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Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

Chemistry
Calculate the thiocyanate concentration at equilibrium if the irone (III) ion concentration is 0.23 M and the complex ion concentration is 0.625 M t equilibrium. Keq= 138M^-1

chemistry
Could somebody tell me dose my answer for this question right or wrong for this question.My answer is reverse 2SO2(g) + O2(g) ↔ 2SO3(g) which has Kp = 3.45 x 106 at 600K. In an experiment, SO3 at pressure 125 atm is mixed with SO2 at pressure 0.13 atm and O2 at pressure 0....

Chemistry
A sample of sand initially at 22.3°C absorbs 1.34 x 10^3 J of heat. The final temperature of sand is 67.8 °C. What is the (in g) of sand in the sample? Round to the nearest whole number.

chemistry
The following information is given for ether, C2H5OC2H5, at 1atm: boiling point = 34.6 °C Hvap(34.6 °C) = 26.5 kJ/mol specific heat liquid = 2.32 J/g°C At a pressure of 1 atm,__kJ of heat are needed to vaporize a 25.1 g sample of liquid ether at its ...

chemistry
A fixed amount of oxygen gas is held in a .500 L tank at a pressure of 4.68 atm. The tank is connected to an empty 1.50 L tank by a tube with a valve. After this valve has been opened and the oxygen is allowed to flow freely between the two tanks at a constant temperature, ...

Chemistry
When .1625 g of Magnesium is burned in a bomb container that has a heat capacity of 3.03 kJ/ºC, the temperature increases by 1.252 ºC. How much heat (kJ/mol) is liberated during the burning of magnesium? Just want to make sure I am doing this correctly: q = ms∆T q = (....

Chemistry
Calculate the enthalpy of formation if 78.5 g of carbon dioxide in the following reaction: C(s) + H2O(g) --> CO2(g) Use the following equations: a) H2O(l) --> H2(g) + (1/2)O2(g): Δ°f = +285.8 kJ/mol b) C2H6(g) --> 2C(s) + 3H2(g): Δ°f = +84.7 kJ/mol c) 2CO2(g) + ...

Chemistry
In which of the following reactions is work done by the system to the surroundings? A) 2CH3OH(l) + 3O2(g) --> 4H2O(l) + 2CO2(g) B) S(s, rhombic) + O2(g) --> SO2(g) C) 2AgNO3(s) --> 2AgNO2(s) + O2(g) D)4Fe(s) + 3O2(g) --> 2Fe2O3(s) My guess is B because according to...

Chemistry
8) ( 1 point) What is the maximum number of grams PH₃ that can be formed when 3.4 g of phosphorus reacts with 4 grams of hydrogen to form PH₃? P₄ (g) +6H₂ (g) → 4PH₃ (g) * 3.7 g 6.8 g 45 g 270 g 10. Lead nitrate can be decomposed by heating. What is the percent ...

SCIENCE
WHAT IS MEAN OF CHEMISTRY?

Chemistry
A solution is prepared by pipetting 5.00 mL of 0.0983 molar HCl into a 100.0 mL graduated cylinder, and adding enough water to prepare 50.0 mL of solution. 1.The concentration of this solution is ____________M 2.The pH of this solution is ____________ Because HCl is a strong ...

chemISTRY
A hot lump of 33.2 g of copper at an initial temperature of 70.5 °C is placed in 50.0 mL of H2O initially at 25.0 °C and allowed to reach thermal equilibrium. What is the final temperature of the copper and water given that the specific heat of copper is 0.385 J/(g·°C)? ...

Chemistry
A 32.3 g iron rod, initially at 22.4 ∘C, is submerged into an unknown mass of water at 62.9 ∘C, in an insulated container. The final temperature of the mixture upon reaching thermal equilibrium is 59.4 ∘C.

Chemistry help!!
Calculate the concentration of a solution prepared by adding 15.00 mL of 2.10 X 10^-3 M KMnO4 from a buret into a 50.00 mL volumetric flask, which is then filled to the 50.00 mL graduation mark with distilled water.

Chemistry (Ochem)
I know that there is such thing as inversion of stereochemistry,but is there such thing as inversion of stereocenter? Are stereocenter and stereochemistry the same thing or mean the same thing? Thank you, Vivian

Chemistry
Which elements have the greatest tendency to behave as oxidizing agents? A) metals B) nonmetals I think the answer is B.

Chemistry
Write an equation for the half-reaction in which a potassium atom, K, is oxidized. A) K + e- ----> K+ B) K ----> K+ + e- C) K- ----> K+ + 2 e- I think A

Chemistry
Calculate the enthalpy of formation of carbon dioxide in the following reaction: C(s) + O2(g) -> CO2(g) Use the following equations: a) H2O(l) --> H2(g) + 1/2 O2(g): ΔH° = +285.8 kJ/mol b) C2H6(g) --> 2C(s) + 3H2(g): ΔH° = +84.7 kJ/mol c) 2CO2(g) + 3O2(g) --> ...

chemistry
calculate the heat of formation of methane given the heat of combustion of C,H2 and CH4 as-393,-285 and -887kj per mol respectively.

Chemistry
PbO2 + 2H2 = Pb + 2H2O If 478g of lead doixide is heated, what is: a. the number of moles of lead dioxide used? b. the number of moles of lead produced? c. the mass of lead produced? I am stuck.... please help!!

maths
3. Suppose a bookcase shelf has 5 Mathematics texts, 3 Biology texts, 6 Chemistry texts and 4 Physics texts. Find the number n of ways a student can choose: a. one of the texts; b. one of each type of text.

Chemistry
A store receives a shipment of defective balloons. Each has a tiny pinhole of the same size. If one balloon is filled with helium and another is filled with air to the same volume and pressure, which balloon will deflate faster and how much faster? The density of helium at ...

Chemistry
The molar mass of a compound is 92 g/mol. What is the molecular formula for a sample containing 0.606g Nitrogen and 1.390g Oxygen?

Chemistry
What is the limiting reactant is if 0.5gAl is reacted with 3.5gCuCl2? 2Al(s)+3CuCl2(aq) --> 3Cu(s)+2AlCl3(aq)

chemistry
what is the cell potential of the following cell: a platinum wire placed into a mixture of: KIO4 (0.02M), KIO3 (0.040M), H3PO4 (0.10M), KH2PO4 (0.40M) assuming it is put against a Ag/AgCl reference electrode?

chemistry
Calculate the molar mass of a gas if 4.40g occupies at 3.50 L at 560mmHg and 41 degrees celsisus

Chemistry
Refer to the table given for the ionic radii in your lab manual and approximate the attractive portion of the lattice energy for 1 mole of the following salts. (Consider only one bond if more than one bond exists.) a) Ca3P2 ___J b) MoCl4 ___J c) Cs2O ___J

Chemistry
what is the Mr of CO2? Use this to calculate the mass of co2 produced when 1kg of CaCO3 is heated.... (what are the answers?) MT!!!

Chemistry
Use the ion-electron method to write and balance the net ionic equation for each of the following reactions. MnO41- + Sn(OH)31- MnO2 + Sn(OH)62- in basic solution MnO41- + (COOH)2(aq) Mn2+ + CO2(g) in acidic solution I2(aq) + S2O32- I1- + S4O62- Zn(s) + HgO(s) ZnO(s) + Hg(l) ...

chemistry
60.0 g of iron that has an initial temperature of 250 degrees C and 60.0 g of gold that has an initial temperature of 45.0 degrees C are brought into contact with one another. Assuming no heat is lost to the surroundings, what will be the temperature when two metals reach ...

Chemistry
Determine the final temperature of water if 17.6 kJ of heat is added to 350 g of water initially at a temperature of 24.10 C. (specific heat of water is 4.184 Jg^-1K^-1)

chemistry
Calculate how many cm3 of 1M HCl is necessary to dissolve 1g of magnesium ribbon

chemistry
If you need to prepare 250.0 mL of a pH 5.00 buffer tha t has a total buffer concentration of acetic acid + sodium acetate of 0.050 M, how many moles of each will you need to prepare the solution? Given solutions of acetic acid and sodium acetate with concentrations of 0.10 M ...

Chemistry
carbon disulfide is prepared by heating sulfur and charcoal. the chemical equation is S2(g)+C(S)=CS2(g) and Kc = 9.4 at 900K. How many grams of CS2(g) can be prepared by heating 8.9moles of S2(g) with excess carbon in a 5.00L reaction vessel held at 900K until equilibrium is ...

Chemistry
I am having trouble getting the right answer for this question please help. Calculate Kc for the FeSCN2+ formation equilibrium [FeSCN2+] = 3.49x10^-5 M [Fe3+] = 4.39x10^-4 M [SCN-] = 1.93x10^-4 Kc = [FeSCN2+] / ([Fe3+]-[FeSCN2+]) * ([SCN-] - [FeSCN2+]) I keep getting 546.266 M...

chemistry
Suppose a balloon is filled so that its volume is 2.00 L when the pressure is 1.10 atm and the temperature is 300k. What volume will it occupy if it rises to an elevation where the pressure is 418mm Hg and the temperature is 200k?

Chemistry
A gas occupies 56.44 L at 2.00 atm and 310 K. If the gas is compressed to 23,520 mL and the temperature is lowered to 281 K, what is the new pressure in torr?

Chemistry
Of the compounds below,_____ has the smallest ionic separation and why? A.RbF B.K2S C.SrBr2 D.KF E.RbCl --> How does one determine if a compound has a high or low ionic separation, and what is ionic separation?

Chemistry
Of the compounds below,_____ has the smallest ionic separation and why? A.RbF B.K2S C.SrBr2 D.KF E.RbCl --> How does one determine if a compound has a high or low ionic separation, and what is ionic separation?

Chemistry
A 0.75 g sample of X2CO3 is dissolved in water and 80 mL of 0.20 M CaCl2 solution is added. This is the balanced equation I have created. X2CO3(aq) + CaCl2(aq) → CaCO3(s) + 2 XCl(aq) Based on the ratio in your balanced equation, how many moles of X2CO3 must have reacted? How...

chemistry
What equation is formed when HCl is titrated against Na2CO3 using methyl orange as indicator

Chemistry
A 1.50-g mixture of the solid salts Na2SO4(molar mass 142.04 g/mol) and Pb(NO3)2(molar mass 331.20 g/mol) forms an aqueous solution with the precipitation of PbSO4 molar mass 303.26 g mol The precipitate was filtered and dried, and its mass was determined to be 0.392 g.The ...

chemistry
20cm(cube) of a gaseous hydrocarbon were mixed with 90cm(cube) oxygen, and the mixture exploded. At room temperature, 60cm(cube) of gas were left. 40cm(cube) of the gas(cabon(4)oxide) were absorbed by sodium hydroxide, leaving 20cm(cube) of oxygen. find the empirical formular ...

chemistry
I need help. please show step by step? How many milliliters of 1.0 M NaOH would be required to completely neutralize 40.0 mL of 0.60 M HCl?

chemistry
6.10g of boron reacted completely with 22.9g of chlorine to give 29.0g of the metallic chloride. Calculate the empirical formula of the chloride.

Chemistry
A solution of boric acid (H3BO3) in water has a pH of 3.45. If the solution also contained NaHBO3, what do you expect to happen to the pH? Increase Decrease Stay the same Not enough information provided

Chemistry
A solution containing 10.50g aniline in 226g of benzene lowers the freezing point of benzene by 2.60°C. What is the molar mass of aniline? Thank you in advance

Chemistry
the freezing point of a water solution containing 26.1g of a non electrolyte in 538g of water is 0.73°C. what is the molar mass of the solute Thank you in advance

chemistry
A 5.309 g antacid tablet, with CaCO3 as the active ingredient, was mixed was 30.0 mL of 0.831 M HCl. After the reaction occurred, it took 15.3 mL of 0.7034 M NaOH to neutralize the excess acid. a) How much HCl (in mL) of was neutralized by NaOH? b) How much HCl (in mL) was ...

Chemistry
1.33dm³ of water at 70°c are saturated by 2.25moles of Pb(NO3)2, and 1.33dm³ of water at 18°c are saturated by 0.53mole of the same salt. If 4.50dm³ of the saturated solution are cooled from 70°c to 18°c.calculate the amount of solute that will be deposited in a). ...

Chemistry
Please help! I'm trying to find the solubility of Ca(OH)2 in .001305 mol/L aqueous NaOH? Saturated solution of Ca(OH)2 in 0.01305 mol/L NaOH. [HCl] = 0.1213 M Volume of HCl = 9.81 mL Volume of Ca(OH)2/NaOH aliquot = 25ml Find: 1. the TOTAL [OH-] in the saturated solution of Ca...

Chemistry
Calculate the wavelength, in nanometers, of the spectral line produced when an electron in a hydrogen atom undergoes the transition from the energy level n = 4 to the level n = 1.v

Chemistry
You need to make 40.00 ml of a 0.045M NaOH solution from a 2.1M stock solution. How many ml of the stock solution are needed?

Chemistry
A solution of a weak acid (.025M, 200ml) is mixed with a solution of NaOH ( 0.015M, 150ml). The equilibrium pH is 5.51. What is the Ka of the weak acid?

chemistry
What would the predicted voltage be if four Zn(s)/ Zn2+(aq) // Ag+(aq) / C (s) cells were connected in series

A.P Chemistry
For a certain reaction ∆H is 54 kJ/mol and ∆S is 128 J/mol · K. This reaction can become spontaneous only above some temperature. What is this temperature? Answer in units of ◦C.

Chemistry
How did the net voltage of the two cells connected in series compare to the net voltage of a single why the calculated cell potentials and the observed cell potentials might be different

chemistry
consider equilibrium equation below `Mg(NO3)2(aq) + 2Na(OH)(aq) <--> Mg(OH)2(s) + 2NaNO3 (aq) If NH3 is added, according to Le Chatelier's Principle, which way would reaction shift?

Reposting Chemistry Question -Emergency !!
Saturated solution of Ca(OH)2 in 0.05349 mol/L NaOH. Temperature: 22.1 * C Volume of Ca(OH)2/NaOH aliquot: 25ml Concentration of Standard HCl: 0.1213M Indicator Used: Bromothymol Blue Ksp from previous part I got 3.55x10^-5 - Average volume of HCl added to titrate was 15.05 mL...

Chemistry
How many moles of magnesium nitride form when 1.0 mole of magnesium reacts completely?

Chemistry
Determine the pH at the equivalence point when 25.00 mL of 0.1056 M CH3COOH is titrated with 0.1056 M NaOH.

Chemistry Explanation??
So what would the explanation for this be? Its really confusing me. The Ksp is independent of [NaOH] while the solubility of Ca(OH)2 decreases as the [NaOH] increases. Explain why this is the case. ( in the data table, the naoh concentration is 0 M, and the solubility is 2.30 ...

Chemistry
what is the oxidation number of Carbon in C6H12? thank you!

Chemistry 2202
Henry uses 0.150L of 0.500 mol/L NaOH to neutralize 250.0 mL of the hydrochloric acid. What is the concentration of the HCl (aq)?

Chemistry
An empty aerosol-spray can at room temperature (20 ◦C) is thrown into an incinerator where the temperature reaches 458◦C. If the gas inside the empty container was initially at a pressure of 1 atm, what pressure did it reach inside the incinerator? Assume the gas was at ...

chemistry
. What is the pH of a solution in which 15 mL of 0.10 M NaOH is added to 25 mL of 0.10 M HCl?

chemistry
calculate the mass at 15.0 L at NH3 at 27 digree Celsius and 900 mm hg?

physical chemistry
a mixture of toluene and water boils at 90 degrees. calculate the vapour pressure at this temperature. Assume the atmospheric pressure to be 760 mmHg

Chemistry
How many joules are required to raise the temperature of 450mL of water from 30 °C to 100 °C? The specific heat of copper metal is 0.385 J/ g- K. How many KJ of heat needed to raise the temperature of 1.1 kg block of copper from 27.5 C to 50 C? If 200 J of heats is added to...

chemistry
The specific heat of copper metal is 0.385 J/ g- K. How many KJ of heat needed to raise the temperature of 1.1 kg block of copper from 27.5 C to 50 C?

Chemistry
What mass of ammonia is necessary to produce 500 kJ of heat? 4 NH3(g) + 5 O2(g) → 4 NO(g) + 6 H2O(g) ΔrH = -906 kJ mol-1

Chemistry
The enthalpy of combustion of butane C4H10 is described by the reaction: C4H10(g) + (13/2) O2(g) -> 4CO2(g) + 5H2O(g) ΔH°rxn = –2613 kJ/mol Given the following enthalpies of formation: ΔH°f[CO2(g)] = -393.5 kJ/mol ΔH°f[H2O(g)] = -241.8 kJ/mol Calculate the value of ...

Chemistry
1)What is the pH of a 0.25 M solution of acetate (CH3COO-) with a pKa of 4.76? 2)If the [OH] of a solution is 2.95 x 10-5M, what is the pH of the solution? 3)Determine the pH at the equivalence point when 25.00 mL of 0.1056 M CH3COOH is titrated with 0.1056 M NaOH. 4)Determine...

Chemistry Titration-emergency :(
[HCl]=0.1213M Avg Amount HCl added: 14.15mL Volume of Saturated Solution of Ca(OH)2 in NaOH used: 25 mL and its concentration was 0.05349 M. 1.)Calculate the total [OH ] in the saturated solution of Ca(OH)2 in sodium hydroxide -> for this do I only find the mols of HCl? and...

Chemistry
c) Now make up 500 mL of a 0.025M phosphate buffer using the 0.1M phosphate buffer. Show all your workings. The 0.1M is made of 120.1ml conjugate base and 379.9ml acid.

Chemistry
c) Now make up 500 mL of a 0.025M phosphate buffer using the 0.1M phosphate buffer. Show all your workings. The 0.1M is made of 120.1ml conjugate base and 379.9ml acid.

chemistry
Under the same condition temperature and pressure hydrogen diffuses 8 times as fast as gas y calculate the rmm of gas y the rmm of h=2

Chemistry
Determine the final temperature of water if 17.6 kJ of heat is added to 350 g of water initially at a temperature of 24.10 C. (specific heat of water is 4.184 Jg^-1K^-1)

Chemistry
Calculate the tota bond energy of ethanol from this info:(C_C=347,C_H=414,H_O=464,C_O=360)kJ​mol-1.Thanks for responding

chemistry
according to the data in the merck index,if 1,0g of aspirin is dissolved in 100ml of water at 37,how much aspirin will precipitate out of solution when it is cooled to 25.

Chemistry
Given below is a reaction 2Mg+O2 = 2MgO Mass of magnesium oxide formed by buring 24g of magnesium in air is a.16g b.80g c.20g d.40g

chemistry
Calculate the pH of a buffer solution prepared by mixing equal volumes of 0.20 M NaHCO3 and 0.10 M Na2CO3. (Ka = 4.3 x10-7)

Chemistry
What is the final temperature when 180.0 mL water at 101.3 C is added to 93.1 mL of water at 65.5 C?

Chemistry
A gas expands its volume from 4.7 L to 8.9 L at constant temperature. Answer the following: a) If the gas expands against vacuum conditions, calculate the work (in joules) done by the gas. b) Calculate the work done (in joules) by the gas if it expands against a constant ...

Chemistry
Which equation would describe the following equilibrium constant? Kc = [Bi3+]2[S2-]3 ----- Bi2S3 (s) <-> 2Bi3+ (aq) + 3S2- (aq) Bi2S3 (s) + 6HCl (aq) <-> 2BiCl3 (aq) + 3H2S (aq) BiS (s) <-> Bi3+ (aq) + S2- (aq) Bi2S3 (s) <-> 3Bi2+ (aq) + 2S- (aq)

chemistry
when hcl reacts with mg, how many grams of magnesium are needed to produce 100 grams of hydrogen?

Chemistry
Determine the pH of a solution after 20.00 mL of 0.4963 M HI has been titrated with 12.64 mL of 0.5174 M NaOH.

Chemistry
Determine the number of moles of NaCl in the solution. Measured Mass of NaCl: 11.69g Measured Vol of Water: 100mL Molar Mass of NaCL: 58.44g/mol 11.69gNaCL/58.44g/mol = 0.20 mol NaCl Do I then to multiply my answer by 100ml? 0.20 x 100=20.00mol NaCl?

chemistry
Calculate the mass of benzoic acid required to prepare 100cm3 each of 0.1m,0.25m, and 0.5m solutions

Chemistry
Consider the titration of 20.00 mL of 0.1728 M Ascorbic acid (Ka = 7.9 x 10-5) with 0.4329 M NaOH. Match the following regions in the titration curve with the appropriate pH range. 1.Initial pH 2.Before equivalence point 3.At equivalence point 4.After equivalence point A. 8 - ...

Chemistry
Determine the pH of a solution after 20.00 mL of 0.4963 M HI has been titrated with 12.64 mL of 0.5174 M NaOH.

chemistry
When a base is introduced into this buffer, which of H2CO3 and HCO3− reacts with the base to maintain the pH of the solution? HCO3− H2CO3

Chemistry
you have a solution of 0.1 m KCN and a solution of 0.1 m of HF what is the buffer?

Chemistry
You dissolve 2.35 g of sodium carbonate (Na2CO3) in sufficient water to produce a final solution volume of 100.0 mL. Assuming all of the solid dissolves, calculate the solution pH.

Chemistry
When the equation below is balanced and all coefficients are in the lowest, whole number ratio, the coefficients are: Bi+O2⟶Bi2O3

organic chemistry
2. An unknown white solid has melting point range 119 – 121o C. Benzoic acid is a white solid of 122 o C melting point. How can a student confirm the identity of the unknown solid (is the benzoic acid or not)

chemISTRY
What is the rms speed of N2 molecules at 281 K? What is the rms speed of He atoms at 281 K? where R=8.314

CHEMISTRY
If He(g) has an average kinetic energy of 4190 J/mol under certain conditions, what is the root mean square speed of Cl2(g) molecules under the same conditions?

chemISTRY
Under identical conditions, separate samples of O2 and an unknown gas were allowed to effuse through identical membranes simultaneously. After a certain amount of time, it was found that 5.36 mL of O2 had passed through the membrane, but only 3.60 mL of of the unknown gas had ...

Chemistry help!!
Phosphoric acid, H3PO4, has some important applications. It can be used to produce fertilizers and it is present in soft drinks. Phosphoric acid can be made from phosphorus in a two step process: Reaction 1: P4 + 5 O2 --> P4O10 Reaction 2: P4H10 + 6H2O--> 4H3PO4 A ...

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