Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

chemistry
If 3.12 kg of S are reacted with oxygen calculate the volume of SO2 gas in mL formed at 35 degrees Celsius and 1.09 atm
Sunday, March 24, 2013 at 11:09pm

Chemistry
The minimum frequency of light needed to eject electrons from a metal is called the threshold frequency, ν0. Find the minimum energy needed to eject electrons from a metal with a threshold frequency of 5.48 × 1014 s–1. With what kinetic energy will electrons be...
Sunday, March 24, 2013 at 10:57pm

Chemistry
Assuming that the smallest measurable wavelength in an experiment is 0.410 fm (femtometers), what is the maximum mass of an object traveling at 395 m·s–1 for which the de Broglie wavelength is observable?
Sunday, March 24, 2013 at 10:52pm

general chemistry
What is the radius of the largest sphere that can be placed at the center of a face-centered cubic unit cell of a cubic closest-packed array of spheres if the spheres have radius of 2.0 x 10^2 pm?
Sunday, March 24, 2013 at 10:51pm

general chemistry
KCl crystallizes in a structure like NaCl. The ionic radius of Na+ is 0.525 times the ionic radius of Cl^- and 0.714 times the ionic radius of K+. What is the ratio of the density of NaCl to that of KCl?
Sunday, March 24, 2013 at 10:34pm

Chemistry
calculate the volume of 0.50 M NaOH needed to saturate 100.0 ml of 0.50 M Zn(NO3)2 with Zn(OH)2
Sunday, March 24, 2013 at 9:29pm

Chemistry
K1 = 0.727 K2 = 12.1 T1 = 2000 T2 = 3000 Solve for the standard enthalpy of formation. They gave me the formula ln(K2/K1) = DeltaH /R (T2 - T1 / T1T2) The answer is supposed to be in KJ/mol and I keep getting 2.022 but its not right. I'm not sure what Im doing wrong
Sunday, March 24, 2013 at 8:17pm

chemistry (Pls Bob check for me)
A 0.5g of fuming h2so4 oleum is diluted with water. This solution is completedly neutralized by 26.7ml of 0.4N naoh. Find the percentage of free so3 in the sample The asnwer 20.6% My calculation h2so4= 98/2 = 49 so3= 80/2 = 40 26.7ml x 0.4N = 10.68ml - 0.01068L x/49 + x/40 (0....
Sunday, March 24, 2013 at 7:39pm

Chemistry
A solution is prepared by dissolving 571.6 g of H 2SO4 in enough water to make 1000.0 mL of solution. The solution has a density of 1.3294 g/mL. (molar mass of H2SO4 = 98.08). What is the molar concentration of the solution?
Sunday, March 24, 2013 at 7:33pm

Chemistry
What do we mean when we say that concentrated nitric acid (HNO3) is 16 molar?
Sunday, March 24, 2013 at 7:15pm

Chemistry
Calculate both the moles and grams in each of the following? a. 6.02 x 10^23 atoms of Na e. 3.01 x 10^23 atoms of S
Sunday, March 24, 2013 at 7:12pm

Math
For a chemistry experiment, Heather needs 3.75 grams of salt. How many decigrams of salt does Heather need?
Sunday, March 24, 2013 at 6:40pm

Chemistry (Immunoassays)
What is the common component that makes a homogeneous competitive immunoassay? Describe one.
Sunday, March 24, 2013 at 6:30pm

Chemistry!!!!!! Please help immediately!!!
Please show me step by step. Thank you. One commercial method used to peel potatoes is to soak them in a solution of NaOH for a short time, remove them from the NaOH, and spray off the peel. The concentration of NaOH is normally in the range of 3 to 6 M. The NaOH is analyzed ...
Sunday, March 24, 2013 at 6:21pm

Chemistry
The Ka of a monoprotic weak acid is 8.11 x 10 ^ -3. What is the percent ionization of a 0.125M solution of this acid?
Sunday, March 24, 2013 at 6:14pm

chemistry
At a certain temperature, the concentrations of NO and NH3 are equal, and the concentration of H2o and o2 are 2.0M and 3.0M respectively. What is the value of Keq at this temp? The equation is 5O2+4NH3--> 4NO+6H20
Sunday, March 24, 2013 at 6:10pm

statistics
The grades on the final examination given in a large organic chemistry class are normally distributed with a mean of 72 and a standard deviation of 8. The instructor of this class wants to assign an “A” grade to the top 10% of the scores, a “B” grade to the...
Sunday, March 24, 2013 at 5:22pm

Chemistry
A solution is prepared by dissolving 0.12 mol of acetic acid and 0.12 mol of ammonium chloride in enough water to make 1.0 L of solution. Find the concentration of ammonia in the solution.
Sunday, March 24, 2013 at 4:26pm

Chemistry
One reaction of iron with hydrochloric acid is represented by the following thermochemical equation. Fe(s) + 2HCl(aq) ? FeCl2(aq) + H2(g); (Delta)H°= –87.9 kJ How much heat is liberated at constant pressure if 0.215 g of iron reacts with 40.4 mL of 0.579 M HCl? How ...
Sunday, March 24, 2013 at 3:36pm

Chemistry
Na2CO3 reacts with H2SO4 to give respective salt water and carbon dioxide. Calculate the mass of pure salt formed when 300 g of Na2CO3 of 80% purity reacts with H2SO4
Sunday, March 24, 2013 at 2:46pm

Chemistry
A 5.0 mL sample of HCl is placed in a flask. Titration required 15.0 mL of .20 M NaOH. What is the molarity of the HCl in the sample?
Sunday, March 24, 2013 at 12:32pm

chemistry 2 college
explain how to find the mass of solute in the solution: 50.0g of solvent in a 10.0% NaCl solution?
Sunday, March 24, 2013 at 12:25pm

chemistry
what is the total heat lost if you have 8 grams of copper and the temperature changed from 43°C to 36°C
Sunday, March 24, 2013 at 12:02pm

Chemistry
Calculate the pressure of 0.800 moles of helium gas, when the gas is in a balloon with a volume of 2.30 L at a temperature of 32°C.
Sunday, March 24, 2013 at 11:32am

Chemistry
I do not understand the acid + base ->conjugate base + conjugate acid Please explain it to me with an example. I really do not understand it and I truly need your help. I do not understand how he hydrogens transfer and stuff like that. Your help is very much appreciated! ...
Sunday, March 24, 2013 at 9:35am

Chemistry
Ethyl alcohol which is prent in many beverages molecular formular C2H6O.If 9.2g of ethyl alcohol are available.Calculate number of molecular of ethyl alcohol 9.2g of ethyl alcohol.
Sunday, March 24, 2013 at 4:14am

Chemistry
• Describe the properties of acids and bases and explain the concept of pH • How will you measure the pH of the soil in your garden • How will pH affect materials and equipment you might use in gardening. • 3 vegetables and 3 flowers that would work well ...
Sunday, March 24, 2013 at 3:47am

chemistry
How many grams are in 4.00mol of sodium chloride (\rm NaCl)
Sunday, March 24, 2013 at 3:10am

chemistry
Tantalum metal is produced by reaction of potassium heptafluorotantalate (K2TaF7) with elemental sodium (Na) in a reactor heated to 850oC. The by-products are potassium fluoride (KF) and sodium fluoride (NaF). The reactor is charged with 244.0 kg of K2TaF7 and 13.0 kg of Na. ...
Sunday, March 24, 2013 at 1:30am

chemistry
What fraction of piperazine (perhydro-1,4-diazine) is in each of its three forms (H2A, HA–, A2–) at pH 8.98?
Saturday, March 23, 2013 at 11:36pm

chemistry
Determine [Zn2 ], [CN–], and [HCN] in a saturated solution of Zn(CN)2 with a fixed pH of 1.78. The Ksp for Zn(CN)2 is 3.0 × 10–16. The Ka for HCN is 6.2 × 10–10.
Saturday, March 23, 2013 at 11:00pm

chemistry
.592grams of na2so4
Saturday, March 23, 2013 at 7:43pm

chemistry
if you want a solution that is .1m in ions what mass of na2so4 must you dissolve in125 grams of water assume total dissolution of ionic solid.
Saturday, March 23, 2013 at 7:23pm

CHEMISTRY HELP PLEASE!!!
The solubility of AgCl(s) in water at 25 C is 1.33x10^-5 M and its delta H of solution is 65.7 kJ/mol . What is its solubility at 60.1 C ?
Saturday, March 23, 2013 at 7:13pm

chemistry
how many grams of Ag2CO3 will precipitate when excess Na2CO3 solution is added to 64.0 mL of 0.554 M AgNO3 solution?
Saturday, March 23, 2013 at 7:12pm

Chemistry
Assuming complete dissociation, what is the pH of a 2.55 mg/L Ba(OH)2 solution?
Saturday, March 23, 2013 at 6:56pm

Chemistry
A solution contains 25 mmol of H3PO4 and 10. mmol of NaH2PO4. What volume of 2.0 M NaOH must be added to reach the second equivalence point of the titration of the H3PO4 with NaOH?
Saturday, March 23, 2013 at 5:32pm

chem
(b) (4 pts.) Suppose it is a hot summer day (40.0 degrees C = 104.0 degrees F), and you have left a can of hairspray outside so the gas within it is now at the same temperature of its surroundings. As part of your chemistry lab class, you have to build a safe and effective ...
Saturday, March 23, 2013 at 5:18pm

Chemistry
Consider the titration of 100.0 mL of 0.100 M H2NNH2 (Kb = 3.0 10-6) by 0.200 M HNO3. Calculate the pH of the resulting solution after the following volumes of HNO3 have been added. a)0.0 mL b)20.0 mL c)25.0 mL d)40.0 mL e)50.0 mL f)100.0 mL
Saturday, March 23, 2013 at 4:37pm

Chemistry
Suppose that 2.3 L of gas at 35°C and 1.0 atm is expanded to 4.5 L at 42°C. What will the final pressure of the gas be? (Ti in Kelvins=308.15; Tf(K)=315.15) Can someone please show me how to plug the values into the Combined Gas Law formula to calculate for Pf? Please ...
Saturday, March 23, 2013 at 4:09pm

chemistry
Consider an electron in the ground state of hydrogen. (a)What is the least amount of energy needed to excite the ground state electron in Joules? (b) Is an electron in the ground state of hydrogen capable of absorbing a photon with energy of 1.38e-18 Joules.
Saturday, March 23, 2013 at 4:07pm

chemistry
Tantalum metal is produced by reaction of potassium heptafluorotantalate (K2TaF7) with elemental sodium (Na) in a reactor heated to 850oC. The by-products are potassium fluoride (KF) and sodium fluoride (NaF). The reactor is charged with 208.0 kg of K2TaF7 and 28.0 kg of Na. ...
Saturday, March 23, 2013 at 4:07pm

chemistry
Atoms of ionized lithium gas (Li2+) are struck by neutrons moving at a velocity of 1.46e5 m/s. Calculate the shortest wavelength in the emission spectrum of Li2+ under these circumstances. You can assume that all electrons start in the ground state. Enter the wavelength in m:
Saturday, March 23, 2013 at 3:58pm

chemistry
A particle wavelength (λp) of a proton is 10-12m. What is the velocity of this proton [m/s]? To achieved the velocity that you just computed, what must have been the potential difference (V) through which the proton was accelerated? An electron of wavelength 1.74*10-10m ...
Saturday, March 23, 2013 at 3:57pm

chemistry
Calculate the enthalpy of atomization per unit volume for Rb. Express your answer in kJ/m3. Determine the volume (in mL) occupied at room temperature by 3.5e22 mercury (Hg) atoms in the liquid state.
Saturday, March 23, 2013 at 3:57pm

chemistry
Calculate the atomic weight of an element (X) given the following information: 26X: 26.000 amu at 0.1102 fractional abundance 28X: 28.000 amu at 0.6487 fractional abundance 29X: 29.000 amu at 0.2411 fractional abundance What element might the above problem describe? Please ...
Saturday, March 23, 2013 at 3:56pm

chemistry
(a) Consider the gaseous molecule BN-. At home, construct the molecular orbital diagram that is consistent with the known order of filling of molecular orbitals in the second period and with BN- being stable and paramagnetic. What is the bond order of BN-? (c) What ion of BN ...
Saturday, March 23, 2013 at 3:55pm

chemistry
Magnesium can be produced by reaction of magnesium oxide (MgO) with silicon (Si). The by-product of the reaction is magnesium orthosilicate (Mg2SiO4). A reactor is charged with 183.0 kg of MgO and 116.0 kg Si. Assume the reaction goes to completion. Express your answers in kg...
Saturday, March 23, 2013 at 3:32pm

chemistry
A gas in a discharge tube consists entirely of ions of the same element, of the same charge. Each ion has only one remaining electron. The voltage between the electrodes of the gas discharge tube is increased from zero. Electrons are accelerated across the potential, and then ...
Saturday, March 23, 2013 at 3:07pm

Chemistry
Calculate amount (in grams) of unknown acid used for titration. You want 30 mL of titrant to get the equivalence point. Assume that the base is 0.05 M and the unknown acid molar mass is around 400 g/mol.
Saturday, March 23, 2013 at 1:37pm

Chemistry
What molar ratio of acetic acid to sodium acetate is required to create a buffer solution having a pH of 4.83 at 25 Celsius? Ka for HC2H3O2 is 1.8 x10^-5 a)0.82 b)0.55 c)3.5 d)1.2 e)2.0 The answer I got was 8.2 ..(help!)
Saturday, March 23, 2013 at 12:48pm

Chemistry
A chemist dissolves 0.095 g of CuSO4 · 5H2O in water and dilutes the solution to the mark in a 500-mL volumetric flask. A 39.7-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 ...
Saturday, March 23, 2013 at 10:09am

Chemistry
3. Which oxidation-reduction reactions are best balanced by the half-reaction method? A.) covalent reactions *B.)acid-base reactions C.) ionic reactions D.) intermolecular reactions Thank you.
Saturday, March 23, 2013 at 9:50am

Physical Chemistry
An electron of wavelength 1.74*10-10m strikes an atom of ionized helium (He+). What is the wavelength (m) of the light corresponding to the line in the emission spectrum with the smallest energy transition?
Saturday, March 23, 2013 at 9:04am

chemistry
Atomic sodium is studied by photoelectron spectroscopy. What is the maximum wavelength of the incident radiation that will ionize the most weakly held electrons in sodium and scatter them so that their de Broglie wavelength measures 3.091e-10 m?
Saturday, March 23, 2013 at 6:17am

chemistry
An electron of wavelength 1.74*10-10m strikes an atom of ionized helium (He+). What is the wavelength (m) of the light corresponding to the line in the emission spectrum with the smallest energy transition?
Saturday, March 23, 2013 at 6:01am

Chemistry
Please tell me which Gas Law equation to use to figure out this problem... A helium balloon at 25°C, 1 atm, has a volume of 2.88 L. Additional helium is pumped into the balloon. It now contains 1.20 g of He and its new volume is 7.20 L. How many moles of helium gas did the...
Saturday, March 23, 2013 at 2:23am

chemistry
Consider a solution made by mixing 500.0 mL of 0.04182 M Na2HAsO4 with 500.0 mL of 0.03645 M NaOH. Complete the mass balance expressions below for Na and arsenate species in the final solution. There are 4 arsenate species, but I only got three of them. I am unsure of what the...
Saturday, March 23, 2013 at 12:34am

Chemistry
What is the hydronium ion concentration of a buffer solution that is 0.10M NaHPO4 and 0.50M NaH2PO4? For H3PO4,Ka1=6.9x10^-3, Ka2=6.2x10^-8, Ka3=4.8x10^-13
Friday, March 22, 2013 at 11:58pm

Chemistry
What is the hydrogen-ion concentration of a solution that is 0.016M in acetic acid and 0.016M in sodium acetate at 25 Celsius? The Ka for acetic acid is 1.8x10^-5
Friday, March 22, 2013 at 11:54pm

Chemistry
The amount of energy released by burning a fuel source, measured in energy per mass, is called the fuel value. If all the energy obtained from burning 1.25 pounds of butane (fuel value is 10.85 kcal/g) is used to heat 120.0 kg of water at an initial temperature of 21.2 °C...
Friday, March 22, 2013 at 10:56pm

Chemistry
Calculate the pH of a solution that is 2.00M HF, 1.00M NaOH, and 0.393M NaG (Ka=7.2 x10^-4). The answer I got was 4.76 ..
Friday, March 22, 2013 at 9:45pm

Chemistry
what is the pH of a solution prepared by adding 0.259g of ammonium chloride to 115mL of water? Kb of NH3 is 1.8x10^-5
Friday, March 22, 2013 at 9:26pm

Chemistry
What coefficient of H+ balances the atoms in the following half-reaction? H^+ + MnO2 Mn^2+ + H2O A.1 B.2 C.3 D.4 I think this is B...?
Friday, March 22, 2013 at 9:00pm

Chemistry
What is the reduction half-reaction for the following unbalanced redox equation? Cr2O7^2– + NH4^+ Cr2O3 + N2 A.Cr2O3--> Cr2O7^2– B.Cr2O7^2– --> Cr2O3 C.NH4^+ --> N2 D.N2 --> NH4^+ I think this is D...?
Friday, March 22, 2013 at 8:58pm

Chemistry
Calculate the molarity of the nitrate ion in a 0.111 M solution of calcium nitrate? so would I have to find the number of moles of (NO3)2 and then divide it by the 0.111 M to get the molarity of the nitrate ion I am so confused please explain the set up I don't want the ...
Friday, March 22, 2013 at 8:01pm

Chemistry
2M +6HCl–>2MCl+3H2 Delta H= -638.0 Kj HClg—>HCl aq= Delta H -74.8 Kj H2+Cl2–>2HCl Delta H -1845.0 Kj MCl3s–> MCl3 aq Delta H -249.0 Kj Use the information above to determine the enthalpy of the following reaction. 2M +3Cl2–>2MCl3 Delta H...
Friday, March 22, 2013 at 7:52pm

Chemistry
Atoms of ionized lithium gas (Li2+) are struck by neutrons moving at a velocity of 1.46e5 m/s. Calculate the shortest wavelength in the emission spectrum of Li2+ under these circumstances. You can assume that all electrons start in the ground state.
Friday, March 22, 2013 at 7:48pm

Chemistry
A gas in a discharge tube consists entirely of ions of the same element, of the same charge. Each ion has only one remaining electron. The voltage between the electrodes of the gas discharge tube is increased from zero. Electrons are accelerated across the potential, and then ...
Friday, March 22, 2013 at 7:38pm

Chemistry: check answers
Please check. Thank you. 2. What is the reduction half-reaction for the following unbalanced redox equation? Cr2O72– + NH4+ Cr2O3 + N2 A.) Cr2O3 -> Cr2O72– B.) Cr2O72– -> Cr2O3 C.) NH4+ -> N2 D.) N2 -> NH4+ 3. Which oxidation-reduction reactions are ...
Friday, March 22, 2013 at 6:12pm

Chemistry
At constant volume the heat of combustion of a particular compound is -3378.0 kj/mol.When 1.563 g of this compound ( molar mass of 126.88 g/mol )was burned temp rose 6.991 C. What's the heat capacity of the calorimeter(calorimeter is constant)?
Friday, March 22, 2013 at 6:08pm

chemistry
Suppose you have 19.2 g of Cu. What number of moles of Cu is present? Report your answer to 3 signifiant figures.
Friday, March 22, 2013 at 4:17pm

Chemistry
what is the hydronium-ion concentration in a 0.35m solution of NaCO3? For carbonic acid, Ka1=4.2x10^-7 and Ka2=4.8x10^-11. (Kw=1.0x10^-14)
Friday, March 22, 2013 at 2:45pm

Chemistry
What is Kc for the following equilibrium? For phosphoric acid, Ka1=6.9x10^-3, Ka2=6.2x10^-8 and Ka3=4.8x10^-13 HPO4^-2 + OH^- <==> PO4^-3 + H2O
Friday, March 22, 2013 at 2:41pm

quantitative chemistry
Consider a solution made by mixing 500.0 mL of 0.04182 M Na2HAsO4 with 500.0 mL of 0.03645 M NaOH. Complete the mass balance expressions below for Na and arsenate species in the final solution. There are 4 arsenate species, but I only got three of them. I am unsure of what the...
Friday, March 22, 2013 at 2:23pm

quantitative chemistry
Determine [Zn2 ], [CN–], and [HCN] in a saturated solution of Zn(CN)2 with a fixed pH of 1.78. The Ksp for Zn(CN)2 is 3.0 × 10–16. The Ka for HCN is 6.2 × 10–10. I know the following is what needs to be done, but im unsure of how to go about it. 1. ...
Friday, March 22, 2013 at 2:06pm

Chemistry
Please help me solve this question: A layer of peat beneath the glacial sediments of the last ice age had a carbon-14 content of 25% of that found in living organisms. How long ago was this ice age?
Friday, March 22, 2013 at 2:03pm

chemistry
how many phases do suspensions have?
Friday, March 22, 2013 at 1:57pm

Chemistry -Please Help
2. What is the reduction half-reaction for the following unbalanced redox equation? Cr2O7^2– + NH4^+ Cr2O3 + N2 A.) Cr2O3 -> Cr2O7^2– B.) Cr2O7^2– -> Cr2O3 C.) NH4^+ -> N2 D.) N2 -> NH4^+ I think it is B...? 3. Which oxidation-reduction reactions are...
Friday, March 22, 2013 at 1:39pm

Chemistry
What is the pH of a .0035 M Ba(OH)2 solution. I did -log(.0070) to find pOH So 14-2.15=11.85 pH? Just want to double check.
Friday, March 22, 2013 at 1:21pm

Chemistry;HELP
How would you do this problem? /: 1. Calculate the density of a material that has a mass of 52.497grams and a volume of 18.5cm^3?
Friday, March 22, 2013 at 1:14pm

chemistry
draw all possible z isomers for an alkene with the formula C4H7Br. im having some difficulty, please help
Friday, March 22, 2013 at 12:52pm

Chemistry (2 questions)
1. What kinds of bonds will most likely form from groups 1,2,3,6,7, and 8 on the periodic table? 2. What kinds of bonds will most likely form from group 4 on the periodic table?
Friday, March 22, 2013 at 12:50pm

Chemistry
The value of Kc for the reaction below is 1.6 C(s)+CO2(g)=2CO(g) What is the equilibrium concentration of CO when [CO2]=.50M? The usual ICE table doesn't work for me. C(s)+CO2(g)=2CO(g) I - 0 C -x +2x E .50 +2x 1.6=[2x]^(2)/(.50) That's how I did it but the answer is ....
Friday, March 22, 2013 at 12:42pm

Chemistry
A tank contains exactly 10^(6)liters of pure water. 1.0*10^(-6) moles of HCl (g) is bubbled into this tank. What is the resulting pH? The answer is 7, but I was only able to deduce that based on the fact that water has a neutral pH, but there's a mathematical way to do it ...
Friday, March 22, 2013 at 12:35pm

Chemistry
2. What is the reduction half-reaction for the following unbalanced redox equation? Cr2O72– + NH4+ Cr2O3 + N2 A.) Cr2O3 -> Cr2O7^2– *B.) Cr2O72– -> Cr2O3 C.) NH4+ -> N2 D.) N2 -> NH4+ 3. Which oxidation-reduction reactions are best balanced by the ...
Friday, March 22, 2013 at 12:08pm

chemistry
2. What is the reduction half-reaction for the following unbalanced redox equation? Cr2O72– + NH4+ Cr2O3 + N2 A.) Cr2O3 -> Cr2O7^2– *B.) Cr2O72– -> Cr2O3 C.) NH4+ -> N2 D.) N2 -> NH4+ 3. Which oxidation-reduction reactions are best balanced by the ...
Friday, March 22, 2013 at 11:18am

Chemistry
What is the percent ionization of a solution prepared by dissolving 0.0286mol of chloroacetic acid, in 1.60L of water?for choloroacetic acid, Ka=1.4x10^-3
Friday, March 22, 2013 at 10:58am

Chemistry
How many liters of ammonia gas can be formed from 11.3 L of hydrogen gas at 93.0 C and a pressure of 42.4 kPa?
Friday, March 22, 2013 at 10:26am

Chemistry
what is Kc at 25 celsius for the following equilibrium? CH3BH3^+ +H2O <==> CH3NH2 + H3O^+ Kb=4.4x10^-4 I got 4.0x10^4 / 1.0x10^-14 = 4.0x10^-10 (correct)?
Friday, March 22, 2013 at 10:03am

chemistry
why is it necessary to try and keep the temperature constant during an experiment of determining pKa by pH measurements?
Friday, March 22, 2013 at 7:06am

chemistry
how do i calculate the NaOH molarity from a titration of KHP and NaOH after preparing KHP to standardise NaOH. KHP mass was 2.0378g dissoveld in distilled water to fill up a 100ml volumetric flask and only 10ml of this solution was used to in titration
Friday, March 22, 2013 at 7:00am

Chemistry
How many moles of NaCl are in 2.00mL of 1.00M NaCl?
Thursday, March 21, 2013 at 11:00pm

Chemistry
How many grams of bromine are required to react completely with 37.4 grams aluminum chloride?
Thursday, March 21, 2013 at 10:58pm

Chemistry
How many grams of bromine are required to react completely with 3704 grams aluminum chloride?
Thursday, March 21, 2013 at 10:57pm

Chemistry
the ka of hypochlorous acid hclo is 3.5 x 10^-8. What is Kb for the hypochlorite ion?
Thursday, March 21, 2013 at 10:38pm

Chemistry
what is the Ka for ethylammonium cation,C2H5NH3^+, at 25 celsius?(Kb for C2H5NH2=4.7x10^-4 at 25 Celsius)
Thursday, March 21, 2013 at 10:34pm

organic chemistry
which of the following represents the best strategy for synthesizing 2-butanol, CH3CH2CH(OH)CH3 a) CH3CH=CHCH3 + [H30]+ b) CH3CH2C (triple bond) CH + [H3O]+ c) CH3CH=CH2+ [CH3OH2]+ d) CH3C (triple bond)CCH3 + [H3O]+
Thursday, March 21, 2013 at 10:30pm

Chemistry
The solubility of iron(III)hydroxide is 4.39E-10M. What is the Ksp for this compound? I don't know how I would go about this problem.
Thursday, March 21, 2013 at 9:33pm

Chemistry
What is the pH of a solution that is .060M in potassium propionic and .085M in propionic acid? Ka=1.3E-5 for the acid. The answer is +4.73 but I don't know how to go about the problem. I thought that the potassium propionic was reacting with the acid to form their ...
Thursday, March 21, 2013 at 9:20pm

Chemistry
What is PVA glue?
Thursday, March 21, 2013 at 8:54pm

Chemistry
What is PAV glue?
Thursday, March 21, 2013 at 8:51pm

Chemistry
How many moles of ethyl alcohol C2H6O are in a 25.0 sample? How do I calculate?
Thursday, March 21, 2013 at 8:15pm

Chemistry
Can PbCO3 + AgNO3 yield any product? Or do these two not react? If they don't react, can you please explain why? If they do, what is/are the product(s) and the balanced equation?
Thursday, March 21, 2013 at 8:07pm

Chemistry
I am working a question...... I am not sure how to go about solving this or working it out. The class is online. Can some explain how to go about doing this. Thank you greatly :) How much heat does your body lose when 2.60g of sweat evaporates from your skin at 25C? (Assume ...
Thursday, March 21, 2013 at 5:58pm

AP chemistry
1). In a titration 20 mL of 0.100 M of HCl is added to 50.0 mL of 0.150 M of ammonia. A). What is the pH of NH3? B). What is the pH of the resulting solution? HELP :(
Thursday, March 21, 2013 at 5:52pm

CHEMISTRY
Suppose a 24.7 mL sample of helium gas at 25.°C and 1.14 atm is heated to 50°C and compressed to a volume of 14.8 mL. What will be the pressure of the sample? My teacher got 2.06 atm. pls explain to me how he got this. THANK YOU
Thursday, March 21, 2013 at 5:44pm

chemistry
Determine the molar solubility (S) of Zn(CN)2 in a solution with a pH = 4.91. Ksp (Zn(CN)2) = 3.0 × 10-16; Ka (HCN) = 6.2 × 10-10.
Thursday, March 21, 2013 at 4:59pm

Chemistry
Which of the following salts is NOT more soluble in acidic solution than in pure water? A. ZnS B. AgCN C. Ba3(PO4)2 D. ZnCO3 E. BiI3 The answer is E, but I don't know why or how I would go about answering a question like this. What would I have to consider to determine this?
Thursday, March 21, 2013 at 4:12pm

Chemistry
How many moles of H20 are in 430g of H20?
Thursday, March 21, 2013 at 3:45pm

chemistry
Ignoring activities, determine the molar solubility of copper (I) azide (CuN3) in a solution with a pH of 10.83. Ksp (CuN3) = 4.9 × 10–9; Ka (HN3) = 2.2 × 10–5.
Thursday, March 21, 2013 at 3:43pm

Chemistry
What is the reducing agent in the following reaction? 2NA + 2H2O 2NaOH + H2 A.Na B.H2O C.NaOH D.H2 I think it is B...?
Thursday, March 21, 2013 at 3:08pm

Chemistry
Identify the atom that increases in oxidation number in the following redox reaction. 2MnO2 + 2K2CO3 + O2 2KMnO4 + 2CO2 *A.) Mn B.) O C.) K D.) C Please show work Thank you.
Thursday, March 21, 2013 at 3:03pm

Chemistry
A sealed 1.0L flask is charged with .500mol I2 and .500mol Br2 and an equilibrium reaction esues: I2(g)+Br2(g)=2IBr(g) When the container contents achieve equilibrium, the flask contains .84 mol of IBr. What is the value of the eqilibrium constant? (K)
Thursday, March 21, 2013 at 2:21pm

Chemistry
Why does the color of Methyl Orange change at all in he presence of buffer components?
Thursday, March 21, 2013 at 1:56pm

chemistry
Air trapped in a cylinder fitted with a piston occupies 145.7 mL at 1.08 atm pressure. What is the new volume of air when the pressure is increased to 1.34 atm by applying force to the piston?
Thursday, March 21, 2013 at 12:54pm

chemistry
What is the chemical equation of methylamine with CuSO4?
Thursday, March 21, 2013 at 8:24am

chemistry
Copper container can be used to store (A) Al2(SO4)3 solution (B) ZnSO4 solution (C) FeSO4 solution (D) All of these
Thursday, March 21, 2013 at 7:43am

chemistry
Condition Pressure Volume Temperature Comment initial 1.0 atm 22.4 L 273 K 1 mole of N2 gas fills the tank. final 3.0 atm 22.4 L 273 K 2 moles of O2 gas have been added to the 1 mole of N2 gas in the tank. Key Questions 7. What was the initial pressure caused by the nitrogen ...
Thursday, March 21, 2013 at 6:42am

chemistry
What is the solubility of AgCrO4 (Ksp= 9.0 x 10^-12) in distilled water?
Thursday, March 21, 2013 at 3:04am

Chemistry
Calculate the pOH of an aqueous solution of 146.6 ml of 0.000625 M HBr(aq) after dilution to 850 ml.
Thursday, March 21, 2013 at 1:37am

Chemistry
Suppose that 10.9 mL of HNO3 is neutralized by 83.9 mL of a 0.0021 < solution of KOH in a titration. Calculate the concentration of the HNO3 solution. Answer in units of M
Thursday, March 21, 2013 at 1:26am

Chemistry
Why is a dilute solution of boric acid H3BO3 used as an eyewash? How does it work in cleansing the eye from chemicals?
Wednesday, March 20, 2013 at 11:55pm

chemistry
What is the limiting reagent in this problem? A total of 40.0 mL of 0.55 M copper (II) sulfate solution is added to a beaker containing 2.02g of zinc.
Wednesday, March 20, 2013 at 10:53pm

Chemistry
How many milliliters of 6.50 M HCl(aq) are required to react with 5.95 g of an ore containing 35.0% Zn(s) by mass?
Wednesday, March 20, 2013 at 10:43pm

Chemistry
A 5.0-g Sample of KBr at 25.0 degrees celsius dissolves 25.0 mL of water also at 25.0 degrees celsius. The final equilibrium temperature of the resulting soltution is 18.1 degrees celsius. What is the enthalpy of of solution in kilojoules per mole of KBr?
Wednesday, March 20, 2013 at 10:23pm

chemistry
How many mL of 0.40M NaOH are need to neutralize 30.0 mL of 0.50 M H2SO4 according to the following reaction. 2NaOH(aq) + H2SO4 (aq)----Na2SO4 (aq) + 2H2O(l)
Wednesday, March 20, 2013 at 9:55pm

Chemistry
At 122C the pressure of a sample of nitrogen gas is 0.830 atm. what will the temperature in Celsius be at 3.00 atm, assuming constant volume ?
Wednesday, March 20, 2013 at 8:54pm

Chemistry
If you add 100 g of salt to 5 Kg of cooking water, how will it effect the boiling point? (molar mass of NaCl 58.5 g, Kbwater=0.51 degrees/m)
Wednesday, March 20, 2013 at 8:47pm

Chemistry
1) What volume of 1.25 mol/L hydrobromic acid, HBr(aq) will neutralize 75.0 ml of 0.895 mol/L magnesium hydroxide Mg(OH)2(aq)? 2) a 25.00 mL sample of a nitric acid solution , HNO3(aq) is neutralized by 18.55mL of a 0.1750 mol/L sodium hydroxide, NaOH(aq) what is the ...
Wednesday, March 20, 2013 at 8:38pm

Chemistry
Given Zn(NO3)2 + (NH4)2S = ZnS + 2NH4NO3 (molar mass of Zn(NO3)2 189 g, molar mass of (NH4)2S 68 g), what is the molarity of a 250 ml solution if you have 123 g of zinc nitrate?
Wednesday, March 20, 2013 at 8:31pm

chemistry
2NOBr(g) <==> 2NO(g) + Br2(g) and the value of Kc = 1.98, at a temperature of 282 K what is the value of Kp ? (Hint: Use the value of R in the appropriate units.)
Wednesday, March 20, 2013 at 8:31pm

chemistry
How many Liters of a 5.00 M Zn(NO3)2 would be needed to react with 200 g of (NH4)2S?
Wednesday, March 20, 2013 at 8:20pm

Chemistry
7. A solution is prepared by dissolving 8.5 g NaHCO3 and 12.7 g Na2CO3 in 500.0 mL of water. Calculate the pH.
Wednesday, March 20, 2013 at 7:12pm

Chemistry
7. A solution is prepared by dissolving 8.5 g NaHCO3 and 12.7 g Na2CO3 in 500.0 mL of water. Calculate the pH.
Wednesday, March 20, 2013 at 7:11pm

Chemistry
Find the pH: 1) A 0.001M solution of HCl 2) A 7.98 x 10^-2 M solution of HNO3 3) 1098L of a solution containing 8.543moles of HBr 4) 120mL of a solution containing 0.005 grams of hydrochloric acid. Please help me with these four. Out of 20 questions i only didn't ...
Wednesday, March 20, 2013 at 7:01pm

Chemistry
Which of the following pairs would make a good buffer solution in an aqueous solution? A) H2SO4 and NaHSO4 B) Ca(NO3)2 and HNO3 C) HCl and NaCl D) HF and NaOH E) none of them I know the answer is D but I don't understand why. I would think it would be C since a goo buffer ...
Wednesday, March 20, 2013 at 6:47pm

chemistry
CuSO4+4NH3-Cu(NH3)4SO4 a. if you use 10.0g 0f CuSO4 and excess NH3, What is the theoretical yield of Cu(NH3)4SO4? b. if you produce 12.6g of Cu(NH3)4SO4, What is the percent yield of the compund?
Wednesday, March 20, 2013 at 6:31pm

Chemistry
1. The reaction CO+2H2-CH3OH was carried and it is found that only 332g of CH3Oh is actually produced when 407g CH3Oh was the expected yield. What is the Percent yield? 2. If 112g of CaO is reactied with an excess of NH4Cl and 64.0g of NH3 are produced, what is the percent ...
Wednesday, March 20, 2013 at 6:22pm

chemistry
if a total of 18.6 mol of NaHCO3, and 6.2 mol of C6H8O7 react, how many moles of CO2 and Na3C6H5O7 will be produced?
Wednesday, March 20, 2013 at 4:23pm

Chemistry
On Easter Sunday, April 23, 1983, nitric acid (HNO3) spilled from a tank car near downtown Denver, Colorado. The spill was neutralized with sodium carbonate (Na2CO3). 2HNO3(aq) + Na2CO3(s) -> 2NaNO3(aq) + H2O(l) + CO2(g) deltaH=-69.0kJ a. How much heat is released by the ...
Wednesday, March 20, 2013 at 4:16pm

chemistry
The most common source of copper (\rm Cu) is the mineral chalcopyrite (\rm CuFeS_2). How many kilograms of chalcopyrite must be mined to obtain 210.g of pure \rm Cu?
Wednesday, March 20, 2013 at 4:05pm

CHEMISTRY
How do you get the concentration with buret readings? What would the concentration of HC2H3O2 (M) be? For example, Molarity of the NaOH solution: 0.2619 M Final buret reading: 31.10 ml Initial buret reading: 0 Volume of NaOH solution: 31.0 ml concentration of HC2H3O2 (M...
Wednesday, March 20, 2013 at 3:58pm

Chemistry
Calculate the pH of a buffer solution containing 1.0 M ammonia (NH3 ; Kb = 1.8 x 10-5) and 1.0 M ammonium chloride (NH4Cl).
Wednesday, March 20, 2013 at 3:35pm

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