10, 2013 at 11:07pm

Chemistry
Water has an extremely high boiling point compared to other compounds of similar molar mass because of ? Hydrogen Bond Adhesive force Covalent bonding Dispersion Forces I believe the answer is A since hydrogen bond is a strong bond and thus require most energy to break them. ...
Sunday, March 10, 2013 at 10:50pm

chemistry
1L of a buffer composed of acetic acid and sodium acetate has a pH of 4.3. Adding 10mL of 2M sodium hydroxide solution to 100mL of this buffer causes the pH to rise to 4.87. what is the total molarity of the original buffer?
Sunday, March 10, 2013 at 10:18pm

chemistry
1L of a buffer composed of NaHC2O4 and Na2C2O4 has a pHof 4.0 and a total molarity of 1. a). what would the effect on the pH be of adding 1 gram of sodium hydrogen oxalate to this buffer? b). what would be the effect on the pH of adding 1 gram of sodium oxalate to the original...
Sunday, March 10, 2013 at 10:00pm

Chemistry
How do I find the number of particles in 1 pound of NH3(Ammonia)?
Sunday, March 10, 2013 at 9:35pm

chemistry
Ethanol, C2H5OH, is being promoted as a clean fuel and is used as an additive in many gasoline mixtures. Calculate the ΔH°rxn for the combustion of ethanol. ΔH°f [C2H5OH(l)] = -277.7 kJ/mol; ΔH°f [CO2(g)] = -393.5 kJ/mol; ΔH°f [H2O(g)] = -...
Sunday, March 10, 2013 at 9:21pm

chemistry
Find the concentration of Ag+ in a saturated solution of AgBrO3 that also contains 0.02M LiNO3, 0.02M KClO4 and 0.01M NaF.
Sunday, March 10, 2013 at 7:24pm

chemistry
For the reaction 2A(g) + B(aq) + 3C(l)<------> D(s) + 3E(g), the concentrations at equilibrium are found to be: A: 2.3x10^3 Pa B: 1.8x10^-2 M C: 15.8M D: 12.5M E: 5.6x10^4 Torr Find the numerical value of the equilibrium constant that would appear in a conventional table...
Sunday, March 10, 2013 at 7:20pm

chemistry
H2(g) + I2(g) *) 2HI(g) + heat Which response includes all the following that will shift the equilibrium to the left, and no others?
Sunday, March 10, 2013 at 6:37pm

chemistry
H2(g) + I2(g) *) 2HI(g) + heat Which response includes all the following that will shift the equilibrium to the left, and no others?
Sunday, March 10, 2013 at 6:37pm

chemistry
The formula weight of an acid is 82. In a titration, 100cm3 of the solution of this acid containing 39g of this acid per litre were completely neutralized by 95 cm3 of aqueous naoh containing 40g of naoh per litre. What is the basicity of this acid? Bob helps me
Sunday, March 10, 2013 at 4:46pm

Chemistry
Phosphoric acid, H3PO4(aq), is a triprotic acid, meaning that one molecule of the acid has three acidic protons. Estimate the pH, and the concentrations of all species in a 0.300 M phosphoric acid solution. kPa1: 2.16 kPa2: 7.21 kPa3:12.32 [H3PO4] = ? [H2PO4-] = ? [HPO42...
Sunday, March 10, 2013 at 2:47pm

college general chemistry
3Co(NO 3 ) 2 (aq) + 2Na 3 PO 4 (aq) &---> Co 3 (PO 4 ) 2 (s) + 6NaNO 3 (aq) how do I find the molar mass of precipitate.X hydrate
Sunday, March 10, 2013 at 1:48pm

Chemistry
How will the addition of sodium acetate to an acetic acid solution affect the pH? A. solution becomes hotter B. It will lower the pH C. It will raise the pH D. pH will not change E. pH cannot be measured I selected answer D and got it wrong. I don't understand why...
Sunday, March 10, 2013 at 12:18pm

chemistry
a solution (S) is prepared by dissolving 50.0 g calcium chloride in 250 ml volumetric flask wich is then filled with distilled water up to the line mark. calculate the molar concentration of solution (S)
Sunday, March 10, 2013 at 9:11am

chemistry help !!!!!!!!!!!!!!!!
a)A N6+ ion in its ground state absorbs an X-ray photon of energy 2.0000 keV. Explain what happens to the ion and why. b)Explain why the nitrogen ion N6+ is a hydrogen-like ion. Assuming the ion is for the major stable isotope 14N, state which sub-atomic particles it contains ...
Sunday, March 10, 2013 at 9:05am

chemistry
Plastic articles can be chromium-plated by coating them with thin layer of graphite paste,placing them in a bath of aqueous chromium(III) sulphate and electroplating. a)Suggest a reason why the article is first coated with graphite. b)what substance could be used for the other...
Sunday, March 10, 2013 at 6:39am

chemistry
What volume of oxygen is consumed when 9g of water is formed when butane is burnt?
Sunday, March 10, 2013 at 5:28am

chemistry
The equilibrium bond length of 1 H35Cl is 126 pm. What is wavelength of the required electromagnetic radiation to excite the rotational state from j=1 to j=2? The masses of 1H and 35Cl are 1.0078 amu and 34.9689 amu, respectively)
Sunday, March 10, 2013 at 4:52am

chemistry
the maximum volume if Ziploc sandwich is 0.5 L at the pressure of 1 atm. use the gas law, calculate the pressure in the bag from the above volume of co2.
Sunday, March 10, 2013 at 4:42am

chemistry
7750 Joules of energy is added to a 325 grams stone at 24.0 degrees centigrade. The temperature increases by 75.0 degrees centigrade. What is the specific heat of the stone?
Sunday, March 10, 2013 at 4:22am

chemistry
7750 Joules of energy is added to a 325 grams stone at 24.0 degrees centigrade. The temperature increases by 75.0 degrees centigrade. What is the specific heat of the stone?
Sunday, March 10, 2013 at 4:21am

chemistry
7750 Joules of energy is added to a 325 grams stone at 24.0 degrees centigrade. The temperature increases by 75.0 degrees centigrade. What is the specific heat of the stone?
Sunday, March 10, 2013 at 4:17am

Chemistry
Which of the following represent conjugate acid-base pairs? For those pairs that are not conjugates, write the correct conjugate acid or base for each species in the pair. a. HS-4-,SO4^2- B. HBr, BrO- c. H2PO4-, PO4^3- d. HNO3, NO2-
Sunday, March 10, 2013 at 3:26am

Chemistry
use the bronsted-lowry model to label the acid-base pairs in the following equation for the ionization of water: H20(L) + H20(L) <--> H30+(AQ) + OH-(AQ). EXAPLAIN
Sunday, March 10, 2013 at 3:23am

chemistry
what are structural examples of an aldehyde?
Saturday, March 9, 2013 at 10:59pm

chemistry
Sn (s) + 2Cl2(g) --> SnCl4(l).Sn(s) + Cl2(g) --> Sn Cl2(l) DH = -186.2 kJSnCl2(s) + Cl2(g) --> SnCl4(l) DH = -325.1 kJWhat is the change in enthalpy?
Saturday, March 9, 2013 at 10:39pm

chemistry
Is CF4 polar or nonpolar?
Saturday, March 9, 2013 at 10:16pm

Chemistry
How many grams of Na3PO4 are needed to produce 250mL solution that has an Na concentration of 1.04M?
Saturday, March 9, 2013 at 9:15pm

chemistry
How many grams of Na2CO3 should be mixed with 50.00g of NaHCO3 to produce 2000mL of buffer with pH=10?
Saturday, March 9, 2013 at 8:29pm

what is the activity coefficient of SO4^2- when the ionic strength of a solution is .1?
Saturday, March 9, 2013 at 6:23pm

chemistry pH
calculate [H^+] and the pH of 0.025M of HNO3
Saturday, March 9, 2013 at 6:02pm

chemistry
the molar mass of NaOH is 40g/mol, how many grams ofNaOH are required to yield 0.65 mol?
Saturday, March 9, 2013 at 5:56pm

Chemistry
A 0.464 gram sample of a metal, M, reacts completely with sulfuric acid according to: M(s) +H2SO4(aq)=MSO4(aq)+H2(g) A volume of 211 mL of hydrogen is collected over water; the water level in the collecting vessel is the same as the outside level. Atmospheric pressure is 756.0...
Saturday, March 9, 2013 at 5:39pm

chemistry
Find the concentration of Ag^+ in a saturated solution of AgBrO_3_ that also contains 0.02M LiNO_3_, .02M KClO_4_ and .01M NaF
Saturday, March 9, 2013 at 5:04pm

chemistry
find the concentrations of Ca^2+ and F^- in a saturated solution of CaF_2_
Saturday, March 9, 2013 at 5:03pm

chemistry
find the concentration of Pb^2+ in equilibrium with PbBr_2_ and 0.10M Br^-
Saturday, March 9, 2013 at 5:01pm

chemistry
name of the following compound: ch2-ch3 / ch3-ch2-ch-ch2-ch2-ch=ch-ch3
Saturday, March 9, 2013 at 3:03pm

chemistry
How many electrons in a cesium atom can have the quantum numbers of n = 3 and ml = -1
Saturday, March 9, 2013 at 1:01pm

Chemistry
In a 1.0× 10–4 M solution of HClO(aq), identify the relative molar amounts of these species. (most to least) H2O HClO H3O OH- OCl-
Saturday, March 9, 2013 at 11:52am

Chemistry
Phosphoric acid, H3PO4(aq), is a triprotic acid, meaning that one molecule of the acid has three acidic protons. Estimate the pH, and the concentrations of all species in a 0.300 M phosphoric acid solution. pKa1: 2.16 pKa2: 7.21 pKa3: 12.32 Hint: Convert the pKa values to Ka ...
Saturday, March 9, 2013 at 11:26am

Chemistry
NH3 is a weak base (Kb = 1.8 × 10–5) and so the salt NH4Cl acts as a weak acid. What is the pH of a solution that is 0.050 M in NH4Cl?
Saturday, March 9, 2013 at 11:08am

Chemistry
1.55 g of penatanol 250ml water Heat from 10 to 38 degrees Find hear of combustion
Saturday, March 9, 2013 at 8:27am

Chemistry 104
A reaction rate doubles when the temperature increases from 0 degrees Celsius to 10 degrees Celsius, maintaining everything else equal. What is the activation energy for this reaction? (R = 8.314 J/mol K)
Friday, March 8, 2013 at 11:18pm

Chemistry 104
A reaction rate doubles when the temperature increases from 0 degrees Celsius to 10 degrees Celsius, maintaining everything else equal. What is the activation energy for this reaction? (R = 8.314 J/mol K)
Friday, March 8, 2013 at 11:16pm

Chemistry
At a certain temperature, the equilibrium constant, Kc, for this reaction is 53.3. H2(g)+I2(g) <--> 2HI(g) Kc= 53.3 At this temperature, 0.300 mol of H2 and 0.300 mol of I2 were placed in a 1.00-L container to react. What concentration of HI is present at equilibrium? HI...
Friday, March 8, 2013 at 10:38pm

Chemistry
At a certain temperature, 0.900 mol of SO3 is placed in a 2.00-L container. 2SO3(g)<--> 2SO2(g)+O2(g) At equilibrium, 0.130 mol of O2 is present. Calculate Kc. Kc= ? Please post the answer if possible or the steps in detail; I have attempted this problem many times and ...
Friday, March 8, 2013 at 10:35pm

Chemistry Problem
At 25 oC, Kc = 0.145 for the following reaction in the solvent CCl4. 2BrCl <----> Br2 + Cl2 A solution was prepared with the following initial concentrations: [BrCl] = 0.0482 M, [Br2]= 0.0307 M, and [Cl2]= 0.0277 M. What will their equilibrium concentrations be? How do i...
Friday, March 8, 2013 at 10:29pm

Chemistry
Phosphorus pentachloride decomposes according to the chemical equation: PCl5(g)<--> PCl3(g)+Cl2(g) Kc = 1.80 at 250 degrees Celsius A 0.352 mol sample of PCl5(g) is injected into an empty 4.45 L reaction vessel held at 250 °C. Calculate the concentrations of PCl5(g) ...
Friday, March 8, 2013 at 10:16pm

Chemistry
If you start with 200 ml of 0.1M HEPES buffer (pH 7.5) and add 1.25 ml of 0.5M HCl, what will the final pH be? (The pKa of HEPES is 7.5)
Friday, March 8, 2013 at 6:26pm

General Chemistry
At a certain temperature, the equilibrium constant for the following chemical equation is 2.90. At this temperature, calculate the number of moles of NO2(g) that must be added to 2.53 mol of SO2(g) in order to form 1.10 mol of SO3(g) at equilibrium. SO2(g)+ NO2(g) <> SO3...
Friday, March 8, 2013 at 5:23pm

Chemistry
!00.0 grams of Na2SO4 reacts with 150.00 grams of Ba(NO3)2to form NaNO3 and BaSO4. How many grams of barium sulfate will form?
Friday, March 8, 2013 at 12:47pm

chemistry
what is the molarity of a sodium hydroxide solution if 26.0mL of the solution os titrated to the end point with 57.5mL of a 0.500M hydrochloric acid solution
Friday, March 8, 2013 at 11:50am

Chemistry
An experiment requires 0.7 M NH3(aq). The stockroom manager estimates that 15 L of the base is needed. What volume of 15 M NH3(aq) will be used to prepare this amount of 0.7 M base?
Friday, March 8, 2013 at 10:38am

chemistry
how many grams of H2O will be produced if 65.8 grams of CH3OH completely reacts?
Friday, March 8, 2013 at 9:58am

Chemistry
What volume of ethanol must be diluted with water to prepare 768 mL of 0.873 M solution? The density of ethanol is given as 0.789 g/mL. Answer in units of mL
Friday, March 8, 2013 at 12:49am

Chemistry
(ii) between 0 and 100.0 mL NaOH added H2A H2O HA - Na+ A2- OH - (iii) 100.0 mL NaOH added H2A H2O HA - Na+ A2- OH - (iv) between 100.0 mL and 200.0 mL NaOH added H2A H2O HA - Na+ A2- OH - (v) 200.0 mL NaOH added H2A H2O HA - Na+ A2- OH - (vi) after 200.0 mL NaOH added H2A H2O...
Friday, March 8, 2013 at 12:13am

Chemistry
calculate the standard free-energy change for the synthesis of hydrazine from nitrogen and hydrogen. N2(g) + H2(g) right arrow N2H4(l)
Thursday, March 7, 2013 at 11:22pm

chemistry
a current of .500 A is used for the electrolytic decomposition of water. how long (in hours) will it take to produce 1.0 L (Standard temperature and pressure) of hydrogen gas? what mass of oxygen gas will be produced at the same time?
Thursday, March 7, 2013 at 11:07pm

Chemistry
What is the volume of 0.674 kg of acetylene, C2H2, at STP?
Thursday, March 7, 2013 at 10:39pm

Chemistry
When a diprotic acid, H2A, is titrated by NaOH, the protons on the diprotic acid are generally removed one at a time, resulting in a pH curve that has the following generic shape. (a) Notice that the plot has essentially two titration curves. If the first equivalence point ...
Thursday, March 7, 2013 at 9:57pm

Chemistry
Find the pH and volume (mL) of 0.447 M HNO3 needed to reach the equivalence point(s) in titrations of each of the following. (a) 2.65 L of 0.0950 M pyridine (C5H5N) pH volume Answer = 563 mL (b) 0.188 L of 0.250 M NH3 pH volume Answer = 105 mL I can't figure out the pHs ...
Thursday, March 7, 2013 at 9:53pm

Chemistry
Recall that all aqueoous solutions contain_____. Water can also undergo ____. This process is called the ______of water. The reaction can be written as: Notice the double arrow in the reaction. This indicates that the reaction is_____. However, only a tiny fraction of water ...
Thursday, March 7, 2013 at 9:53pm

Chemistry
Oxidation of bis(bipyridine) copper (I) ion by molecular oxygen is described by the equation: Cu(C10H8N2)2+(aq) + O2(aq) ----products The reaction is first order in oxygen and second order in Cu(C10H8N2)2+ (a) Write the rate law (b) What is the overall reaction order? (c) How ...
Thursday, March 7, 2013 at 9:36pm

Chemistry
These blanks I REALLLY need your help. Our teacher gave the teaching job to this other I think coop student who wants to be a teacher to teach for a day but I| seriously don't understand anything she said..in short I don't have anyyy clue about this. So please help me...
Thursday, March 7, 2013 at 9:08pm

How many milligrams of sodium azide will produce 8.35 Liters of N2 at STP???
Thursday, March 7, 2013 at 9:05pm

Science- chemistry
fuzzy silver coating is impure silver. it can be converted back into silver nitrate by reacting it with nitric acid what has been done to the reaction mixture to recover solid silver nitrate?
Thursday, March 7, 2013 at 8:54pm

chemistry
2NaOH + H2SO4 yields Na2SO4+2H2O calculate the molarity of H2SO4
Thursday, March 7, 2013 at 8:11pm

Chemistry
A 50.0 mL sample of 0.10 M pyridine, C5H5N, is titrated with 0.2 M HBr. Calculate the pH to one decimal place when the following volumes of titrant have been added. 0.00 mL a) 0ml b)17ml c)25ml d)40ml
Thursday, March 7, 2013 at 8:03pm

chemistry
A buffer consists of 0.14 M KHCO3 and 0.61 M K2CO3. Carbonic acid is a dirpotic acid with Ka1= 4.5*10^-7 and Ka2= 4.7*10^-11. a) which Ka value is more important to this buffer b) what is the buffer pH?
Thursday, March 7, 2013 at 7:53pm

chemistry
copper compounds such as copper (II) sulfate are toxic. before disposal, these compounds must be treated to reduce their toxicity. describe how to use steel wool to remove the Cu 2+ ions from an aqueous solution of copper (II) sulfate
Thursday, March 7, 2013 at 7:27pm

Chemistry
What is the pH of a 0.77M solution of methylamin at 25 degree C? CH3NH2, Kb= 4.4X10-4? How do I set this up to get the answer?
Thursday, March 7, 2013 at 7:19pm

chemistry
Calculate the pH of a 195 mL solution containing 7.50g of ethylamine (CH3CH2NH2) and 7.50g of ethylammonium bromide (CH3CH2NH3+ Br-). The Kb of ethylamine is 4.7 x 10-4
Thursday, March 7, 2013 at 6:44pm

math
A textbook store sold a combined total of 315 physics and chemistry textbooks in a week. The number of physics textbooks sold was two times the number of chemistry textbooks sold. How many textbooks of each type were sold?
Thursday, March 7, 2013 at 5:44pm

chemistry
When magnesium burns in air, it reacts with oxygen and nitrogen, forming magnesium oxide and magnesium nitride. If 20.0L of air is available for this reaction, what mass of each compound can be formed? (Remember air is about 80% Nitrogen and 20% Oxygen)
Thursday, March 7, 2013 at 5:42pm

Chemistry
If some NH4Cl is added to an aqeous solution of NH3: A. pH of solution will decrease B. PH will not change C. pH will increase D. NH4Cl cannot be added to NH3 E. The solution will not have pH I think the answer is B, because if NH4Cl is added to the solution of NH3, then ...
Thursday, March 7, 2013 at 5:38pm

chemistry
What molar ratio of acetic acid to sodium acetate is required to create a buffer solution at a pH of 4.89 at 25 degree C? Ka for acetic acid is 1.8 X 10-5 A. 2.9 B.0.56 C.1.4 D.0.72 E.0.2 ( I chose this and got is wrong) I'm lost on how to do these problems, but I started ...
Thursday, March 7, 2013 at 5:35pm

chemistry
For each of the following reactions, predict whether the equilibrium lies predominantly to the left or to the right. HCN(aq) + SO42-(aq) CN -(aq) + HSO4-(aq) I think it has something to do with the Ka but im not sure!
Thursday, March 7, 2013 at 4:57pm

chemistry
When 5.00 grams of copper racts with excess silver nitrate, silver metls and sopper nitrate are produced. What is the theoretical yeild of silver in this reaction? please give step by step help
Thursday, March 7, 2013 at 4:54pm

Chemistry
What will happen if a small amount of hydrochloric acid is added to a 0.1 M solution of HF? A) The percent ionization of HF will increase. B) The percent ionization of HF will decrease. C) The percent ionization of HF will remain unchanged. D) Ka for HF will increase. E) Ka ...
Thursday, March 7, 2013 at 4:48pm

Chemistry
Calculate the pH of a solution created by adding 5.00g of LiF to 150.0mL of 1.25M HF. Ka = 7.2 x 10-4
Thursday, March 7, 2013 at 4:39pm

Chemistry
Determine the boiling point of a solution contanting 36.1grams calcium chloride molar mass 112 in 200.0grams water.
Thursday, March 7, 2013 at 1:54pm

Chemistry
The molal freezing point constant(Kf) for acetic acid is 3.90 C/m. When 31.5 grams of unknown solute is dissolved in 650 grams of acid the freezing point is lowered by 0.79 what is the molar mass
Thursday, March 7, 2013 at 1:48pm

Chemistry
Please explain this, I have no idea how to figure this out. What molecule or polyatomic ion has the following features. (a) four bonded atoms, no unshared electrons on the central atom (b) two bonded atoms, no unshared electrons on the central atom (c) two bonded atoms, one ...
Thursday, March 7, 2013 at 1:46pm

Chemistry
How many grams of NH4Br(Molar Mass=98g)are in 440.0 mL of 1.75Moles NH4Br
Thursday, March 7, 2013 at 1:41pm

Chemistry
You are using concentrated hydrochloric acid solution (12.0 M)to make 445.0 ml of a 5.85 M solution. Calculate the number of milliliters of concentrated HCl required to make the solution.
Thursday, March 7, 2013 at 1:22pm

Chemistry
The density of carbon in the form of diamonds is 3.51 g/cm^3. If you have a 40- carat spherical diamond, what is the diameter of the diamond in millimeters? (1 carat=0.200 g)
Thursday, March 7, 2013 at 12:54pm

chemistry
which alkali metal form superoxidess?(2)explain why rubidium has a short life?
Thursday, March 7, 2013 at 12:10pm

chemistry
explain why iron is paramagnetic?
Thursday, March 7, 2013 at 12:06pm

Chemistry
A Serum taken from a patient being treated with lithium for manic-depressive illness was analyzed for lithium concentration. A reading of 291 units was obtained for the intensity of the 671 nm red emission line. Then 1.00 mL of a 11.7 mM Lithium standard was added to 9.00 mL ...
Thursday, March 7, 2013 at 11:19am

plus 1-chemistry
calculate the mass of caco3 required to librate 10l of co2 at stp?
Thursday, March 7, 2013 at 11:10am

chemistry
how do i balance SO3 + H2O = H2SO4
Thursday, March 7, 2013 at 10:53am

Chemistry
Describe an experimental method for the estimation of oxalate in the product, potassium trioxalatoaluminate(III)
Thursday, March 7, 2013 at 9:59am

Chemistry
Given the part of the molecule shown below, can the red atom participate in a hydrogen bond with an approriate bonding partner? -O-H -C-H -N-H -O-H -C-H -N-H
Thursday, March 7, 2013 at 9:42am

Chemistry
Given these pairs of atoms, indicate whether the following bonds are polar or non-polar covalent bonds. C-H N-H O-H C-C
Thursday, March 7, 2013 at 9:39am

chemistry
A gas with the smell of rotten eggs is evolved with dilute sulphuric acid is added to a simple of salt.the gas evolved could turn?
Thursday, March 7, 2013 at 9:36am

chemistry
the reaction between H2 and O2 reaches equilibrium in a closed container according to the following balanced equation: 4HCl+O2=2H2O+2Cl2 the volume of the container is 5dm3 calculate the equilibrium constant (Kc) for this reactin
Thursday, March 7, 2013 at 8:53am

Chemistry
Mercury dissolves in concentrated nitric acid, with the evolution of a reddish-brown gas, just as in the reaction shown in figure 5.4 on page 188 for copper. The oxidation state of the mercury after reaction is +2. Write a balanced net ionic equation for the reaction?
Thursday, March 7, 2013 at 7:50am

Chemistry
A 1.00 kg gold bar at 1010 K is dropped into 0.750 kg of sand at 25 °C. Assuming no heat is lost to the atmosphere, what is the final temperature of the sand?
Thursday, March 7, 2013 at 2:59am

Chemistry
A 1.00 kg gold bar at 1010 K is dropped into 0.750 kg of sand at 25 °C. Assuming no heat is lost to the atmosphere, what is the final temperature of the sand?
Thursday, March 7, 2013 at 2:52am

chemistry
20cm3 of saturated aqueous solution of hydrogen carbonate (iv) at 25^oc requires 10cm3 of 2.0moldm-3 hydrochloric acid for complete reaction.what is the solubility of sodium hydrogen carbonate(iv) in moldm-3 at 25^oc
Thursday, March 7, 2013 at 1:45am

general chemistry
Calculate the molarity of each of the following solutions. 12.03mg KI in 107.6mL of solution.Express your answer using four significant figures.
Thursday, March 7, 2013 at 1:40am

Chemistry
For each of the following, enter the number of covalent bonds that the atom can form: (A) One atom of carbon (B) One atom of sulfur (C) One atom of nitrogen with no net charge (D) One atom of nitrogen with positive net charge (E) One atom of oxygen with no net charge (F) One ...
Thursday, March 7, 2013 at 1:31am

general chemistry
Calculate the molarity of each of the following solutions.70.8g C2H60 in 2.51L of solution
Thursday, March 7, 2013 at 1:28am

Chemistry
Mercury dissolves in concentrated nitric acid, with the evolution of a reddish-brown gas, just as in the reaction shown in figure 5.4 on page 188 for copper. The oxidation state of the mercury after reaction is +2. Write a balanced net ionic equation for the reaction?
Thursday, March 7, 2013 at 1:08am

general chemistry
Calculate the molarity of each of the following solutions.70.8 in 2.51 of solution
Thursday, March 7, 2013 at 1:07am

chemistry
what is equillibrium?
Thursday, March 7, 2013 at 12:51am

Chemistry
if in a solution the [H+]= 1x10-5M, then the [OH-] equals the same. true or false
Thursday, March 7, 2013 at 12:42am

chemistry
A nitric acid solution of unknown concentration is used to titrate 0.771g of sodium tyrosinate (NaC9H10NO3). If the endpoint is reached when 32.79mL of nitric acid has been added, what is the concentration of the unknown nitric acid solution?
Wednesday, March 6, 2013 at 11:51pm

Chemistry
Why is why is CH4+2O2 --> CO2+2H2O very slow at room temperature?
Wednesday, March 6, 2013 at 8:56pm

Chemistry
(1)Aluminum reacts with oxygen to produce aluminum oxide according to the following reaction: 4Al(s) + 3O2(g) → 2Al2O3(s) Calculate the moles of Al2O3 produced when the reaction is performed with 31.06 g of each reactant. (2)Nitrogen dioxide reacts with water to produce ...
Wednesday, March 6, 2013 at 8:54pm

Chemistry
You have 10.0 L of 1.2 M KNO3. What molarity would the KNO3 solution be if you were to take 2.5 L of it and dilute it to 10.0 L?
Wednesday, March 6, 2013 at 8:54pm

chemistry
What is the pH of pure water in equilibrium with 1 atmosphere of carbon dioxide at 25˚C? (Hint, what does 1 atmosphere of CO2 mean?)
Wednesday, March 6, 2013 at 8:31pm

ap chemistry
If 310mL of 2.2molar HCl solution is added to 135 mL of 3.6 molar Ba(OH)2 solution, what will be the molarity of BaCl2 in the resulting solution? Answer in units of M
Wednesday, March 6, 2013 at 5:56pm

Chemistry
Stuck on this because I haven't done chemistry in a while. Can someone guide me through it or help me out? Balance the reduction-oxidation chemical equation in base: MnO4- + HSO3- -> MnO2 + SO4^ 2-
Wednesday, March 6, 2013 at 5:31pm

Chemistry
How many mols of OH-(aq) ions are present in 20.33mL of 1.33M sodium hydroxide solution?
Wednesday, March 6, 2013 at 5:20pm

Chemistry
How many mols of tyrosinate ions (C9H10NO3-(aq)) are present in 909mg of sodium tyrosinate solid (NaC9H10NO3)?
Wednesday, March 6, 2013 at 5:20pm

Chemistry
In the reaction Fe^2O^3+3CO->2FE+3CO^2, what is the total number of moles of CO used to produce 112 grams of iron? Please explain step by step how to do this problem, thanks:)
Wednesday, March 6, 2013 at 5:09pm

chemistry
Calculate the hydronium ion concentration and pH in a 0.037 M solution of sodium formate, NaHCO2. hydronium ion concentration i dont understand these
Wednesday, March 6, 2013 at 5:01pm

chemistry
Calculate the percent recovery of copper if: 7.26 g is the initial amount and 8.61 g is the amount recovered?
Wednesday, March 6, 2013 at 4:13pm

chemistry
The system H2 (g) + 3N2 (g) = NH3 (s) is at equilibrium.Use Le Chatelier's principle to predict the direction in which the equilibrium will shift if the ammonia is withdrawn from the reaction chamber.
Wednesday, March 6, 2013 at 12:31pm

chemistry
If the temperature of the system PCl5 (g) =PCl3 (s) + Cl2 (g) + 92.5 kj. is increased, predict the direction of th Le Chatelier's shift.
Wednesday, March 6, 2013 at 12:26pm

chemistry
The volume occupied by the reaction SiF4(g)+2H2O (g)=SiO2 (s)+4HF (g). is reduced.Predict the direction of shift in the position of equilibrium.Will the shift be in the direction of the more gaseous molecules,or fewer?
Wednesday, March 6, 2013 at 12:22pm

Chemistry
If 15gram of potassium trioxochlorate V is heate in MnO2.What is the mass of chloride produce
Wednesday, March 6, 2013 at 5:06am

Chemistry
If 15gram of potassium trioxochlorate V is heated in the presence of MnO2.What is the mass of chloride produce?
Wednesday, March 6, 2013 at 4:51am

Chemistry
If 15gram of potassium trioxochlorate V is heated in the presence of MnO2.What is the mass of chloride produce?
Wednesday, March 6, 2013 at 4:51am

Analytical Chemistry
How many milliliters of 0.202 M KOH should be added to 500.0 mL of 0.0233 M tartaric acid (C4H6O6; FW 150.087) to adjust the pH to 2.75? Ka1 = 1.0 x 10-13 and Ka2 = 4.6 x10-5. I ended up with KOH mL being about 1.5mL. The equiv. point would be around 57mL. I see the answer is ...
Wednesday, March 6, 2013 at 1:33am

Chemistry
Given the following chemical reaction what is the bond enthalpy of OH 4NH3 3O2 yields 2N2 6H20 Change H 1266 kJ NH equals 389 O O equals 498 and N N equals 941 3
Wednesday, March 6, 2013 at 1:19am

chemistry
how many grams of h2 are required to produce 11/4000
Wednesday, March 6, 2013 at 1:02am

chemistry
what is the pH of a solution that has 12.2 grams of hydrochloric acid in 500 ml of water
Tuesday, March 5, 2013 at 10:48pm

Chemistry
The decomposition of hydrogen peroxide is first order in H2O2: 2H2O2(aq) → 2H2O(l) + O2(g) Rate = k [H2O2] How long will it take for half of the H2O2 in a 10-gal sample to be consumed if the rate constant for this reaction is 5.6 x 10-2 s-1?
Tuesday, March 5, 2013 at 10:12pm

Chemistry
is Fe3O4 + 4H2 = 3Fe + 4H2O spontaneous at 298 K? Delta H system= 149.8 kj/mol Delta S system= 610.0 kj/mol
Tuesday, March 5, 2013 at 9:18pm

Chemistry
I've figured out most of it. I'm not sure how to find the percentage ofd the isotope. Define the half life. The half-life of a radioisotope is found to be 4.55 minutes. If the decay follows first order kinetics, what percentage of isotope will remain after 2.00 hours ...
Tuesday, March 5, 2013 at 8:57pm

Chemistry
I've figured out the Ea but I'm not sure how to find the kcal/mol The gas reaction N2O5 → 2NO2 + 1/2O2 follows the Arrhenius equation k = Ae(-Ea/RT) where R = 8.314 J K-1 mol-1 and 1 calorie = 4.184J. At the temperature T=273K, k = 3.46 x 10-5 s-1, whereas at T...
Tuesday, March 5, 2013 at 8:56pm

Chemistry
. For the reaction 2H2(g) + 2NO(g) → N2(g) + 2H2O(g) The observed rate law is Rate =k[NO]2[H2] The mechanisms shown below have been proposed to explain the kinetics of the above reaction Which of the following are acceptable mechanisms? Explain you answer Mechanism I 2H2...
Tuesday, March 5, 2013 at 8:47pm

Chemistry
I've tried to answer some -The reaction mechanism for a reaction is as follows… Step 1 O3 (g) + NO2 (g)→ NO3 (g) + O2 (g) slow Step 2 NO3 (g) + NO2 (g) → N2O5 (g) fast a. Write the overall reaction equation. b. Identify the molecularity of each step. They ...
Tuesday, March 5, 2013 at 8:46pm

Chemistry
Given…Overall reaction: 2 NO2 (g) + F2 (g) → 2 NO2F (g) Rate = k[NO2][F2] a. Can this be a single step reaction? b. Postulate a mechanism using experimental data and chemical intuition come up with a mechanism that fits.
Tuesday, March 5, 2013 at 8:45pm

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