Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

Chemistry
A kettle contains 2kg of water at 20 degree celsius. What mass of methane must be burned to raise this quantity of water to 100 degree celsius?

chemistry
How many electrons are in the highest energy orbital of the element copper? There is 1 in the outermost shell but what about the highest energy orbital?

Chemistry
what salt results from the neutralization of phosphoric acid with potassium hydroxide? would it be: 3NaOH + H3PO4 -> Na3PO4 + 3H20 OR H3PO4 + sKOH -> K3PO4 + 3 H2O

Chemistry
what salt results from the neutralization of phosphoric acid with potassium hydroxide? would it be: 3NaOH + H3PO4 -> Na3PO4 + 3H20 OR H3PO4 + sKOH -> K3PO4 + 3 H2O

Quantitative Chemistry
Which of the following statements about the reaction, 4 HCl(aq) + MnO2(s) MnCl2(aq) + 2 H2O(l) + 2 Cl2(g), is correct? a.)The manganese atoms are oxidized. b.)The oxygen atoms are reduced. c.) The chlorine atoms are both oxidized and reduced. d.)All of these statements are ...

Chemistry
To neutralize 8.3 4 ml of HCl 36.5% by mass and density = 1, 2 g/cm3, the required volume of 5 mol/L NaOH will be?

Chemistry
Mercury(II) sulfide, HgS, is practically insoluble in pure water. Its solubility at 25 degrees C is probably no more than 3×10^−25 g/L. Of the following quantities of pure water, which is the smallest quantity that could be used to make a saturated solution of HgS?

Chemistry
Usinf your periodic table, Indicate whether each other following substances could act as an oxidizing agent (OA), a reducing agent (RA) or both (OA/RA): (A.) Ba2+ (aq) So I think it should be reduction because it gained 2 electrons? (B.) Co2+ (aq) : RA (C.) Se(s) : (D.) Cs(s...

Chemistry
Suppose the osmotic pressure of blood at 37 °C is 7.65 atm and you are preparing an intravenous (IV) NaCl solution for a patient. What concentration (in M) of NaCl solution should you prepare so the resulting IV solution is isotonic with blood, if the van’t Hoff factor of ...

Chemistry
If .0162 moles of sodium sulfide is dissolved in 100.0 mL of water, what is the concentration of sodium ions [Na⁺] in solution?

Chemistry
In a reaction vessel, 500. mL of 0.100 M Na3PO4(aq) is combined with 200. mL of 0.400 M Pb(NO3)2(aq). (a) Write the molecular equation for the reaction that occurs. Balance the equation using lowest whole numbers and be sure to include states. (b) Identify the limiting ...

chemistry
Balance this equation. If a coefficient of "1" is required, choose "blank" for that box. CH4 + O2 → CO2 + H2O

Chemistry
Consider the reaction: 2H2+2NO -> N2+2H2O. Initially 1.20mol of H2 and 0.95mol of NO are placed in a 2.50L container(all reactants and products are gases) if after 5seconds the amount of H2 has been reduced to 1.02mol. How much NO is left? And how much N2 and H2O has been ...

chemistry
On heating 25g of a saturated solution to dryness at 60oc, 4g of anhydrous salt was recovered. Calculate its solubility in grams per 100g of solvent

Chemistry
How can I do an acrostic poem for the word REDOX?

chemistry
Which conducts better, BeCl MgCl2

Chemistry
A current of 10 amps passes for an hour through a solution of sodium chloride with a volume of 1L by poles of pt,calculate the pH of the solution after the electrolysis is finished.

chemistry
Hi, I posted this question earlier.. 100 g of water, H2O, is heated from 25C to 50C. What is the entropy change for the process? Cp = 4.2J/K·mol for water? I was told 100*4.2ln(323 K/ 298k) was the way to calculate it, it does not produce the correct answer.. I also tried to ...

chemistry
the air in a 4.00L tank has pressure of 1.70atm what is the pressure in atmospheres 1L

chemistry
HF hydrolyzes according to the following equation: HF(aq)+H2O(l)<-> H3O+(aq)+F-(aq) When 0.0300 mol of HF dissolves in 1.0 L of water, the solution quickly ionizes to reach equilibrium. At equilibrium, the remaining [HF]=0.0270 M. a.) How many moles of HF ionize per ...

Chemistry
Suppose the osmotic pressure of blood at 37 °C is 7.65 atm and you are preparing an intravenous (IV) NaCl solution for a patient. What concentration (in M) of NaCl solution should you prepare so the resulting IV solution is isotonic with blood, if the van’t Hoff factor of ...

Chemistry
In a laboratory, the following reaction is performed by combining 358 g of H2O and a sufficient amount of CaC2. The percent yield for this reaction is 94.5%. Calculate the actual yield of acetylene (C2H2) in grams from this reaction. CaC2 + 2H2O C2H2 + Ca(OH)2

Chemistry
How many mL of a 0.5M Ca(OH)2 solution are needed to neutralize 38 mL of a 2M HNO3 solution? ANSWER IS: x = multiply / = divide 38mL HNO3 X 1 L HNO3 x 2M HNO3 x 1 L Ca(OH)2 x 2M Ca(OH)2 x 1000 mL / 1000 mL/1L HNO3/..5mL Ca(OH)2/1M HNO3/1L = 304 mL Ca(OH)2

Chemistry
Describe the procedure you would follow to determine the concentration of Vitamin C in a sample if the volume of DCPIP required to reach the endpoint was more than the 25-mL flask could hold. Note the titration must still be carried out in the flask. Be sure to include any ...

Chemistry- polarity
Is 2,4-Hexadiyne-1,6-diol a polar or non-polar compound? I think it is non-polar, based on the the high retention factor (0.89) I got from the TLC.

chemistry
Calculate no: of moles of cl2 produced at equilibrium when 1 mole of pcl5 is heated in 10 DM vessel kc 0.041

chemistry
14. 100 g of water, H2O, is heated from 25C to 50C. What is the entropy change for the process? Cp = 4.2J/K·mol for water?

Chemistry
Describe the procedure you would follow to determine the concentration of Vitamin C in a sample if the volume of DCPIP required to reach the endpoint was more than the 25-mL flask could hold. Note the titration must still be carried out in the flask. Be sure to include any ...

chemistry
What is the concentration of IO3- (total volume: 20mL) when you have .00001mol of HSO3- (total volume: 10mL)? Use the balanced equation IO3-(aq)+3HSO3-(aq)>>>I-(aq)+3S​O4^2-(aq)+3H+(aq)

chemistry
How to find the moles of IO3- reacted when you have .00001mol of 10mL HSO3-? Using the equation IO3-(aq)+3HSO3-(aq)>>>I-(aq)+3S​O4^2-(aq)+3H-(aq)

Chemistry
What are the number of molecules in 16g of h2co3??

Chemistry
If i have 0.5 mole of hydrogen peroxide how many moles of oxygen would be produced assuming all of the hydrogen peroxide decomposes?

Chemistry
A solution contains 14% by mass of h2so4.find the number of moles of h2so4 in 155g of solution

Chemistry
Most fish need at least 4.00 ppm dissolved O2 for survival. (a) What is this concentration in M (assume the density of the solution is 1.00 g/mL)? (b) What partial pressure of O2 above the water is needed to obtain this concentration at 10. °C? The Henry’s law constant for ...

chemistry
how do i figure out grams/tablet if I am in units of mol/L? >_>

Chemistry
If i have 0.5 mole of hydrogen peroxide how many moles of oxygen would be produced assuming all of the hydrogen peroxide decomposes?

chemistry
How can i be accurate when assigning oxidation numbers? By this i refer to elements that have more than 1 oxidation # . For example: I have been working with hydrides and i had this reaction in mind: Nb + H Shoud i use 3 or 5 for Nb, why?

Chemistry
Classify the following as pi-donating, pi-accepting, or pi-non-bonding. NH3,H2O,H2S

chemistry
How many mL of 0.4040 M HNO3 would be needed to neutralize 55.00 mL of 0.1234 M potassium hydroxide?

Chemistry
I need help with this systhesis problem 1-propyne ----> 1.) 1 equivalent of NaNH2 2.)CH3CH2Br 3.) H2 Lindlar Catalyst 4.) HCl 5.)NaN3

Chemistry
Rubbing alcohol often contains propanol, C3H7OH. Suppose you have an 85.9 g sample. a) How many carbon atoms are in the sample? b) How many hydrogen atoms are in the sample? c) How many oxygen atoms are in the sample? For a, I have tried dividing 85.9 by the total mass, 60....

chemistry
How many grams of cuso4.5h2o are require to prepare 100ml of 500ppm cu

Chemistry
1. Before the Industrial Revolution, the concentration of CO2 in Earth’s atmosphere was about 275 ppm. Considering the effect of CO2 only, calculate the effect that the increase in CO2 has had on the pH of precipitation

chemistry
For the oxidation- reduction reaction equation given here, 2Na+S -> Na2S indicate how many electrons are transferred in the formation of one formula unit of produce.

Chemistry
What is mass in grams of a pure iron cube that has a volume of 4.10 cm3

Chemistry
Consider the reaction: K2S(aq)+Co(NO3)2(aq)=2KNO3(aq)+CoS(s) what volume of 0.255 M K2S solution is required to completely react with 160 mL of 0.130 M Co(NO3)2?

Chemistry
How many grams of a stock solution that is 85.5 percent H2SO4 by mass would be needed to make 150 grams of a 45.0 percent by mass solution? Show all of the work needed to solve this problem.

Science - Chemistry
1. Dalton's idea that atoms cannot be divided into smaller parts was disproved by the discovery of the ____. 2. The description of the structure of the atom is called the ___. 3. In a water molecule, two atoms of hydrogen and one atom of oxygen share electrons. A _____ bond is...

Chemistry
How many electrons does the bromine of BrF3 have in its outermost valence shell? Is it still seven like it would be when Br is by itself? Is it four because the three F would "take" one each to fill their octets? Or is it some other number?

Chemistry
I got pH = 5.3 A 1.00 L buffer solution is 0.250 M in HC2H3O2 and 0.250 M in NaC2H3O2. Calculate the pH of the solution after the addition of 0.150 mol of solid NaOH. Assume no volume change upon the Additon o f NaOH. The Ka value for HC2H3O2 at 25 C is 1.8 x 10^-5. Chemistry-...

Chemistry-Dr.Bob222
A 1.00 L buffer solution is 0.250 M in HC2H3O2 and 0.250 M in NaC2H3O2. Calculate the pH of the solution after the addition of 0.150 mol of solid NaOH. Assume no volume change upon the Additon o f NaOH. The Ka value for HC2H3O2 at 25 C is 1.8 x 10^-5.

Chemistry
A 6.5 g of zinc powder reacts completely with access HCL and 1.5 L of H2 are obtained find max volume of H2

Chemistry
Consider the generic reaction between reactants A and B: 3A+4B→2C How many moles of B will be in the reaction vessel once the reactants have reacted as much as possible? (Assume 100% actual yield.)

Chemistry
One more, confused How can you tell by the periodic chart which ions of metals are most easily reduced or oxidized. A website or video would be fine. I know it is quite involved. thanks again

chemistry
Dr Bob Could you check this please? Voltaic cell---cathode is positive, accepts electrons, reduced, anode is negative, gives up electrons and is oxidized Electrolytic cell------cathode is negative, accepts electrons and is reduced. Anode is positive, givesup electrons and is ...

Math
Ann earned $30 babysitting and $15 painting a fence.How do her earnings compare with the cost of a $70 chemistry set?

Chemistry
What is the solubility of ZnCO3 at 25 o C in a buffer solution with a pH of 9.74?

Chemistry
If 125 grams of KClO3 decomposes completely, how many moles of oxygen gas is produced?

chemistry- gaz and stoechiometry
We have to prepare 500 gr of a HCl solution 15% by mass: H2SO4 + NaCl at a Temperature of 100°C NAHSO4 is also produced The equation is: H2SO4 + NaCl->NaHSO4 + HCl 1) How many grams of H2SO4 93% by mass and of NaCl do we need if we consider a loss of 3,O% of HCl during the...

chemistry
Determine the concentration of 20.0 mL of the sulphuric acid when 1.00 mol/L sodium hydroxide is used as the titrant. Observations: Initial volume of H2SO4 __________. Final volume of H2SO4 __________. Volume of H2SO4 added __________.

chemistry
what about a mixture whose specific rotation was found to be -9.2 degree?

Chemistry
Electrochemisry. Candy Chemist wishes to determine the concentration of CrO4^2- by electrochemical means in solution, and subsequently the Ksp of Ag2CrO4. She sets up one half-cell comprised of the Ag+|Ag couple (E=+0.799V) and a second half-cell in which a silver elctrode is ...

chemistry---
What is the equilibrium constant for the redox reaction in question 3? Combining the two equations for ∆Go below ∆G= −n F Ecell and ∆G= −R T ln K gives −n F E cell = −R T ln K... The ecell from question three was .73V The delta g from ...

chemistry
The fuel cell of h2 + o2 --> 2h2o has a cell potential of 1.23 V... If The equation for Ecell = Cathode - Anode, why wouldn't the cell be -.43 because anode = oxidation and cathode = reduction, right?

Chemistry
use the appropriate standard reduction potentials in the appendix of your book to determine the equilibrium constant at 285 K for the following reaction under acidic conditions 4H+(aq) + MnO2(s)+2Fe+2(aq)----> Mn+2 (aq)+2Fe3+(aq)+2H2O(l) The reductions potentials are 1.23 V...

Chemistry- gaz and stoechiometry
The preparation of KClO3 follows these equations: 2KMnO4 + 16HCl->2KCl + 2MnCl2 + 5Cl2 (g) + 8H2O 3Cl2 (g) + 6KOH ->KClO3 + 5KCl + 3H2O 1) How many moles of KClO3 are produced by one mole of KMnO4 I think the only link between the two equations is Cl2 but I don't ...

Chemistry
Aballon containing 546cm of air is heated at 10C if the presure is contain wht will be the volume at 20c

chemistry
The fuel cell of h2 + o2 --> 2h2o has a cell potential of 1.23 V... If The equation for Ecell = Cathode - Anode, why wouldn't the cell be -.43 because anode = oxidation and cathode = reduction, right?

Chemistry
Calculate the standard free-energy change for the following reaction at 25 °C. Standard reduction potentials can be found here. 2Au^3+(aq) + 3Cr(s) <-----> 2Au(s) + 3Cr^2-(aq)

Chemistry
Red mercury (II) oxide decomposes to form mercury metal and oxygen gas according to the following equation: 2HgO (s) yields 2Hg (l) + O2 (g). If 4.00 moles of HgO decompose to form 1.50 moles of O2 and 603 g of Hg, what is the percent yield of this reaction?

help !! chemistry
H2O(g) + Cl2(g) 2 HCl(g) + ½ O2(g) Heat of Reaction is WebAssign will check your answer for the correct number of significant figures. kJ Changed: Your submitted answer was incorrect. Your current answer has not been submitted. Information: COCl2(g) + H2O(g) CH2Cl2(l) + O2(g...

Chemistry
You are investigating the effect of strong base on the solubility of zinc hydroxide, Zn(OH)2 (s). (Ksp= 3 x 10- 15 for Zn(OH)2 (s)) You prepare 1.0 L solution of 0.10M NaOH and add excess zinc hydroxide, Zn(OH)2 (s). Instead of suppresing the solubility, you observe extra ...

Chemistry
The molar solubility of magnesium chloride in water is 0.23 M. What is the numerical value for Ksp for MgCl2? Suppose you wanted to reduce the concentration of dissolved Mg2+ to 0.00537 M by adding NaCl. What concentration of NaCl would you need?

Chemistry
Consider the titration of a 50.0 mL 0.500 M F- with 0.500 M HCl. The pKa of HF = 3.46 and the pKb of F- is 10.54. Calculate the pH at the following volumes of HCl added. 1. Vsa= 0.00 mL of 0.500 M HCl 2. Vsa= 25.0 mL of 0.500 M HCl 3. Vsa= 49.5 mL of 0.500 M HCl 4. Vsa= 50.0 ...

chemistry
A student designs an ammeter (a device that measures electrical current) that is based on the electrolysis of water into hydrogen and oxygen gases. When electrical current of unknown magnitude is run through the device for 1.00 min , 15.4 mL of water-saturated H2(g) is ...

Chemistry
Methyl amine is a weak base with a pKb=3.35. Consider the titration of 30.0mL of .030M of Methyl amine with 0.025M HCl. a) Write the appropriate equation for the reaction. b) Calculate K for the reaction in part (a). c) Calculate pH of the initial methyl amine solution (0mL ...

Chemistry
A gas occupies a volume of 4.64 x 102 mL at 519.57 mm Hg pressure. What will be its volume, at constant temperature, if the pressure is changed to 764.71 mm Hg?

Chemistry
A sample of sulfur hexafluoride gas (SF6) occupies a volume of 3.230 Liters at 7.011 x 101 oC. Assuming the pressure is constant, what will the final temperature be (in o C) if the volume is increased to 7.350 Liters?

Chemistry
Determine the mass, in grams, of water contained in 0.25 litres of aqueous solution that has 10% dissolved salt and density equal to 1.10 g/cm3

Chemistry-Dr.Bob222
Calculate the molar solubility of calcium hydroxide in a solution buffered at each pH. a. pH=4 b. pH= 7 c. pH=9

Chemistry-Dr.Bob222
Consider the compounds with the generic formula listed and their corresponding molar solubilities in pure water. Which compound has the smallest value of Ksp? a. AC; molar solubility = 1.35 x 10^-4 M b. AX2; molar solubility = 2.25 x 10^-4 M c. A2X; molar solubility= 1.75 x 10...

Chemistry
3. Which aqueous solution would you expect to have the lowest freezing point? 0.10 molal glucose, C6H12O6 or 0.10 molal NaCl solution

Chemistry
What is the osmolality of 1.1% NaCl salt solution? How can I calculate this?

Chemistry
How many grams of ethanol, C2H5OH, are required to make a 7.1M solution using 1.50 L of water

chemistry
how do i get pure samples from a mixture of potassium carbonate,ammonuim chloride and copper (ii)oxide

chemistry
explain how you can obtain pure samples from a mixture containing ammonium chloride,copper(ii)oxide and potassium carbonate

chemistry
explain how you can obtain pure samples from a mixture containing ammonium chloride,copper(ii)oxide and potassium carbonate

chemistry
Thanks for your help. I have a problem to solve et don't know how to do part of it. We have a solution of XNO3 (X = monovalent cation We add a solution of K2SO4. We obtain an insoluble sulfate which precipitate and KNO3 The precipitate = 3.900 g The analyses shows that the ...

Chemistry
What are the concentrations of acetic acid (pKa = 4.76) and acetate in a buffer solution of 0.15 M at pH 4.5? Please help me do this problem. I have no idea how to do it.

chemistry
An unkown vol of 2Mol of NaOH reacted with 3g of ethanoic acid .....get the volume of NaOH

Chemistry
Which of the following will be more soluble in an acidic solution than in pure water? Ag2SO4 CuI RbClO4 AlPO4 Cd(OH)2 Is the answer the first and second?

Chemistry
What volume of coffee (pH=5.0) would be required to have .25 moles of H3O+ ions? (must be two steps)

Chemistry
In the production of carbon disulfide (CS2), carbon (C) and sulfur dioxide (SO2) are reacted. If 8.00 g of sulfur dioxide reacts, how many moles of carbon dioxide are produced?

Chemistry
I need help please. The question is vinegar, or a dilute of CH3COOH (acetic acid), should have a molarity of around 0.83 M. Using the Ka for acetic acid, what should the pH of vinegar be?? Thank you!!

chemistry
Suppose the ÄGof, ÄHof, and ÄSo are available and valid at 298 K. Which equation(s) could be used to calculate the change in Gibbs Energy if all product and reactant concentrations (pressures) are 1 M (1 atm) and the temperature is 298 K? Choose all that apply. ÄG=ÄGo+RT ...

chemistry
Suppose the ÄGof, ÄHof, and ÄSo are available and valid at 298 K. Which equation(s) could be used to calculate the change in Gibbs Energy if all product and reactant concentrations (pressures) are 1 M (1 atm) and the temperature is 298 K? Choose all that apply.

Chemistry
Solution of formic acid (HCOOH) with a pH of 1.98. Find the molarity of the acid.

chemistry
How much heat must be removed from 75.0 grams of water at 90.0 degrees Celsius to cool it to 23.0 degrees celsius?

chemistry
If the water in 500mL of 0.44M NaCl solution is evaporated, what mass of NaCl will remain?

Chemistry
How many grams of MgCl2 would be required to make 440 g of magnesium ?

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Homework Help: Science