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Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

Chemistry
How does changing the volume of strontium nitrate solution, added to 8 cm3 of sodium carbonate solution, affect the amount of precipitate formed? Is it the more the strontium nitrate solution is increased, the more precipate formed?

chemistry
who prepaire tris buffer 0.2 mmol/lit calculation

chemistry
Write the equilibrium constant expression for the reaction 2 NO (g) + Br2 (g) ↔ 2 NOBr (g)

chemistry
Calculate the minimum volume oxygen gas that is required for the complete combustion of a mixture of 20cm carbon monoxide and hydrogen gas

Chemistry
Titration of 12.50 mL of HCl solution requires 22.50 mL of 0.1250 M NaOH solution. What is the molarity of the HCl solution?

chemistry
How many joules of heat are removed to completely covert 80.0 grams of water to ice at zero Celcius? For water: c = 4.179 J/g °C Hfusion = 333.528J/g Hvap = 2258.601 J/g

chemistry
How many joules of heat are required to completely covert 85.0 grams of water at 40.0° C to steam at 100°C? For water: c = 4.179 J/g °C Hfusion = 6.01 kJ/mol Hvap = 40.7 kJ/mol

Chemistry
Like a equilibrium constants, the values of Kw depends on temperature. At body temperature (37 C), Kw= 2.4 x 10^-14. What are the [H3O+] and pH of pure water at body temperature?

Chemistry
The equation for fermentation of glucose to alcohol and carbon dioxide is C6H12O6= 2C2H5OH + 2CO2 The enthalpy for the reaction is -67kj. Is the reaction endothermic or exothermic? Is the heat energy absorbed or released as the reaction occurs? I think its endothermic but im ...

Advanced Chemistry
he vapor pressures of several solutions of water-propanol(Ch3Ch2Ch2OH) were determined at various compositions, with thefollowing data collected at 45C: XH2O Vapor pressure (torr) 0 74.0 .15 77.3 .37 80.2 .54 81.6 .69 80.6 .83 78.2 1.00 71.9 a.) Are solutions of water and ...

chemistry
What is the main factor driving the difference in the spontaneity of the three reactions Cl^2,Br^2, and l^2?

Chemistry
Calculate the total amount of heat that must be added to convert 15.7g of ice at its melting point to steam at 100.0°C

Chemistry- Dr.Bob222
Determine [H30+], [OH-], and pH. A solution that is 0.655% HNO3 by mass (assume a density of 1.01 g/ mL for the solution).

Chemistry-Dr.Bob222
Like a equilibrium constants, the values of Kw depends on temperature. At body temperature (37 C), Kw= 2.4 x 10^-14. What are the [H3O+] and pH of pure water at body temperature?

math log rules / chemistry
hey so i have this equation i need to manipulate to solve for F- concentration. E1 = constant - 0.05916log[F] E2 = constant -0.05916log([F]+[Spiked]) E2-E1=-0.05916log(F+S) + 0.05916log[F] E2-E1/0.05916) = log[F+S] + log[F] how do I solve for log[F] ???

Chemistry
We did an experiment where we had to figure out the amount of water molecules in CuSO4xH2O (x being the value to find). If the stirring rod used was wet and was used to stir the beaker would this result in a higher x value? Is this a experimental or human error. Obviously this...

Chemistry
Assuming the solution you used was 95% ethanol by volume and that the density of ethanol is 0.816g/mL, how much water and carbon dioxide are produced in the experiment? Equation: C2H6O+3O2-->2CO2+3H2O (You start off with 2.0 mL of ethanol)

Chemistry
Given the amount of limiting regeant that you started with, how many moles of solid product did you expect to produce? Started with 1.12g of iron LR - iron Equation is 2Fe + CuSo4 -> Fe2So4 + Cu

Chemistry
A gas is trapped in a balloon. The gas chambee is 1.0 atm, the volume is 0.066 L, and the temperature is 298 K. When the temperature is changed to 308 K and the pressure remains constant, what is the new volume of the balloon?

Chemistry
if the pressure on a 1.00 L sample of gas is increased from 760. mm Hg to 2.00 atm at constant temperature what will the volume of the gas sample

physics, english, chemistry, maths
A girl whose mass 404g walk up a flight of 20steps each 150mm height in 10s find the average power developed Hint g = 10m/S

Chemistry-Dr.Bob222
A 25.0 mL sample of 0.125 M pyridine is titrated with 0.100 M HCl. Calculate the pH at 0 mL of added acid.

Chemistry
The pH of human blood needs to be between 7.35 and 7.45. You want to prepare a buffer solution that gives a pH of 7.40. You decide to use a sodium phosphate buffer: the acid is H2PO−4 and the conjugate base is HPO2− 4. You want the concentration of the acid to be 0...

Chemistry
To completely react 17g of barium hydroxide, how many grams of hydrochloric acid is needed?

Chemistry
Assuming the solution you used was 95% ethanol by volume and that the density of ethanol is 0.816g/mL, how much water and carbon dioxide are produced in the experiment? Equation: C2H6O+3O2-->2CO2+3H2O

Chemistry
Two electron configuration: Mg(Ne)3s^2 Zn(Ar)4s^2 3d^10 Using the configurations, explain the difference in relative reactivity of the 2 metals ( which are Mg and Zn)

Chemistry
Estimate the value of the equilibrium constant at 500 K for each of the following reactions. 2H2S(g)⇌2H2(g)+S2(g) I have calculate my delta H which is 168.9 kj/mol but I don't know where to go from there

pre-ap chemistry
how to make 100 mL of a 0.500 M CuSO4 solution

Chemistry
Will 1 L of 1 M NaCl contain more chloride ions than .5L of 1M MgCl2? Explain.

Chemistry
If a tire can hold 19L of air at 175 kPa and 25° C, what volume of air can the tire hold at 215 kPa and 30° C? Possible answers: A. 13.7 L B. 15.7L C. 23.0L D. 19L

Chemistry
Two electron configuration: Mg(Ne)3s^2 Zn(Ar)4s^2 3d^10 Using the configurations, explain the difference in relative reactivity of the 2 metals ( which are Mg and Zn)

Chemistry
The ions Cr3+ and O2- combine to form the ionic chromium oxide. in what proportions do these ions combine to produce a neutral compound?

Chemistry
Which pair of compounds will form a solution?Benzene (C6H6) and hexane (C6H14)Na2SO4 and benzene (C6H6)NaCl and hexane (C6H14)H2O and CCl4More than one of the combinations above will form solutions.

Chemistry
Name two solutions that can be used to precipitate out the following: PbCl2 Would I just use a random soluble compound and write a total ionic equation

Chemistry
What mass of sodium phosphate is needed to produce 75.00 g of solid product?

Chemistry
Two electron configuration: Mg(Ne)3s^2 Zn(Ar)4s^2 3d^10 Using the configurations, explain the difference in relative reactivity of the 2 metals ( which are Mg and Zn)

chemistry
Calculate the standard entropy change for the reaction of calcium oxide with water to form calcium hydroxide: CaO(s) + H2O(ℓ) → Ca(OH)2(s) at 298 K. ∆S ◦ m ∆H◦ f J K·mol? kJ mol? CaO(s) 39.75 −635.09 H2O(ℓ) 69.91 −285.83 ...

Chemistry
Balance the reaction step-wise: As2S3(s) + NO3^- + H^+(aq) to AsO4(aq) + S(s) + NO(g) + H2O(l)

Chemistry
If a half life of a radioactive element is twelve years,find the decay constant

Chemistry
In a student's experiment, when 40 mL of 6% (w/w) hydrogen peroxide solution was reacted with 10 mL 0.5 M FeCl3 solution, a ΔrH of -3,382 J was calculated. Calculate ΔH for this reaction in kJ mol-1. Give your answer to 2 decimal places, do not include the units in ...

Chemistry
Use the collision theory to explain the increase in rates of the other reactions

Chemistry - Oxidation-Reduction reactions
how would your calculation of the molarity of KMnO4 be affected if you had added twice as much sulfuric acid and water as was called for in the procedure?

Chemistry
t takes 572 kJ of energy to decompose 2.00 mol of liquid water. How much energy does it take to decompose 54.0 mol of water? 2H2O(l)+572kJ→2H2(g)+O2(g)

Chemistry
The estimated proven world oil reserves in 2013 were 1526 billion barrels. The world annual rate of use was 32.6 billion barrels. How long will these reserves last if this rate of use continues? (The rate of use is actually likely to increase.)

Chemistry
Burning 2.00 mol of hydrogen releases 483.6 kJ of energy. Determine how much energy, in kilojoules, must be supplied to convert 5.00 mol of water vapor into hydrogen gas and oxygen gas.

chemistry
Determine delta G naught at 298.15K for a 0.50 V voltaic cell if n=3 for that cell.

Chemistry
What is the molar solubility of Mg(OH)2 in a solution containing 0,10 M NH3 ? Ksp Mg(OH)2 = 1.2x10^-11 Kp NH3 = 1.8x10^-5

Chemistry
What is the molar solubility of Mg(OH)2 in a solução containing 0,10 M NH3 ? Ksp Mg(OH)2 = 1.2x10^-11 Kp NH3 = 1.8x10^-5

Chemistry
The molar solubility of a generic substance, Mg(OH)2 ksp = (1.2x10^-11) in 0.10 M NH3 Kb = 1.8 x 10^-5 help me please =)

Chemistry
A 50 g piece metal is placed in 250 g of methanol at 0 °C. The methanol is warmed to a temperature of 5 °C. What is the specific heat of the metal?

Chemistry
Could someone please help guide me through this question: A 1.047 g sample of He(g) is found to occupy a volume of 8.446 L when collected over hexane at 25.0 ∘C and 739.6 mmHg barometric pressure. Use these data to determine the vapor pressure of hexane at 25 ∘C.

Chemistry
Calculate the boiling temperature of a 0.50 M solution of sucrose. Assume that the concentration is 0.50 m.

Chemistry
Write balanced reaction for the following metal acid reaction A) Mg and HCI B) Zn and HCI

AP Chemistry
Consider the following reaction: PbCl2 + 2 NaOH → Pb(OH)2 + 2 NaCl What would be the major species observed floating in solution after one mole of PbCl2 and 2 moles of NaOH are mixed in aqueous solution? 1. Na+ ions, Cl− ions and H+ ions 2. Pb2+ ions, Cl− ...

chemistry
0.717g of potassium dihydrogen phosphate in 500ml concentration in ppm

chemistry
Consider the equilibrium reaction CO(g)+H2O(g)⇋CO2(g)+H2(g) Determine how each change in the left-hand column will stress the system and in which direction the equilibrium reaction will shift in response.

chemistry
commercially available concentrated hydrochloric acid is 37.0% w/w HCl. Its density is 1.18 g/mL. Using this information calculate (a) the molarity of concentrated HCl, and (b) the mass and volume (in mL) of solution containing 0.315 moles of HCl.

Chemistry
How much sweat (in mL) would you have to evaporate per hour to remove the same amount of heat a 120 W light bulb produces? (1W=1J/s.)

Chemistry
0.4276-g sample of a potassium hydroxide – lithium hydroxide mixture requires 31.20 mL of 0.3315 M HCl for its titration to the equivalence point. What is the mass percent lithium hydroxide in this mixture? 1.) 0.03120 L x 0.3315= 0.010343 moles HCl I'm not sure where I go ...

Chemistry
How+much+zinc+%28density+7.14+g%2Fcm3%29​+is+required+to+produce+13+grams+of+zinc​+chloride

chemistry
Aqueous sodium sulfate reacts with aqueous barium chloride to produce solid barium sulfate and aqueous sodium chloride. the solution contains 3.44g of barium chloride. you have a 0.282M solution of sodium sulfate. determine the volume of the sodium sulfate solution necessary ...

Chemistry
For the reaction 2 NO (g) + Cl2 (g) → 2 NOCl (g) If the concentration of NO is tripled, the rate of the reaction increases by a factor of nine. If the concentration of Cl2 is cut in half, the rate of the reaction is decreased to half the original rate. Find the order of ...

Chemistry 101
Write the molecular, total ionic, and net ionic, for the reaction. 1). Aqueous sodium carbonate is reacted with aqueous nickle (11) chloride. 2). Aqueous potassium hydroxide is mixed with aqueous hydrochloric acid.

Chemistry
[2.0 mol (-285.91 kJ/mol)] + [1.0 mole (0 kJ/mol)] - [1.0 mole (50.61 kJ/mol)] = ??? I came up with the answer of -622.43 but im not sure what the correct amount of significant figures would be and why? would 0 kj/mol be considered significant making the answer -600? what ...

Chemistry
Does either E1 and E2 involve a retention or inversion of stereochemistry? What happens to the stereochemistry in these reactions? I know stereospecificity is important for the reaction to occur, but I don't know what these means for the stereochemistry after the reaction ...

chemistry
what volume of glycerine C3H8O3, with a density of 1.26 g/mL should be taken to obtain 2.50 ml of glycerine?

Chemistry
A 110g piece of copper is heated and the temperature changes from 38C to 172C. The heat absorbed is 686 cal. What is the specific heat of copper. I think the answer is .385, but I have tried 100 different ways to get this answer or anything close, and I am lost..it is just a ...

chemistry
What is the equilibrium constant for 2A + 3B (double arrow) =4C Is it (C)^c/ (A)^a (B)^b

chemistry
Calculate the energy needed to produce 10 moles of Cl2O7 using this balanced equation. 2Cl +70+ 100kCal==2ClO7 please explain steps if I needed to calculate for 7 moles, how would it change?

chemistry
what is the concentration of 24.5g of Ca(NO3)2 in 244mL of water

Chemistry
Calculate the pH of the buffer formed by mixing equal volumes [C_2H_5NH_2]= 1.68 M with [HClO_4]= 0.966 M . Kb=4.3×10−4.

Chemistry
H2S+Is >2HI+S

Chemistry
What is the product for the following reaction: The reaction is a chair conformer of 1-methyl-1-cyclohexanol, with OH in the axial position and the methyl in the equatorial position, reacting with HCl. I'm wondering if this reaction is both SN1 and E1, and what are the E1 ...

Chemistry- Dr.Bob
A 40.0 mL sample of 0.100 M HNO2 is titrated with 0.200 M KOH. Calculate the pH at the equivalence point for the titration of HNO2 and KOH. When I did this problem again, I got pH= 8.08. Is this close to your answer? Dr.Bob: I estimated the pH and didn't come close to 11 or 12...

Chemistry
A 40.0 mL sample of 0.100 M HNO2 is titrated with 0.200 M KOH. Calculate the pH at the equivalence point for the titration of HNO2 and KOH. I got pH= 11.74.

Chemistry: Buffer Intensity problem
You wish to prepare a pH 4.76 acetic acid sodium acetate buffer with a buffer intensity of 1 M per pH. What concentrations of acetic acid and sodium acetate are needed?

chemistry
Air bags in cars are inflated by the sudden decomposition of sodium azide (NaN3) by the following reaction. 2 NaN3(s) −→ 3 N2(g) + 2 Na(s) What volume of N2 gas, measured at 1.31 atm and 85.0◦C, would be produced by the reaction of 65.0 g of NaN3? Answer in ...

chemistry
What volume of chlorine gas at 34.0◦C and 1.38 atm is needed to react completely with 9.40 g of sodium to form NaCl? Answer in units of L.

Chemistry
Which is more soluble in water, Cl2 or I2?

chemistry
how do i figure out the dilutions of 1.5L of a 15.0% (v/v) NaCl/water solution, what would the concentration of NaCl be if you added 3.0L of water

Chemistry
I'm not sure how to do these...I keep getting the wrong answers... Please help someone... Mg(s) + 2 HCl(aq)= MgCl2 (aq) + H2(g) a. What volume of 15.7 M hydrochloric acid will react with 2.1 grams of Mg? b. What mass of magnesium will react with 8.5 liters of 0.7 M ...

Chemistry
Calculate the mass of NaCl required to cause dissolution of 0.010 moles of AgCl in 100 mL of solution. Consider that the addition of NaCl does not cause increased volume in the solution KSP (AgCl) = 1.0 x 10 ^ -10 KF (AgCl2) = 3.0 x 10 ^ 5 Answer This Question

Chemistry
Calculate the mass of NaCl required to cause dissolution of 0.010 moles of AgCl in 100 mL of solution. Consider that the addition of NaCl does not cause increased volume in the solution KSP (AgCl) = 1.0 x 10 ^ -10 KF (AgCl2) = 3.0 x 10 ^ 5

chemistry
1.20 L of a solution that is 15.0 % of Pb(NO3)2 by mass (the density of the solution is 1.16 g/mL), starting with solid solute. how would you prepare this?

chemistry
A solution with a pH of 2.0 has a hydronium ion concentration ten times greater than a solution with a pH of?

Chemistry
If it is known that the iron(ii) salt is FeSO4.7H20 calculate the %Fe from the formula

chemistry
0.4276-g sample of a potassium hydroxide – lithium hydroxide mixture requires 31.20 mL of 0.3315 M HCl for its titration to the equivalence point. What is the mass percent lithium hydroxide in this mixture? 1.) 0.03120 L x 0.3315= 0.010343 moles HCl I'm not sure where I go ...

chemistry
What is the volume of 3.11×10 to the power 23. Molecules of NH3 at S.T.P

Chemistry
Complete and balance these half-equations. Express as net ionic eqn. 1.) Cr2O7(2−) → Cr(3+) (acidic solution) So far, I have: Cr2O7(2−) + 14H + 6e(-) →2Cr(3+) + 7H20 2.) C2O4(2−) → CO2 (acidic solution) Not sure how to do this one. Thank you.

Chemistry
How many grams of NO2 are needed to form 100.0g of HNO3?

Chemistry
How many moles of O2 must react with 0.550 mole ofMethanol?

Chemistry
How many grams of carbon dioxide ctsare produced when 78.0 grams of Methanol rea

organic chemistry
what is this molecule called, a cyclohexane ring with a CH2 group coming off of it? C7H14 Similar in structure to a benzyllic radical without the pi bonds.

chemistry
Write and balance the equation for the reaction between nitric acid and potassium iodide. The products are potassium nitrate, iodine, nitrogen monoxide, and water. 2HNO3 + KI = KNO3 + I + 2NO + H2O (Did I write the equation correctly?)

Chemistry
A metal whose threshold frequency is 1.10×1015 s−1 emits an electron with a velocity of 6.53×105 m/s when radiation of 1.37×1015 s−1 strikes the metal. What is the mass of the electron?

Chemistry
How many (a) calcium ions and how many (b) nitride ions are there in 1.00 mol Ca3N2?

Chemistry
Find the % ionization if the pH of a 0.10 mol/L solution is 4.5

Chemistry
Which must be the same when comparing 1 mol of oxygen gas, O2, with 1 mol of carbon monoxide gas, CO?

chemistry
Which of these elements has the electonic configuration of The energy absorbed or released when an electron is added to a gaseous atom is known as Which of these elements behave partly as an alkaline metal as well as a halogen element? Hydrogen can be obtained economically as ...

Chemistry
Which reagent has been oxidized in the following equation ? H2(g) + N2(g) === NH3(g)

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