Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

Chemistry
What is the percent by mass of glucose in a solution containing .15 mol of glucose dissolved in 410 g acetic acid? The molar mass of glucose is 180g/mol.
Friday, March 1, 2013 at 11:22am

Chemistry
0.15g of hydrogen chloride HCl is dissolved in water to make 8.0L of solution. What is the pH of the resulting hydrochloric acid solution?
Friday, March 1, 2013 at 10:46am

chemistry
A buffer is made by combining 3.50 L of 0.200M butylamine, C4H9NH2 with 7.50L of 0.100M butylammonium chloride, C4H9NH3Cl. Assuming that volumes are additive, calculate the following. A) the pH of the buffer. B) the pH of the buffer after the addition of 35.0mL of 0.080M NaOH ...
Friday, March 1, 2013 at 10:42am

chemistry
6.25 L of a propanoic acid-propanoate buffer must be prepared. The pH of the buffer needs to be 5.05. The solution will be 0.120M in propanoic acid. If the propanoate ion comes from the strontium propionate Sr(C3H5O2)2 then how many grams of strontium propanoate are needed?
Friday, March 1, 2013 at 10:37am

IB Chemistry
Why don't we use the bomb calorimeter to calculate the heat energy in the combustion of alcohol but we use the copper cup calorimeter?
Friday, March 1, 2013 at 8:28am

chemistry
A 115 g piece of metal, initially at 60.0 °C, is submerged into 100.0 g of water at 25.0 °C. At thermal equilibrium, this mixture had a final temperature of 27.0 °C. The specific heat capacity of water is 4.18 (J/g°C). Use this information to determine the ...
Friday, March 1, 2013 at 8:27am

chemistry
Which compound would you expect to have the highest melting point? BeO MgO CaO SrO
Friday, March 1, 2013 at 4:13am

Chemistry
There are several technological applications for the transuranium elements (Z > 92). An important one is in smoke detectors, which can use the decay of a tiny amount of americium-241 to neptunium-237.What subatomic particle is emitted from that decay process? Write a ...
Friday, March 1, 2013 at 3:39am

Chemistry
Radium-223 has a half-life of 11.4 days.Approximately how long would it take for the activity of a sample of Radium-223 to decrease to 1.00% of its initial value?
Friday, March 1, 2013 at 2:44am

chemistry
At 0*C a 1.0-L flask contains 5.0 x 10^-2 mol N2, 1.5 x 10^2 mg O2, and 5.0 x 10^21 molecules of NH3. What is the partial pressure of each gas, and what is the total pressure in the flask?
Friday, March 1, 2013 at 1:43am

Chemistry
What is the complete and net ionic equations for: Cu+Zn+2HCl--> ZnCl2+Cu+h2
Friday, March 1, 2013 at 12:40am

IB Chemistry
Which statements are correct for an endothermic reaction? I. The system absorbs heat. II. The enthalpy change is positive. III. The bond enthalpy total for the reactants is greater than for the products. A. I and II only B. I and III only C. II and III only D. I, II and III ...
Thursday, February 28, 2013 at 11:57pm

chemistry
supposed we mixed 50.0mL of alcohol w/ enough water to make 400mL solution find the % age by volume of 50L??? what is the answer plz answer my qeustion!!!
Thursday, February 28, 2013 at 10:22pm

chemistry
Calculate the temperature at which it is thermodynamically possible for C (s) to reduce iron(III) oxide by the reaction: 2Fe2O3 (s) + 3 C (s) ---> 4Fe (s) + 3CO2 I don't need a specific answer, but I'm not sure how to approach the problem. I'm assuming it has to...
Thursday, February 28, 2013 at 10:15pm

ap chemistry
Which of I) HCl II) HF III) LiOH IV) HClO2 V) HNO3 are strong acids or strong bases in water?
Thursday, February 28, 2013 at 10:00pm

ap chemistry
Acid rain has a pH value of 3.0, whereas normal rain has a pH value of 5.6. Calculate the ratio of the hydronium ion in acid rain to that in normal rain.
Thursday, February 28, 2013 at 9:47pm

chemistry
The gaseous product of a reaction is collected in a 12.0 L container at 280C. The pressure in the container is 3.5 atm and the gas has a mass of 96.0 g. What is the molecular mass of the gas?
Thursday, February 28, 2013 at 9:39pm

chemistry
mass of the metal 7.26g volume of water in the calorimeter 10mL initial temp of water in calorimeter 21.5 degrees C initial temp of metal 95.5 d C final temp in mixture in calorimeter 23.8 D C question: calculate the energy lost by the metal taking into consideration that it ...
Thursday, February 28, 2013 at 8:52pm

chemistry
A certain reaction has an activation energy of 27.34 kJ/mol. At what Kelvin temperature will the reaction proceed 3.50 times faster than it did at 335 K?
Thursday, February 28, 2013 at 8:41pm

chemistry
the rate of the following reaction is 0.72 M/s. what is the relative rate of change of each species in the reaction? A+4B -> 2C
Thursday, February 28, 2013 at 8:05pm

chemistry
3 MgCl2(aq) + 2 Na3PO4(aq) ==> Mg3(PO4)2(s) + 6 NaCl(aq) How many milliliters of 0.0800 M Na3PO4(aq) will react with 0.060 mol of MgCl2(aq)?
Thursday, February 28, 2013 at 7:38pm

chemistry
To raise the temperature of 200.8 g of water from 50.00 °C to 60.00 °C requires how much heat?
Thursday, February 28, 2013 at 7:15pm

Chemistry
for an assignment I'm writing, I'm trying to find the % efficiency of ethanol. We were given a chart that says ethanol's energy input (MJ/L) is 16.16 and its energy output is 23.58 % efficiency = energy output/energy input x100, so 23.57/16.16 x 100 I get 146%. So ...
Thursday, February 28, 2013 at 6:49pm

Chemistry
Calculate the wavelength of light if 1.50 mol of photons has an energy of 125 kJ. 6.02x10^23 things=1.00 mol(things) c=3.00x10^8 m/sec h=6.626x10^-34 J sec
Thursday, February 28, 2013 at 6:44pm

Chemistry
Would you balance this one SO2 + O2. SO3 Like 2SO2 + O2. 2SO3
Thursday, February 28, 2013 at 6:26pm

Chemistry
How do you balance Fe2O3+C. 2Fe+CO2
Thursday, February 28, 2013 at 5:56pm

Analytical Chemistry
A 22.617 g sample of aqueous waste leaving a fertilizer manufacturer contains ammonia. The sample is diluted with 70.407 g of water. A 10.883 g aliquot of this solution is then titrated with 0.1072 M HCl. It required 29.32 mL of the HCl solution to reach the methyl red ...
Thursday, February 28, 2013 at 5:04pm

chemistry
2.06 X 10^25 formula units of aluminum sulfate would have what mass?
Thursday, February 28, 2013 at 5:02pm

chemistry
1040 grams of chlorine gas at STP would have what volume?
Thursday, February 28, 2013 at 5:01pm

chemistry
If you are given 718 grams of lead (iv) oxalate, how many atoms of oxygen do you have?
Thursday, February 28, 2013 at 4:59pm

Chemistry
Calculate the mass of HONH2 required to dissolve in enough water to make 255.5 mL of solution having a pH of 10.02 (Kb = 1.110−8).
Thursday, February 28, 2013 at 4:48pm

Chemistry
What is the mass of the carbon atoms in one mole of c3h8
Thursday, February 28, 2013 at 1:26pm

Chemistry
The standardized NaOH solution was determined to be 120M whereas the mass of the sample of impure tartaric acid was 1.35g. If the initial reading of the buret volume changed from 48 ml to a final reading of 17 ml at the endpoint of the titration of the impure sample calculate ...
Thursday, February 28, 2013 at 12:03pm

Chemistry
calculate the amount of energy required to vaporize 43.0g of water at its boiling point
Thursday, February 28, 2013 at 11:33am

chemistry
What is the volume occupied by 20.2g NH3(g) at -25 degrees celsius and 752 mmHg? This is Ideal Gas Law.
Thursday, February 28, 2013 at 10:20am

chemistry
Which of the following statements is /are true? Answer a. None of he above. b. Impurities in a solvent raise the freezing point of that solvent c. All of the above d. Non-volatile impurities lower the boiling point of a solvent e. Ions lower the vapor pressure of a solvent ...
Thursday, February 28, 2013 at 10:12am

Chemistry
Pantothenic acid id one of the B vitamins. A sample of pantothenic acid was found to produce 3.84 mL of nitrogen gas, N2 at 23 degrees celsius and 785 mmHg. What is the volume of the nitrogen gas (in liters) produced as 29 degrees celsius and 0.993 atm?
Thursday, February 28, 2013 at 8:47am

Chemistry
30cm of 0.3molar solution (0.3mol) were diluted to 0.1molar solution(0.1mol) by addition of water calculate A. The new molar solution B. Volume of water added
Thursday, February 28, 2013 at 2:52am

Chemistry
An electrolytic tin-coating process gives the coating 30 millionths of an inch thick. How many square meters can be coated with one kilogram, density 7.30 g/cm^3?
Thursday, February 28, 2013 at 2:48am

general chemistry
When divers exhale beneath the surface of the water, bubbles rise to the surface. Explain this behavior.
Wednesday, February 27, 2013 at 11:12pm

ap chemistry
Given the following information, which of the following shows the acids in order from strongest to weakest? The order of atomic radii is I > Br > Cl, the order of bond strengths is HOI > HOBr > HOCl, and the order of electronegativities is Cl > Br > I.
Wednesday, February 27, 2013 at 11:07pm

general chemistry College
Which of the following mixture would be most likely to produce carbon dioxide? Explain Why? a. magnesium and nitric acid: Mg+ HNO3 b. sodium carbonate and sufuricacid: Na2CO3+H2SO4 c. H2O+ Cu
Wednesday, February 27, 2013 at 11:05pm

chemistry
How many liters of 2.09 HCl solution would be needed to prepare 1.14 L of 0.69 M HCl solution?
Wednesday, February 27, 2013 at 10:53pm

ap chemistry
Arrange the bases I) deuterated ammonia (ND3) Kb = 1.1 × 10−5; II) hydrazine (NH2NH2) Kb = 1.7 × 10−6; III) hydroxylamine (NH2OH) Kb = 1.1 × 10−8; IV) ammonia (NH3) Kb = 1.8 × 10−5; in decreasing order of strengths.
Wednesday, February 27, 2013 at 10:23pm

Chemistry calorimeter.. please help!
A coffee cup calorimeter contains 100ml of .200M H2SO4 at 22.3 degrees Celsius. When 2.16g Mg is added, the temperature rises to 36.3 degrees Celsius. What is the heat of the reaction per mole Mg? Please help and show steps. Much appreciated :)
Wednesday, February 27, 2013 at 10:22pm

Chemistry
How much 5M KOH must be added to 1.0 L of 0.1M glycine (pKa 9.6) at pH 9.0 to bring its pH to exactly 10.0?
Wednesday, February 27, 2013 at 9:48pm

Chemistry
Calculate the mass of baking soda, NaHCO3, needed to neutralize 3.0 mL of 3.0 M hydrochloric acid, HCl(aq). Ok, so I'm super confused. I have the equation, but I'm stuck with what to do with it. Equation: NaHCO3 + HCL --> NaCl + H2O + CO2
Wednesday, February 27, 2013 at 9:34pm

chemistry
determine h30+ in M, of 10.00ml of .100M NaOH after adding 10.00ml of indicator solution?
Wednesday, February 27, 2013 at 9:16pm

Chemistry
Consider the reaction 3Fe(s) + 4H2O(g) ¨ 4H2(g) + Fe3O4(s). If the volume of the container is reduced, 1. more Fe(s) is produced. 2. no change occurs. 3. more H2O(g) is produced. 4. more H2(g) is produced. 5. the equilibrium constant increases.
Wednesday, February 27, 2013 at 9:15pm

chemistry dilution
Given VLP with concentration 200ug/mL, dilute to 3ug/100ul. Please help me with this; many thanks
Wednesday, February 27, 2013 at 8:54pm

Chemistry
At 627ÂºC, sulfur dioxide and oxygen gases combine to form sulfur trioxide gas. At equilibrium, the concentrations for sulfur dioxide, oxygen, and sulfur trioxide gases are .0060M, .0054M, and .0032M, respectively. a. Write a balanced equation for the formation of ...
Wednesday, February 27, 2013 at 8:45pm

Chemistry
Considering the following precip reaction Pb(NO3)2(aq)+2KI(aq)----->PbI2(s)+2KNO3(aq) What is the correct net ionic equation? I think it is 2NO3+^-+2K^+---->2KNO3
Wednesday, February 27, 2013 at 4:07pm

chemistry
If a student attempts to identify an unknown compound by methodused in this experiment. She finds that when she heated a sampleweighing 0.4862 g the mass went down appreciably, to 0.3067 g. Whenthe product was converted to chloride, the mass went up, to 0.3382g. a. Is the ...
Wednesday, February 27, 2013 at 3:48pm

chemistry
what is the temperature (degree celcius) of 1.75g of o2 gas occupying 4.6l at 1.00 atm?
Wednesday, February 27, 2013 at 2:56pm

Chemistry
Calculate the mass of HONH2 required to dissolve in enough water to make 255.5 mL of solution having a pH of 10.02 (Kb = 1.110−8).
Wednesday, February 27, 2013 at 2:45pm

Chemistry
The vapor pressure of pure acetone (propanone) is 266 torr. When a non-volatile solute is added, the vapor pressure of acetone above the solution falls to 232 torr. What is the mole fraction of acetone in the solution? Show work. A) 0.69 B) 0.32 C) 0.13 D) 0.045 E) 0.87
Wednesday, February 27, 2013 at 2:36pm

Chemistry
Isoamyl salicylate (м = 208.25 g/mol) has a pleasant aroma and is used in perfumes and soaps. Which of the following combinations gives a 0.75 m solution of isoamyl salicylate in ethyl alcohol (d = 0.7893 g/mL)
Wednesday, February 27, 2013 at 2:27pm

chemistry
When the concentration of CH3Br and NaOH are both 0.150M, the rate of the reaction is 0.0020M/S. (a) What is the rate of the reaction if the concetration of CH3Br is doubled? _______________M/s (b) What is the rate of the reaction if the concentration of NaOH is halved? ...
Wednesday, February 27, 2013 at 1:49pm

chemistry
A sample of oxygen that occupies 1.00x10^6 mL at 575 mm Hg is subjected to a pressure of 1.36 atm. What will the final volume of the sample be if the temperature is held constant?
Wednesday, February 27, 2013 at 12:49pm

chemistry
How many grams of O2 are needed to produce 45.8 grams of Fe2O3 in the following reaction? 4Fe(s)+3O2(g) - 2Fe2O3(s)
Wednesday, February 27, 2013 at 12:03pm

chemistry
How many grams of ammonium fluoride are required to neutralize 972 'm of 0.00327 M sulfuric acid
Wednesday, February 27, 2013 at 12:03pm

Analytical Chemistry
Calculate the pH at the equivalence point for the titration of 0.160 M methylamine (CH3NH2) with 0.160 M HCl. The Kb of methylamine is 5.0× 10–4. Methylamine is a weak base and reacts with HCl to give the methylammonium ion. HCl + CH3NH2 <---> CH3NH3^+ + Cl^- ...
Wednesday, February 27, 2013 at 11:45am

chemistry
A catalytic converter combines 2.55 g CO with excess O2. What mass of CO2 forms?
Wednesday, February 27, 2013 at 10:24am

Chem
hydrate mean in an inorganic chemistry context
Wednesday, February 27, 2013 at 8:39am

CHEMISTRY
Hydrogen cyanide is used in the production of cyanimid fertilisers. It is produced by the following reaction: 2CH4 + 2NH3 + 3O2  2HCN + 6H2O (a) How much hydrogen cyanide can be produced starting with 100 kg of each of the reactants? (b) Which is the limiting reagent?
Wednesday, February 27, 2013 at 4:18am

Chemistry
This is a back titration question and I'm struggling with it :/ So if you can help me, that would be very appreciated :) Q. A sample of steel wool was dissolved in excess sulfuric acid. The resulting solution (FeSO4 aq) was then titrated with potassium permanganate. 26.5mL...
Wednesday, February 27, 2013 at 4:11am

Chemistry
Mg + HCl ----> MgCl2 + H2 If the water in tube is evaporated , the other product , a white salt remains . Write the balanced chemical equation . Ans: Mg + HCl ----> MgCl2 + H2 + H2O I don't know how to balanced it . I'm confusing where O is in reactants to ...
Wednesday, February 27, 2013 at 3:55am

Chemistry Lab
Hi, I'm doing a lab with acid-base indicators and I'm utterly confused. The lab procedure goes like this: 1) Make your own indicator. 2) set up 12 test tubes and pout a little pH solution into tube. 3) add 4 drops of indicator into each test tube. 4) Estimate the ...
Wednesday, February 27, 2013 at 3:51am

chemistry
What is the structure of H2P2O6??
Wednesday, February 27, 2013 at 3:35am

chemistry
what mass of ammonium chloride is dissolved in 100 grams water in each of the following solutions in 1.10 molal NH4Cl solution, in a solution which is 75% water by mass in solution with a mole fraction of 0.15 NH4Cl? please help me solve this problem. thank you!
Wednesday, February 27, 2013 at 2:57am

chemistry
What's the percentage of the H202 that has been consumed if you use 11.5ml of water, 3.0ml buffer, 2.5ml KI, 1.0ml starch, 1.0ml Na2S203.and 1.0ml H202
Wednesday, February 27, 2013 at 1:21am

chemistry
I am having trouble on this please help Indicate which of these statements is true? For those that are false,.explain why a) addition reactions always involve compounds with multiple bonds b) all addition reactions produce polymers, but not all polymers are addition polymers c...
Wednesday, February 27, 2013 at 12:51am

chemistry
Express your answers as integers separated by commas.
Tuesday, February 26, 2013 at 11:49pm

Chemistry
What volume of 1.60 M SrCL2 is needed to prepare 525 ml of 5.00mM SrCl2?
Tuesday, February 26, 2013 at 11:39pm

college chemistry
during a liquid-liquid extraction the procedure often calls for the use of saturated NaCl when ether is used as the extraction solvent, but not when dichloromethane is used. why?
Tuesday, February 26, 2013 at 11:28pm

chemistry
I need to find the radius of a cylinder with only the following info: Cylinder height=125um There is 1 C atom/0.01848 nm^2 There are 5.75x10^10 C atoms on the surface of cylinder Use quadratic formula to solve
Tuesday, February 26, 2013 at 11:03pm

chemistry
How much heat in joules is required to heat a 44g sample of aluminum from 76 F to 148 F?
Tuesday, February 26, 2013 at 10:13pm

Chemistry
calculate the energy in joules lost when 70.0 grams of water cools from 86.4 celsius to 7.1 celsius
Tuesday, February 26, 2013 at 10:04pm

Chemistry
In a constant-pressure calorimeter, 60.0 mL of 0.320 M Ba(OH)2 was added to 60.0 mL of 0.640 M HCl. The reaction caused the temperature of the solution to rise from 23.24 °C to 27.60 °C. If the solution has the same density and specific heat as water, what is ÄH ...
Tuesday, February 26, 2013 at 9:39pm

chemistry
Commodity prices of NaCl and urea are about $0.033/lb for NaCl (as rock salt) and about $0.10/lb for urea. Calculate the cost of treating 1000 lb of ice on a surface to produce a solution that melts at -3.9 degrees Celsius with each chemical. I know you use to delta T= mkfi ...
Tuesday, February 26, 2013 at 9:24pm

Chemistry
2Al(s)+3Cl2 = 2AlCl3 Limiting Reactant is Cl with 0.329mol. What is the maximum mass of aluminum chloride that can be formed when reacting 30.0g of aluminum with 35.0g of chlorine?
Tuesday, February 26, 2013 at 8:51pm

Chemistry
What is the maximum mass of aluminum chloride that can be formed when reacting 30.0g of aluminum with 35.0g of chlorine
Tuesday, February 26, 2013 at 8:50pm

Chemistry
I have o.236 g for urea and 0.235g for NaCl. And the question is On a gram basis, which is more effective in depressing the freezing point, urea or NaCl? On a mole basis, which Is more effective? I am confused on what depressing the freezing point me and idk how to explain the...
Tuesday, February 26, 2013 at 8:31pm

Chemistry
what is the empirical formula for a compund with 26.2 g N, 7.5 g H, and 66.3 g Cl?
Tuesday, February 26, 2013 at 8:29pm

chemistry
identify the reducing and the oxidizing agent for each reaction: a) 2na + br2 = 2nabr b) h2 + cl2 = 2hcl c) 2li + f2 = 2lif d) s + cl2 = scl2 e) n2 + 2o2 = 2no2 f) mg + cu(no3)2 = mg(no3)2 + cu
Tuesday, February 26, 2013 at 8:26pm

Chemistry
Consider the titration of 25.0mL of 0.10M HAc with 0.10M NaOH. That is, NaOH is added to HAc. (a)pH at the beginning of titration. (b)pH at the equivalence point of the titration. (c) pH at the midpoint of the titration.
Tuesday, February 26, 2013 at 8:00pm

chemistry 1B
1-propanol (P1° = 20.9 Torr at 25 °C) and 2-propanol (P2° = 45.2 Torr at 25 °C) form ideal solutions in all proportions. Let x1 and x2 represent the mole fractions of 1-propanol and 2-propanol in a liquid mixture, respectively, and y1 and y2 represent the mole ...
Tuesday, February 26, 2013 at 7:35pm

Chemistry
Comment on the relative acidities of h3po4 and the h2po4 ion? I don't understand what this question is asking? Would H3PO4 is a strong acid and will completely dissociate into ions in aqueous solution suffice?
Tuesday, February 26, 2013 at 7:33pm

Chemistry
The triprotic acid H3A has ionization constants of Ka1 = 6.8× 10–3, Ka2 = 8.1× 10–9, and Ka3 = 5.0× 10–12. Calculate the following values for a 0.0760 M solution of NaH2A [H+] = ? [H2A-]/[H3A]= ? Calculate the following values for a 0.0760 M ...
Tuesday, February 26, 2013 at 7:25pm

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 0.100 M phosphoric acid solution. pKa1 = 2.16 pKa2 = 7.21 pKa3 = 12.32 [H3PO4] = ? [H2PO4-] = ? [HPO42...
Tuesday, February 26, 2013 at 7:21pm

Chemistry
What fraction of piperazine (perhydro-1,4-diazine) is in each of its three forms (H2A, HA–, A2–) at pH 7.22?
Tuesday, February 26, 2013 at 7:19pm

Chemistry
A certain indicator, HA, has a Ka value of 1.3 × 10-6. The protonated form of the indicator is blue and the ionized form is red. What is the pKa of the indicator? What is the color of this indicator in a solution with pH = 8? Blue, red, or purple?
Tuesday, February 26, 2013 at 7:18pm

chemistry
Calculate the theoretical yield (g) of precipitate formed when 10.0 mL of 0.50 M magnesium nitrate is added to 5.0 mL of 0.50 M potassium phosphate? [You must first write the balanced chemical equation.] Which reactant is present in excess?
Tuesday, February 26, 2013 at 7:04pm

Analytical Chemistry
Show the predominant form of the amino acid tyrosine at pH=13.9 and ph=7.8. Be sure to include the proper number of hydrogens on heteroatoms and the correct formal charges on atoms. I calculated the pka values for COOH (pka=2.41) NH3 (pka=8.67), and OH (pka=11.01) but i'm...
Tuesday, February 26, 2013 at 7:00pm

chemistry
why is HS- a stronger BL base compared to HSO4 In a series of oxybases with the same central atom, the base with more O atoms is stronger. In a series of oxybases with the same central atom, the base with less O atoms is stronger. Since H2SO4 is one of the seven strong acids, ...
Tuesday, February 26, 2013 at 6:32pm

Chemistry
In the formula 2C4H10+13O2=10H2O+8CO2 whats the mass of butane needed to produce 79.7g of carbon dioxide.
Tuesday, February 26, 2013 at 5:49pm

Analytical Chemistry
You prepare a solution from 10.0 mL of 0.100 M MOPS buffer (3-morpholinopropane-1-sulfonic acid) and 10.0 mL of 0.086 M NaOH. Next, you add 1.00 mL of 8.87 × 10-4 M lidocaine to this mixture Denoting lidocaine as L, calculate the fraction of lidocaine present in the form...
Tuesday, February 26, 2013 at 4:25pm

Analytical Chemistry
What fraction of piperazine (perhydro-1,4-diazine) is in each of its three forms (H2A, HA–, A2–) at pH 7.05? Not sure how to find k1 and k2 needed for the fraction formulas...please help :(
Tuesday, February 26, 2013 at 4:13pm

Chemistry
what is the freezing point of 16.7g of LiCl in 136g of water, assuming complete dissociation for water kf= -1.86/mol
Tuesday, February 26, 2013 at 12:31pm

chemistry
what is the structure of H2P2O6?
Tuesday, February 26, 2013 at 11:51am

Chemistry
A block of aluminum with a volume of 98.5 cm3 absorbs 67.4 J of heat. If its initial temperature was 32.5 °C, what is its final temperature? (density of aluminum = 2.70 g/cm3) I do not understand how to get the answer
Tuesday, February 26, 2013 at 11:43am

Chemistry
Identify the true statement about Lewis structures. Select all the correct answers. 1. Hydrogen is usually surrounded by 4 electrons in a valid Lewis structure. 2. A single bond in a Lewis structure represents 2 electrons. 3. A double bond in a Lewis structure represents 2 ...
Tuesday, February 26, 2013 at 11:37am

Chemistry
Using the balanced equation of: HCl+NaOH-->H20+NaCl, how many moles of HCl could be neutralized with 13.2 mL of 3.00 M NaOH?
Tuesday, February 26, 2013 at 8:04am

Chemistry
How many moles of NaOH are in 13.2 mL of 3.00 M NaOH?
Tuesday, February 26, 2013 at 8:02am

Chemistry
Would you expect the pressure of a 12.5 mL syringe of natural gas to be the same as the pressure of 12.5 mL of air? In other words, is Boyle's Law dependent on the type of gas that is being measured?
Tuesday, February 26, 2013 at 7:44am

Chemistry
Are the following electrolytes or non-electrolytes? 1) CH3CH2CH2OH 2) Mg(OH)2 3) H3CO4CH3
Tuesday, February 26, 2013 at 7:33am

Chemistry
How many moles of magnesium sulfate are needed to make in a solution of 0.10g Mg2SO4?
Tuesday, February 26, 2013 at 7:28am

Chemistry
In the reaction 2H2O2(aq)-->2H2O2 + O2 (g), There is intially 0.865 M H2O2. After 10.0 minutes, the molarity of H2O2 changes to 0.792 M. What is the rate of reaction in terms of H2O2?
Tuesday, February 26, 2013 at 5:28am

English
Commas: Do I need a comma between the words notes and so? - "Sitting at the sticky, crumb-covered cafeteria table, Luther and Ruth carefully studied their chemistry notes so that Dr. Wilson's next tricky test wouldn't confuse them." Do I need a comma between ...
Monday, February 25, 2013 at 8:48pm

chemistry
What groups would be ionized in a solution of pH 12
Monday, February 25, 2013 at 8:41pm

Chemistry
at a pressure of 390.0 kPa, a sample of ideal gas containing 110. moles of propane is collected at a tempature of 55 degrees celcius. find the volume of the propane tank used
Monday, February 25, 2013 at 8:32pm

chemistry
a sample of Ag2S has a mass of 62.4g. what mass of each element could be obtained by decomposing this sample?
Monday, February 25, 2013 at 8:23pm

chemistry
heating copper sulfate pentahydrate will evaporate the water from the crystals. leaving anhydrous copper sulfate,. a white powder. what mass of anhydrous CuSO4 would be produced by heating 500.0g of CuSO4*5H2O
Monday, February 25, 2013 at 7:59pm

Chemistry
A 205 mg sample of a diprotic acid is dissolved in enough water to make 250.0 ml of solution. The pH of this solution is 2.15. A saturated solution of calcium hydroxide (Ksp= 1.3 x 10-6) is prepared by adding excess calcium hydroxide to water and then removing the undissolved ...
Monday, February 25, 2013 at 6:27pm

chemistry
calculate the percentage of water in each of the following hydrates SrCl2*6H2O
Monday, February 25, 2013 at 6:09pm

chemistry
which element is the most reactive in group 3? group 4?
Monday, February 25, 2013 at 5:32pm

Chemistry
You have .5g of copper. If the nitric acid is 16 M HNO3, how many milliliters of nitric acid will react exactly with that amount of copper. I know that when I get that volume I will triple it so that there will be excess acid and the copper will be the limiting reactant.
Monday, February 25, 2013 at 5:18pm

Chemistry
You prepare a solution from 10.0 mL of 0.100 M MOPS buffer (3-morpholinopropane-1-sulfonic acid) and 10.0 mL of 0.083 M NaOH. Next, you add 1.00 mL of 5.77 × 10-5 M lidocaine to this mixture Denoting lidocaine as L, calculate the fraction of lidocaine present in the form...
Monday, February 25, 2013 at 4:09pm

Chemistry
if a gas is initially at 1.5 atm of pressure, Occupies a volume of 3.0 L at a tmepeature of 293K, what will be the new volume if the pressure increases to 2.5 atm and is now at 303K?
Monday, February 25, 2013 at 3:41pm

Chemistry
Explain how you would prepare 100.0 mL of 0.500 M NaCl solution. Include the appropriate glassware and calculations.
Monday, February 25, 2013 at 2:57pm

Chemistry
Please show work. 2Al(s) + 2NaOH(aq) + 6H2O(l) ---> 2NaAl(OH)4(aq) + 3H2(g) What mass of hydrogen gas would be formed from a reaction of 2.48 g Al and 4.76 g NaOH in water? Pb(NO3)2(s) + 2NaI(aq) ----> 2PbI2(s) +2NaNo3(aq) (a) If the solution contains 7.00 g NaI, what ...
Monday, February 25, 2013 at 1:49pm

Chemistry Help!!!!!
How many milliliters of 0.635M K2CrO4 are needed to precipitate all the silver in 410mL of 0.158M AgNO3 as AgCrO4 ?
Monday, February 25, 2013 at 1:20pm

Chemistry
A solution containing 0.100 mol of Na2CO3 and 0.100 mol of NiCl2 is allowed to react. What mass of precipitate forms in this reaction? I think I know how to do it but don't understand. Do I figure out the mass of each of the compounds? HELP please!!!
Monday, February 25, 2013 at 12:44pm

Chemistry
A solution containing 0.100 mol of Na2CO3 and 0.100 mol of NiCl2 is allowed to react. What mass of precipitate forms in this reaction? I just don't understand how to get the answer. Can someone please show me and explain to me how to do this.
Monday, February 25, 2013 at 11:21am

Chemistry 132
What is the net ionic equations for Ca Cl2 + Na2 CO3=Ca CO3 + 2Na Cl
Monday, February 25, 2013 at 11:15am

chemistry
Calculate the wavelength of a proton with energy 2.45 eV.
Monday, February 25, 2013 at 10:24am

chemistry
Calculate the wavelength of a photon with energy 2.45 eV.
Monday, February 25, 2013 at 10:16am

chemistry
Which atom or ion would you expect to have the smallest radius? Ne F- Na+ Ne-
Monday, February 25, 2013 at 9:59am

chemistry
How many of the following electron configurations are allowed? 1s22s22p7 1s22s22p62d1 [Ne]4s24p4 [Ar]3d64s2 1s22s22p83s23p4
Monday, February 25, 2013 at 9:55am

chemistry
Calculate the wavelength, λ, in meters of a photon capable of exciting an electron in from the ground state to n = 4.
Monday, February 25, 2013 at 9:46am

chemistry
Determine the minimum electric potential difference (in volts) that must be applied to accelerate an α-particle so that on interaction with a hydrogen atom, a ground state electron will be excited to n = 6.
Monday, February 25, 2013 at 9:36am

chemistry
A photon with a wavelength (λ) of 3.091 x 10–7 m strikes an atom of hydrogen. Determine the velocity (in meters/second) of an electron ejected from the excited state, n = 3.
Monday, February 25, 2013 at 9:31am

Chemistry
you have 20% sucrose solution. you need to mke 100ml of 15% sucrose solution. which is the correct dilution? A. 85ml of 20% sucrose and 15ml of h2o B. 25ml of 20% sucrose and 75ml of h2o C. 75ml of 20% sucrose and 25ml of h2o D. 15ml of 20% sucrose and 85ml of h2o
Monday, February 25, 2013 at 8:29am

Chemistry
At the temperature of 30degree C and pressure of 1*10^5 pa, 30dm3 of H2 gas is burned with 30dm3 of O2 gas in a container of 60dm3. Calculate the pressure different after the complete combustion and cooling upto 30degree C again.
Monday, February 25, 2013 at 8:26am

Chemistry
Biphenyl, C12H10, is a nonvolatile, nonionizing solute that is soluble in benzene, C6H6. At 25 °C, the vapor pressure of pure benzene is 100.84 torr. What is the vapor pressure of a solution made from dissolving 17.3 g of biphenyl in 34.0 g of benzene?
Monday, February 25, 2013 at 4:52am

chemistry
What is the osmotic pressure, expressed in the unit mmH2O, of a solution containing 125 ug of vitamin B12 (C63H88CoN14O14P) in 2.50 mL H2O at 25 degrees C? Answer: 9.33 mmH2O
Monday, February 25, 2013 at 2:32am

Chemistry: Freezing point
An aqueous solution is prepared by dissolving 1.08 g of human serum albumin, a protein obtained from blood plasma, in 50.0 mL of water. The solution has an osmotic pressure of 0.00770 atm at 298 K. What is the molar mass of the albumin? Answer: 6.86 x 10^4 g/mol
Monday, February 25, 2013 at 2:29am

Chemistry
A crystalline white solid is a mixture of glucose (C6H12O6) and sucrose (C12H22O11). Is it possible that a 10.00 g sample of the solid dissolved in 100.0 g H2O might have a freezing point of -1.25 degrees C? Explain. Answer: No. The freezing point would be -1.03 degrees C
Monday, February 25, 2013 at 2:22am

Chemistry
A 1.065-g sample of an unknown substance is dissolved in 30.00 g of benzene; the freezing point of the solution is 4.25 degrees C. The compound is 50.69% C, 4.23% H, and 45.08% O by mass. Info you might need on benzene: Normal Freezing point,degrees C: 5.53 Kf, degrees m^1: 5....
Monday, February 25, 2013 at 2:19am

Chemistry
What mass of sucrose, C12H22O11, should be added to 75.0 g H2O to raise the boiling point to 100.35 degrees C? Molal boiling point of water: 0.512 Kb, degrees C m^-1 Answer: 18 g sucrose
Monday, February 25, 2013 at 2:12am

Chemistry
What is the freezing point of a soluton is which 10.0 g of naphthalene [C10H8(s)] is dissolved in 50.0 g of benzene [C6H6(l)]? Extra info you might need: benzene= 5.12 degrees C m^-1 Answer should be: -2.46
Monday, February 25, 2013 at 2:08am

Chemistry
Nitrocellulose lacquer is used as a protective coating on wood. What mass of nitrocellulose is contained in one gallon (3.8L) of lacquer that is 5.1% nitrocellulose by mass? The density of the lacquer is 0.79 g/mL.
Monday, February 25, 2013 at 2:04am

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