Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

chemistry
A glass of composition 85% SiO2 - 15% K2O is to be surface strengthened by ion exchange. To this end, two identical specimens approximately the size and shape of credit cards are soaked for the same amount of time at 850 ∘C. Sample A is soaked in NaCl and sample B is ...
Saturday, April 13, 2013 at 5:48am

chemistry
Please mark below all of the statments that correctly describe the physical properties of glass. Glasses do not have slip systems. Glasses consist of both covalent and ionic bonding. Glasses are brittle at room temperature. Glasses are amorphous and have no long range symmetry...
Saturday, April 13, 2013 at 5:48am

chemistry
Which of the following statements describes why ion exchange of 99% SiO2 - 1% B2O3 in a salt bath of molten postassium chloride (KCl) is not an effective way to increase the surface strength of the glass sample? The ion exchange works correctly, however both air-cooling and ...
Saturday, April 13, 2013 at 5:46am

chemistry
In the following reaction, how many grams of ferrous sulfide (FeS) will produce 0.56 grams of iron (III) oxide (Fe2O3)? 4FeS + 7O2 d 2Fe2O3 + 4SO2 The molar mass of ferrous sulfide is 87.92 grams and that of iron (III) oxide is 159.7 grams.
Saturday, April 13, 2013 at 2:58am

Chemistry
Consider the equilibrium 2NO (g) <---> 2NO (g) + Cl2 (g). In a 1 L container @ equilibrium there are 1.0 mol NOCL, 0.70 mol NO, and 0.40 mol Cl2. @ constant temperature and volume, 0.10 mol NaCl is added. What are the concentrations in the "new" equilibrium in ...
Friday, April 12, 2013 at 11:22pm

chemistry
What is the difference between e/z notation and cis-trans isomerism?
Friday, April 12, 2013 at 9:43pm

chemistry
Please mark below all of the statments that correctly describe the physical properties of glass. Glasses do not have slip systems.Glasses consist of both covalent and ionic bonding.Glasses are brittle at room temperature.Glasses are amorphous and have no long range symmetry....
Friday, April 12, 2013 at 7:32pm

chemistry
Consider two glasses. Glass A has a composition of 5% CaO - 95% B2O3. Glass B has a composition of 15% CaO - 85% B2O3. Both samples are cooled from their molten state to room temperature at rates that result in an identical glass transition temperature. Given this information...
Friday, April 12, 2013 at 7:24pm

chemistry
Which of the following statements describes why ion exchange of 99% SiO2 - 1% B2O3 in a salt bath of molten postassium chloride (KCl) is not an effective way to increase the surface strength of the glass sample? a -The ion exchange works correctly, however both air-cooling and...
Friday, April 12, 2013 at 6:50pm

chemistry
A glass of composition 85% SiO2 - 15% K2O is to be surface strengthened by ion exchange. To this end, two identical specimens approximately the size and shape of credit cards are soaked for the same amount of time at 850degreeC. Sample A is soaked in NaCl and sample B is ...
Friday, April 12, 2013 at 6:36pm

chemistry
Which of these processes will lower the glass transition temperature of a glass? Increase the cooling rate, Decrease the cooling rate, Increase amount of network modifier, Decrease amount of network modifier, Quench the glass to cool the surfaces quickly, Decrease the number ...
Friday, April 12, 2013 at 6:16pm

chemistry
How many moles of sodium hydroxide are needed to react with 148.0 g of Iron (III) bromide?
Friday, April 12, 2013 at 1:21pm

Chemistry
The pH of an 0.0870 M solution of weak acid A is 2.20. The pH of an 0.0830 M solution of weak acid B is 4.07. The pH of an 0.0890 M solution of weak acid C is 5.13. Identify the three acids from among those listed below (the Ka values are listed in Appendix E of your textbook...
Friday, April 12, 2013 at 12:46pm

ap chemistry
The volume of 0.100 mol of helium gas at 34°C is increased isothermally from 1.00 L to 4.50 L. Assuming the gas to be ideal, calculate the entropy change for the process.
Friday, April 12, 2013 at 10:07am

College Chemistry
For each trial, enter the amount of heat lost by the calorimeter, qcalorimeter. Be careful of the algebraic sign here and remember that the change in temperature is equal to the final temperature minus the initial temperature. Report your answer using 4 digits. Note, this is 1...
Friday, April 12, 2013 at 5:39am

Chemistry
Calculate E°cell (in volts) for a fuel cell that employs the reaction between methane gas and oxygen to form carbon dioxide and water. (to 4 significant figures) ∆G⁰f for CH4 = -50.5 kJ/mol ∆G⁰f for CO2 = -394.4 kJ/mol F = 96485/mol e- I got 0.4455 ...
Friday, April 12, 2013 at 4:09am

chemistry
Monosodium glutamate (aka MSG) NaC5H8NO4 is used as a food additive for flavor or as a preservative. a. what is the mass of MSG (g) that contains 545 mg sodium? b. calculate the percentage of each element present in MSG.
Friday, April 12, 2013 at 2:25am

chemistry
A sample of hematite Fe2O3 has the mass 4.83 x 10 3 kg. a. how much iron (kg) can be extracted from this sample of hematite? b. what is the percentage of iron in this ore?
Friday, April 12, 2013 at 2:21am

chemistry
A student needs to use a 0.750 mol sample of (NH4)2SO3 for an experiment: a. how many grams does she need to weigh out? b. how many formula units are in the sample?
Friday, April 12, 2013 at 2:19am

Chemistry
Potassium hypobromite, KOBr, converts ammonia to nitrogen by the following reaction. 3KOBr + 2NH3 N2 + 3KBr + 3H2O To prepare 448.2 mL of dry N2, when measured at 22.3 °C and 777.3 torr, what is the minimum number of grams of KOBr required?
Friday, April 12, 2013 at 2:14am

Chemistry
How many grams of NaF should be added to 612 ml of 0.4 M HF (Ka = 6.8 x 10-4) to produce a buffer solution where pH = 3.10?
Friday, April 12, 2013 at 1:48am

Chemistry
An unknown amount of gas occupies 30.0 L at 2.1 atm and 298K. How many moles does the sample contain? What is the mass if the gas is helium? What is the mass if the gas is argon?
Friday, April 12, 2013 at 1:15am

Chemistry
If N2 is added to a balloon that contains O2 (partial pressure 450 mm Hg) and CO2 (partial pressure 150 mm Hg) to give a total pressure of 850 mm Hg, what is the partial pressure of each gas in the final mixture?
Friday, April 12, 2013 at 1:14am

Chemistry
Using the given boiling points, predict which compound has the higher vapor pressure at a given temperature. A. ethanol (C2H6O, bp 78 degrees C) or 1-propanol (C3H8O, bp 97 degrees C) B. hexane (C6H14, bp 69 degrees C) or octane (C8H18, bp 125 degrees C)
Friday, April 12, 2013 at 1:11am

Chemistry
A student in lab gathered temperature and concentration data for the solubility of borax and generated a plot of ln(Ksp) vs. 1/T having the equation of the line y = -11655x + 35.585. Determine the temperature (in units of K) at which the reaction becomes spontaneous.
Thursday, April 11, 2013 at 10:56pm

Chemistry
How much energy would be released when 675 grams of steam is condensed to water
Thursday, April 11, 2013 at 10:28pm

chemistry
I did an experiment today called "removing tarnish". we removed tarnish from a fork wrapped in foil paper. Now i have to answer some questions. please correct me if i answer them wrong. im not the best in chemistry. thanks. 1. describe the odor of the water trapped ...
Thursday, April 11, 2013 at 9:27pm

10th grade chemistry
How many grams of kno3 can be dissolved in 100g of h2o at 50°c
Thursday, April 11, 2013 at 8:46pm

Chemistry
The Ka of a monoprotic weak acid is 4.47 × 10-3. What is the percent ionization of a 0.184 M solution of this acid?
Thursday, April 11, 2013 at 8:36pm

Chemistry
A 10 mL sample of 1.5 M Potassium Phosphate is placed in a 100 mL volumetric flask and diluted to the mark. What is the Molar concentration of Potassium ions in this diluted solution?
Thursday, April 11, 2013 at 8:29pm

Chemistry
20.00mL of a 1.100E-4 mol/L Pb(NO3)2 is mixed with 80.00mL of 4.450E-2 mol/L CaI2. Will a precipitate form? Here's what I did... [Pb2+] c=n/v = (1.1E-4 mol/L x 0.02L)/(0.02L + 0.08L) = 2.2E-5 mol/L [I-] c=n/v = (4.45E-2 mol/L x 0.08L)/0.1L = 3.56E-2 mol/L Qsp = [Pb2+][I...
Thursday, April 11, 2013 at 6:41pm

Chemistry
I need help starting this question... A buffer solution is prepared by adding 30.0g of pure acetic acid to 41.0g of sodium acetate in water, and then diluting the solution to 1.00L. What is the pH of the buffer solution?
Thursday, April 11, 2013 at 6:29pm

chemistry
you heat 4.31 grams of a nickel 2 phosphate hydrate. You heat to a constant mass of 3.09 grams. What is the formula of this hydrate?
Thursday, April 11, 2013 at 5:46pm

Analytical Chemistry
A solution prepared by mixing 51.4 mL of 0.340 M AgNO3 and 51.4 mL of 0.340 M TlNO3 was titrated with 0.680 M NaBr in a cell containing a silver indicator electrode and a reference electrode of constant potential 0.175 V. The reference electrode is attached to the positive ...
Thursday, April 11, 2013 at 3:32pm

Chemistry
You extract the iron from a tablet and dilute that to 250.0 ml in a volumetric flask. You transfer 0.400 ml of this solution to a 25.0 ml volumetric flask and dilute this to volume. When you measure the concentration of this solution, you find that it is 3.27 ppm Fe. How many ...
Thursday, April 11, 2013 at 2:31pm

Chemistry
1. Which of the following compounds is an unsaturated hydrocarbon? methane *propyne nonane methyl 2. The general name for hydrocarbons with at least one triple covalent bond is ____. alkenes alkyls alkanes *alkynes 3. What is the name of the smallest alkyne? butyne *ethyne ...
Thursday, April 11, 2013 at 2:04pm

Chemistry: Please check answers
1. Which of the following compounds is an unsaturated hydrocarbon? methane *propyne nonane methyl 2. The general name for hydrocarbons with at least one triple covalent bond is ____. alkenes alkyls alkanes *alkynes 3. What is the name of the smallest alkyne? butyne *ethyne ...
Thursday, April 11, 2013 at 1:16pm

chemistry
A student estimated the volume of a liquid in a beaker to be 300 mL. When she poured the liquid into a graduated cylinder, she measured the volume as 295 mL. Considering the measurement in the graduated cylinder to be the accepted value, what is the percent error of the ...
Thursday, April 11, 2013 at 12:05pm

chemistry
Cathode = Cu2(s) + 2e- ¨ Cu(s) Anode = 2H2O(l) ¨ O2(g) + 4H(g) + 4e- Net = Cu2(s) + 2H2O(l) ¨ Cu(s) + O2(g) + 4H(g) the minimum voltage that must be supplied to electrolyze aqueous copper(II) sulfate
Thursday, April 11, 2013 at 11:42am

Chemistry
What is the formula for CoCl2 with 45.5 percent water?
Thursday, April 11, 2013 at 11:38am

Chemistry
How many grams of co2 are in 3.92 times 10 to the 24th molecules
Thursday, April 11, 2013 at 9:36am

Chemistry
How many milliliters water are needed to make a 0.171 M solution that contains 1.00 g of NaCl?
Thursday, April 11, 2013 at 7:55am

Chemistry
Which of these processes will lower the glass transition temperature of a glass? 1 - Increase the cooling rate 2 - Decrease the cooling rate 3 - Increase amount of network modifier 4 - Decrease amount of network modifier 5 - Quench the glass to cool the surfaces quickly 6 - ...
Thursday, April 11, 2013 at 5:46am

chemistry
Please i tried to give this answer on a quiz but it was not accepted. To name this alkane: CH3CH2CH2CHCH3 with a substituent of CH3 on 2nd carbon.
Thursday, April 11, 2013 at 1:05am

Chemistry
How many liters are in .005 moles?
Wednesday, April 10, 2013 at 11:23pm

Chemistry
How much energy in kilocalories is needed to vaporize 255g of water? The heat of vaporization of water is 540 cal/g.
Wednesday, April 10, 2013 at 11:14pm

Chemistry
What volume does 3.01 x 10^21 molecules of N2 occupy at STP?
Wednesday, April 10, 2013 at 11:06pm

chemistry
a salt shaker filled with 17.0g sodium chloride contain how many moles?
Wednesday, April 10, 2013 at 10:54pm

Chemistry 1301
How many g of NaOH are in 10 ml 0.1 M solution? How do you find this out, what are the steps?
Wednesday, April 10, 2013 at 8:58pm

Chemistry
Enough of a monoprotic acid is dissolved in water to produce a 1.47 M solution. The pH of the resulting solution is 2.64. Calculate the Ka for the acid.
Wednesday, April 10, 2013 at 8:54pm

Chemistry
Describe how you would prepare 2.00 L of an aqueous solution having a pH of 3.60 if you had a supply of 0.100 M HCL
Wednesday, April 10, 2013 at 8:24pm

chemistry
Sodium phosphate dodecahydate reacts with barium chloride dihydrate. If Na2SO4 is an unkown contaminant of sodium phosphate dodecahydrate, how does it presence affect yeild of sodium phosphate in the exexpiriment?
Wednesday, April 10, 2013 at 7:57pm

chemistry
Sodium phosphate dodecahydate is reacts with barium chloride dihydrate.barium phosphate is lost during filtering will the percent limiting reactant be hihg or low?
Wednesday, April 10, 2013 at 7:51pm

Chemistry
ph of a 0.234 m nahco3 solution look up the appropriate ka or kb value
Wednesday, April 10, 2013 at 7:35pm

Chemistry
The reaction for the formation of gaseous hydrogen fluoride from hydrogen and fluorine has an equilibrium constant of 1.15x10^2 at a given temperature. In a particular experiment, 3.0 mol of each component was added to a 1.5 L flask. What is the equilibrium concentration of ...
Wednesday, April 10, 2013 at 7:15pm

Chemistry
1.Write an equilibrium constant equation for the following reaction: 4NH3(g)+5O2(g)= 4NO(g)+6H2O(g) 2. What does the above [] mean in the above equation?
Wednesday, April 10, 2013 at 4:34pm

chemistry
calculate the solubility of SrSO4 in A: pure water B: 0.045 M Sr(NO3)2 C: 0.05 M NaCl D: 0.016 M ZnCl2
Wednesday, April 10, 2013 at 2:48pm

chemistry
nitrogen gas reacts with hydrogen gas to form ammonia. The nitrogen gas is in a closed 500.0 mL flask at 751 mm HG connected to a 1.25 L flask containing the hydrogen gas at 1.21 atm pressure. Both flasks are kept at 37C. if the stopcock is opened and the gases are allowed to ...
Wednesday, April 10, 2013 at 2:40pm

Chemistry
A buret is partially filled with NaOH solution, to a volume of 1.14 mL. A 20-mL sample of 0.1011 M HCl is titrated to a faint pink phenolphthalein endpoint. The final buret reading is 22.37 mL. What is the molartiy of the NaOH solution?
Wednesday, April 10, 2013 at 1:17pm

Chemistry
A gaseous mixture contains 436.0 Torr of H2(g), 341.5 Torr of N2(g), and 79.7 Torr of Ar(g). Calculate the mole fraction, X, of each of these gases.
Wednesday, April 10, 2013 at 12:12pm

chemistry
A solution of household bleach contains 5.25% sodium hypochlorite, NaOCl, by mass. Assuming that the density of bleach is the same as water, calculate the volume of household bleach that should be diluted with water to make 500.0 mL of a pH = 10.23 solution.
Wednesday, April 10, 2013 at 11:58am

chemistry
The Ka of a monoprotic weak acid is 7.25 × 10-3. What is the percent ionization of a 0.167 M solution of this acid? If the concentration is more than 1000 times greater than the Ka, then you can make an assumption that simplifies the algebra needed to solve the problem. ...
Wednesday, April 10, 2013 at 11:57am

chemistry
The half-equivalence point of a titration occurs half way to the end point, where half of the analyte has reacted to form its conjugate, and the other half still remains unreacted. If 0.460 moles of a monoprotic weak acid (Ka = 3.8 × 10-5) is titrated with NaOH, what is ...
Wednesday, April 10, 2013 at 11:55am

chemistry
A flask contains 0.342 g of acid and a few drops of phenolphthalein indicator dissolved in water. The buret contains 0.120 M NaOH. 20.f mL of base is needed to reach the endpoint of the titration. Assuming that the acid is monoprotic, what is the molar mass?
Wednesday, April 10, 2013 at 11:53am

chemistry
Which of these processes will lower the glass transition temperature of a glass? 1 - Increase the cooling rate 2 - Decrease the cooling rate 3 - Increase amount of network modifier 4 - Decrease amount of network modifier 5 - Quench the glass to cool the surfaces quickly 6 - ...
Wednesday, April 10, 2013 at 10:55am

Chemistry
What quantity of heat is required to flow into 1.50 g of water at 18.0 degrees Celsius that is heated in an electric kettle to 70.0 degrees Celsius?
Wednesday, April 10, 2013 at 10:21am

Chemistry
A glass of composition 85% SiO2 - 15% K2O is to be surface strengthened by ion exchange. To this end, two identical specimens approximately the size and shape of credit cards are soaked for the same amount of time at 850 ∘C. Sample A is soaked in NaCl and sample B is ...
Wednesday, April 10, 2013 at 10:06am

Chemistry
55 kJ of heat are added to 200 kg of a metal at 28.00◦C and the temperature rises to 29.18◦C. What was the metal? 1. tungsten (speciﬁc heat = 0.134 J/g · ◦ C) 2. copper (speciﬁc heat = 0.385 J/g · ◦ C) 3. silver (speciﬁ...
Wednesday, April 10, 2013 at 10:04am

Chemistry
Which of these processes will lower the glass transition temperature of a glass? 1.Increase the cooling rate 2.Decrease the cooling rate 3.Increase amount of network modifier 4.Decrease amount of network modifier 5.Quench the glass to cool the surfaces quickly 6.Decrease the ...
Wednesday, April 10, 2013 at 10:04am

chemistry
what is the mass of LiF is needed to produce 2.5 L of a .30 M solution
Wednesday, April 10, 2013 at 9:45am

chemistry
For reactions in solution, molar concentrations are usually used in equilibrium constant expressions (designated by K or Kc). In gases, partial pressures can also be used (designated by Kp). Equilibrium partial pressures of NOCl, NO and Cl2 in a container at 300 K are 1.2 atm...
Wednesday, April 10, 2013 at 9:31am

chemistry
Hydrogen iodide reacts with itself to give hydrogen and iodine. The equilibrium constant is about 2.0 x 10─3 at a particular temperature. If you were to place some hydrogen iodide in a container and seal the container, what would you expect to find at equilibrium: mostly...
Wednesday, April 10, 2013 at 9:30am

chemistry
Which of the following statements describes why ion exchange of 99% SiO2 - 1% B2O3 in a salt bath of molten postassium chloride (KCl) is not an effective way to increase the surface strength of the glass sample? a) The ion exchange works correctly, however both air-cooling and...
Wednesday, April 10, 2013 at 8:59am

chemistry
Which of these processes will lower the glass transition temperature of a glass? a) Increase the cooling rate b) Decrease the cooling rate c) Increase amount of network modifier d) Decrease amount of network modifier e) Quench the glass to cool the surfaces quickly f) Decrease...
Wednesday, April 10, 2013 at 8:52am

chemistry
Which of these processes will lower the glass transition temperature of a glass? a)Increase the cooling rate b)Decrease the cooling rate c)Increase amount of network modifier d)Decrease amount of network modifier e)Quench the glass to cool the surfaces quickly f)Decrease the ...
Wednesday, April 10, 2013 at 8:41am

chemistry
A glass of composition 85% SiO2 - 15% K2O is to be surface strengthened by ion exchange. To this end, two identical specimens approximately the size and shape of credit cards are soaked for the same amount of time at 850 C. Sample A is soaked in NaCl and sample B is soaked in ...
Wednesday, April 10, 2013 at 8:40am

chemistry
Which of the following statements describes why ion exchange of 99% SiO2 - 1% B2O3 in a salt bath of molten postassium chloride (KCl) is not an effective way to increase the surface strength of the glass sample? a)The ion exchange works correctly, however both air-cooling and ...
Wednesday, April 10, 2013 at 8:39am

chemistry
In which of the following ways would you change the glass sample to make the ion exchange more efficient? a)Change the composition of the glass to increase the proportion of B2O3. b)Change the composition of the glass to add Na2O, Li2O, or MgO. c)Change the composition of the ...
Wednesday, April 10, 2013 at 8:38am

chemistry
Please mark below all of the statments that correctly describe the physical properties of glass. a)Glasses do not have slip systems. b)Glasses consist of both covalent and ionic bonding. c)Glasses are brittle at room temperature. d)Glasses are amorphous and have no long range ...
Wednesday, April 10, 2013 at 8:37am

chemistry
Consider two glasses. Glass A has a composition of 100% SiO2. Glass B has a composition of 25% Na2O - 75% SiO2. (a) Which sample has a shorter average bond length (r)? (b)Which sample has a higher thermal expansion coefficient? (c) Which sample has a lower viscosity?
Wednesday, April 10, 2013 at 8:33am

chemistry
Sulfur and chlorine can react together to form S2Cl2. When 1.00g of this sulfur chloride reacted with water, 0.36g of a yellow ppt of sulfur was formed together with a solution contianing a mixture of sulfurous acid, H2SO3, and HCl acid. Use the above data to deduce the ...
Wednesday, April 10, 2013 at 4:54am

Chemistry
1-Octene --H2PtCl6--> --NaBH4, C2H5OH, HCl(6M)--> n-Octane How many moles of hydrogen are used to convert the precatalyst to the catalyst? What volume of H2 gas does this correspond to at STP?
Wednesday, April 10, 2013 at 3:28am

Chemistry
An unknown amount of gas occupies 30.0 L at 2.1 ATM and 298K. How many moles does the sample contain? What is the mass if the gas is helium? What is the mass if the gas is argon?
Wednesday, April 10, 2013 at 1:50am

Chemistry
what volume does 3.01x 10^21 molecules of N2 occupy at STP
Wednesday, April 10, 2013 at 1:47am

General Chemistry II
Also, not sure if I did this correctly: Compute the solubility in moles/ liter for each sample titrated. 2.3 g KHTar in water. 2.3/18= .128 S= (.128/0.05)= 2.56 moles/ liter Is this correct?
Wednesday, April 10, 2013 at 1:29am

General Chemistry II
Why is the Ksp value larger for NaNO3 and KNO3 than water?
Wednesday, April 10, 2013 at 1:25am

Chemistry - DrBob Help!
Draw product for chlorination of 2methylbutane through a 2nd radical
Wednesday, April 10, 2013 at 12:26am

chemistry
An automobile tire contains air at a pressure of 200. kPa and 25°C. The tire and its air heat up during traveling. If the pressure increases to 250. kPa but the volume remains the same, what is the temperature of the air inside the tire?
Tuesday, April 9, 2013 at 11:10pm

Chemistry
One cubic meter of ideal diatomic gas is expanded from 150oC, 8 bar isothermally to the final volume. The gas is then cooled at constant volume until 50oC and 3 bar. Calculate the total change in work, heat, enthalpy, and internal energy.
Tuesday, April 9, 2013 at 10:36pm

chemistry
If 8.72 grams of oxalic acid, H2C2O4, a diprotic acid, is neutralized when 23.4 mL of a solution of KOH is added, what is the molarity of KOH? the topic is acid-base triation, and i have already converted the mass to moles,but I am having trouble finding the volume for the ...
Tuesday, April 9, 2013 at 10:10pm

Chemistry equation
Write a correctly balanced series of chemical equations to describe the stepwise protonation of carbonate ion. Na2CO3 with HCl
Tuesday, April 9, 2013 at 9:59pm

chemistry
What would the boiling point be of 300 ml with 40 g CuCl2 dissolved in it?
Tuesday, April 9, 2013 at 9:59pm

chemistry
What would the boiling point be of 300 ml with 40 g CuCl2 dissolved in it?
Tuesday, April 9, 2013 at 9:49pm

chemistry
Aspirin, C 9 H 8 O 4 , slowly decomposes at room temperature by reacting with water in the atmosphere to produce acetic acid, HC 2 H 3 O 2 , and 2-hydro x ybenzoic acid, C 7 H 6 O 3 (this is why old bottles of aspirinoften smell like vinegar):C 9 H 8 O 4 + H 2 O p HC 2 H 3 O ...
Tuesday, April 9, 2013 at 9:35pm

chemistry
calculate the pH of a 0.50 m solution of HCN. Ka for HCN is 4.9*10^-10 (The chemical equation for this.)
Tuesday, April 9, 2013 at 9:27pm

Chemistry
If the temperature of 150.0g of water increased from 23.3C to 44.8C, how much heat was absorbed
Tuesday, April 9, 2013 at 9:24pm

chemistry
find the mass in grams of a molecule of aspirin c9h8o4
Tuesday, April 9, 2013 at 9:06pm

Clinical Chemistry
I have 2 questions relating to clinical chemistry... 1st: I have no idea where to even start with this. It seems like it should be simple, but I have no clue. The question is... "In serum, about 55% of total serum calcium is bound. The measurement of ionized (free) ...
Tuesday, April 9, 2013 at 8:57pm

chemistry 1 help please!
Write a chemical equation that shows how acid rain H2SO3 was produced from SO2 gas and water in a zip sealed bag? My chem. teacher never explained how to do this and I have several other questions on this type of subject. If you could help me out it would help me tremendously...
Tuesday, April 9, 2013 at 8:22pm

Clinical Chemistry
This one seems like an easy question but I don't know where to start. Please help! In serum, about 55% of total serum calcium is bound. The measurement of ionized (free) calcium with an ISE is 1.10 mM. What is an estimate of the total calcium in this specimen?
Tuesday, April 9, 2013 at 8:21pm

Chemistry
Okay, I feel like this question should be really easy because it's a multiple choice question but how do you figure it out?? I'm completely drawing a blank. Consider the following equilibrium N2O4(g) <-> 2NO2(g) Kc = 4.8E-3 Which set of concentrations represents ...
Tuesday, April 9, 2013 at 7:07pm

Chemistry
What mass of silver can be produced by reacting 0.300 L of 0.100 M AgNO3 with an excess of Mg?
Tuesday, April 9, 2013 at 6:43pm

Chemistry
I'm reviewing for a test and I'm on Le Chatelier's principle. Decreasing the temperature of an exothermic reaction shifts the equilibrium to the right? I understood this weeks ago but now I can't remember. Wouldn't decreasing the temperature cause there to ...
Tuesday, April 9, 2013 at 6:08pm

Clinical Chemistry
Why is slightly higher serum sodium consistently found by evaluation by ion-selective electrode (ISE) as compared to flame photometry?
Tuesday, April 9, 2013 at 6:00pm

chemistry
How do I calculate the theoretical yield of a catalytic hydrogenation? I have the #s, I just have no idea how to apply it. It's 1-Octene --H2PtCl6--> n-Octane.
Tuesday, April 9, 2013 at 5:59pm

Chemistry
fumes were allowed to escape from the crucible. (what is the composition of the fumes )
Tuesday, April 9, 2013 at 5:59pm

Chemistry: Please check answers
12. What balances charges that may build up as reduction and oxidation occur in a voltaic cell? *the salt bridge one of the half-cells the electrolyte solutions the moving electrons 13. What is the electrode in the center of the most common dry cell made of? copper zinc iron *...
Tuesday, April 9, 2013 at 5:48pm

Chemistry: please check
At which electrode does oxidation occur in a voltaic cell? anode only cathode only *both anode and cathode either anode or cathode, depending on the metal Thank You.
Tuesday, April 9, 2013 at 5:43pm

Chemistry
In a zinc-copper cell, Zn | Zn+2(1M) || Cu+2(1M) | Cu, which electrode is negative? a. Cu(s) b. Zn(s) c. Zn+2(aq) d. Cu+2(aq) Its A or C. Not sure. Please help.
Tuesday, April 9, 2013 at 5:35pm

Chemistry
How long does it take (in minutes) for light to reach Jupiter from the Sun, a distance of 8.258 × 108 km?
Tuesday, April 9, 2013 at 5:28pm

Chemistry
Which of the following result in buffered solutions when equal volumes of the two solutions are mixed? a.) .1 M HCl and .1 M NH4Cl b) .1 M HCl and .1 M NH3 c.) .2 HCl and .1 M NH3 d.) .1 M HCl and .2 M NH3 By def. I know that a buffed solution is made from a weak base and it&#...
Tuesday, April 9, 2013 at 5:19pm

chemistry
In the experiment you have added 50.0 mL of Ni(H2O)6 2+ to the calorimeter. To this you add 5.0 mL of ethlylenediamine and measure the change in temperature of the solution as the reaction proceeds. The temperature increases by 3.4 oC. Calculate the enthalpy (H) for ...
Tuesday, April 9, 2013 at 5:19pm

Chemistry
The question is: what is the ratio [NH3/[NH4+] in an ammonia/ammonium chloride buffer solution with pH= 10.00? (pKa for ammonia=9.25) When working the problem, I tried to solve it a bit backwards, in that I plugged in each of the multiple choices I was given to see which would...
Tuesday, April 9, 2013 at 5:12pm

Chemistry
I have no idea where to even start with this. It seems like it should be simple, but I have no clue. The question is... "In serum, about 55% of total serum calcium is bound. The measurement of ionized (free) calcium with an ISE is 1.10 mM. What is an estimate of the total...
Tuesday, April 9, 2013 at 5:04pm

College Chemistry
You weigh a sample of a monoprotic unknown acid and dissolve it in 50.00 mL of distilled water. Exactly half of this solution is titrated with Sodium Hydroxide to the phenolphthalein end point. The pH of the other half of the original solution is measured with a pH meter. The...
Tuesday, April 9, 2013 at 4:31pm

Chemistry
A 0.750 g sample of an unknown solid is dissolved in 100 mL of water and acidfied with 25 mL of 3 M H2SO4 then titrated with a 0.0200 M KMnO4 solution. If the unknown solid requires 12.5 mL of the KMnO4 solution to reach the endpoint, what is the % sodium oxalate in the ...
Tuesday, April 9, 2013 at 3:54pm

Chemistry
At what temperature does 150 mL of n2 at 300 K and 1.13 atm occupy a volume of 550 mL at a pressure of 1.89 atm?
Tuesday, April 9, 2013 at 3:00pm

Chemistry
Calculate volume of 6MHCL required to prepare a 250 ml of a 0.15MHCL solution??
Tuesday, April 9, 2013 at 2:32pm

Chemistry
Calculate volume of 6MHCL required to prepare a 250 ml of a 0.15MHCL solution??
Tuesday, April 9, 2013 at 2:19pm

chemistry
How many grams of dichloromethane result from reaction of 1.60 of methane if the yield is 48.8 ?
Tuesday, April 9, 2013 at 2:14pm

chemistry
Calculate the mass of co2 produced when 2ch3oh mixed with o2. Given that 2ch3oh is 4o grams and o2 is 46 grams.
Tuesday, April 9, 2013 at 12:53pm

chemistry
Calculate the mass of co2 produced when 2ch3oh mixed with o2. Given that 2ch3oh is 4o grams and o2 is 46 grams.
Tuesday, April 9, 2013 at 12:42pm

chemistry
When 86.7 g of water at a temperature of 73 °C is mixed with an unknown mass of water at a temperature of 22.3 °C the final temperature of the resulting mixture is 61.7 °C. What was the mass of the second sample of water? (Specific heat of water 4.184 J·g-1&...
Tuesday, April 9, 2013 at 11:26am

Chemistry
Between Mg and Zn which one is the anode and which one is the cathode? And between Mg and Fe which one is the anode and which one is the cathode? Please help!!
Tuesday, April 9, 2013 at 11:19am

chemistry
calculate the L of 5.00 M HCI required to neutralize 500.0 mL of 1.00 M Ca (OH)2
Tuesday, April 9, 2013 at 9:37am

Chemistry
When looking at a titration curve, I have to determine which is false and I have it narrowed down to two options: The initial starting point on the titration curve is where pH depends only on [HA]0 or The finial point on a titration curve the pH depends only on [A-] I would ...
Tuesday, April 9, 2013 at 12:16am

AP Chemistry
An unknown metal M forms a soluble compound, M(NO3)2. A solution of M(NO3)2 is electrolyzed. When a constant current of 2.5 amperes is applied for 35 minutes, 3.06 grams of the metal M is deposited. Calculate the molar mass of M and identify the metal.
Monday, April 8, 2013 at 11:30pm

chemistry
200g of HOCl is placed inside a 3L container and allowed to reach equilibrium. Find the equilibrium concentrations for all species. Given: 2HOCL (g) <--> H20 (g) + Cl20 (g) when Delta H = +56 kJ and Keq = 11.11 at 25 C
Monday, April 8, 2013 at 10:50pm

Chemistry
A cell has a standard emf of +0.177 V at 298 K. What is the value of the equilibrium constant for the cell reaction a) if n=1? b) if n=2?
Monday, April 8, 2013 at 10:45pm

chemistry
how do i predict a conjugate a base? Ex: HBr. The conjugate base is Br- a. NH4+ b. H2O c. H2PO4
Monday, April 8, 2013 at 10:02pm

chemistry
A sample of solid sulfur is heated with an electrical coil. If 105 joules of energy is added to a 12.4 gram sample initially at 24.4°C, what is the final temperature of the sulfur?
Monday, April 8, 2013 at 9:53pm

Chemistry
The experimentally measured and generally accepted value for the molar volume of Na is about 23 cm3/mol. Which of the following best explains why the value calculated in Part B is significantly smaller than the measured values? Part B Answer 16.3 cm3/mol Which one would it be...
Monday, April 8, 2013 at 9:23pm

Chemistry
A sample of sucrose, C12H22O11(s),contains 0.16 mol of oxygen, atoms(O). a.) What amount in moles of sucrose is in the sample? b.)How many atoms of carbon are in the sample?
Monday, April 8, 2013 at 9:17pm

chemistry
comment that enthalpy of nutralization is merely the heat of formation one-one mole of liquid water
Monday, April 8, 2013 at 8:43pm

Chemistry
The Ksp for nickel(II) hydroxide is 5.47E-16. What is the base dissociation constant for nickel(II) hydroxide? So I started off doing Ni(OH)2 (s) <-> Ni2+ (aq) + 2OH- (aq) I ..........................0 .................0 C ........................+x ................+2x E...
Monday, April 8, 2013 at 8:41pm

Chemistry
a sample of helium gas has a volume of 1.25L at -125celcius and 50.0atm. the gas is compressed at 50.0 atm to volume of 325ml. what is the final temperature of the helium gas in Celcius
Monday, April 8, 2013 at 8:37pm

Chemistry
Ba(OH)2 is a strong electrolyte. Determine the concentration of each of the individual ions in a 0.700 M Ba(OH)2 solution. I know that Ba(OH)2 -> Ba + 2OH But how do I determine the concentrations? I feel like I am making this more complicated than need be
Monday, April 8, 2013 at 7:27pm

Chemistry
What is the pH of a 0.1 M NaOCl solution (Ka of HOCl is 2.95 x10-8) I did: x squared/.10= 2.95x10-8 x squared= 2.95x10-9 x= 5.43x10-5 -log(5.43x10-5)= 4.27 pH However, the options I'm given are either a.) 3.74 b.) 6.47 c.) 8.23 d.) 10.27 What steps am I doing wrong?
Monday, April 8, 2013 at 7:08pm

Chemistry
titration of a 50.00mL of KOH required 175.00mL of 0.0150M acetic acid, what is the Molarity of KOH solution
Monday, April 8, 2013 at 7:07pm

Pages: <<Prev | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | Next>>

Post a New Question | Current Questions

Homework Help: Science

For Further Reading