Tuesday
June 30, 2015

Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

chemistry
Which element is reduced in the unbalanced reaction below? I− + MnO4− + H+ = I2 + MnO2 + H2O I no reduction occurred in this reaction O H Mn
Thursday, April 16, 2015 by danny

chemistry
In a titration, 4.1 g of an acid (HX) requires 32.8 mL of 0.74 M NaOH(aq) for complete reaction. What is the molar mass of the acid? Answer in units of g/mol.
Thursday, April 16, 2015 by Anonymous

Chemistry
CaCO3 ----------> CaO + CO2 When 45 grams of calcium carbonate decomposes, how many grams of calcium oxide are produced?
Thursday, April 16, 2015 by Andrea

chemistry
0.947 moles of NaC2H3O2 dissolved in 100 mL solution
Thursday, April 16, 2015 by chem

chemistry
How much BaCl2 would be needed to make 250 mL of a solution having same concentration of Cl^- as the one containing 3.78g of NaCl per 100 mL?
Thursday, April 16, 2015 by jaimi

chemistry
How many kg of wet NaOH containing 12% water are required to prepare 60 litre of 0.5N solution?
Thursday, April 16, 2015 by jaimi

chemistry
How much AgCl will be formed by adding 200mL of 5N HCl to a solution containing 1.7g AgNO3?
Thursday, April 16, 2015 by jaimi

Chemistry
What volume (in mL) of 0.55 M Na2SO4 solution is needed to precipitate all the barium, as BaSO4(s), from 15.5 mL of 0.25 M Ba(NO3)2 solution?
Thursday, April 16, 2015 by john

chemistry
in what ratio 0.2M NaCl and 0.1M CaCl2 solutions are to be mixed so that in the resulting solution, the concentration of negative ions is 50% greater than the concentration of positive ions?
Thursday, April 16, 2015 by jaimi

Chemistry
How much heat is required to boil 90.0g of water at its boiling point?
Thursday, April 16, 2015 by Chemistry Boiling point

statistics
The distribution of B.A. degrees conferred by a local college is listed below, by major. Major Frequency English 2073 Mathematics 2164 Chemistry 318 Physics 856 Liberal Arts 1358 Business 1676 Engineering 868 9313 What is the probability that a randomly selected degree is not ...
Thursday, April 16, 2015 by Bob

Chemistry
How much heat is required to raise the temperature of 90.0g of water from its melting point to its boiling point? Can someone please help me set this up, I am so confused
Thursday, April 16, 2015 by Chemistry Heat

Chemistry
How much heat does your body lose when 3.15g of sweat evaporates from your skin at 25 ∘C? (Assume that the sweat is only water.) The heat of vaporization of water at 25 ∘C is 44.0 kJ/mole? Please someone help explain how to set up this problems or how to do it
Thursday, April 16, 2015 by Chemistry Heat

chemistry
25.0 ml of 15% NH4NO3 solution is diluted to 300.0 ml. What is the concentration of the diluted solution? .15% x 25=3.75ml Do I divide by 300ml and that's my answer?
Thursday, April 16, 2015 by Claire

chemistry
2 litre of NH3 at 30°C and at 0.20 atmosphere is neutralized by 134 mL of a solution of H2SO4. Calculate normality of H2SO4
Thursday, April 16, 2015 by jaimi

chemistry
Determine the hydroxide ion concentration in a solution that is 0.0004 M HCl. Answer in units of M. I have no idea how to start, I just need to know what I need to solve for and hoe to set it up, I know the formula pOH^-=-log[OH^-] I just don't know where to plug things in...
Thursday, April 16, 2015 by will

Chemistry
The amount of CaCO3 that is equivalent to all polyvalent metal ions in one liter of water. what is molarity of 100 ppm Mn^2+? What is the ppm of I^-1 in 0.000100 M of BaI2 ? Thank you!
Thursday, April 16, 2015 by Bear

chemistry
what mass of zinc dissolved in dilute HCL will produce 0.15g of hydrogen ? can you explain the steps to sloving this question please
Wednesday, April 15, 2015 by precious

chemistry
A compound has 85 % tin and 15% antimony. How many grams of antimony will be in 50. grams of the compound. My question is do I need to calculate the empirical formula first to do thi? I'm not sure where to start.
Wednesday, April 15, 2015 by Tina

Chemistry
A beam of light with a frequency of 7.61•1015 Hz hits the surface of the metal. What is the velocity of the electron ejected in m/s? (6 pts) How do you find the velocity based only off the frequency?
Wednesday, April 15, 2015 by Nora

chemistry
What is the volume of dry O2 gas at STP, if it had a volume of 5.00 L at 103 kPa and 300 K?
Wednesday, April 15, 2015 by Lee

Chemistry 11 grade -
Hydrogen gas was collected in a gas-collecting bottle with a volume of 30.0 mL by water displacement on a day where the temperature was 24ºC and the barometric pressure was 98.125 kPa. The vapour pressure of water at 24ºC is 2.99 kPa. What would be the volume of ...
Wednesday, April 15, 2015 by Tania

Chemistry
Predict the products of electrolysis in an aqueous solution of FeCl2. Please help. I don't understand how the answer is OH-, O2, H+, H2.
Wednesday, April 15, 2015 by Chase

chemistry
25.0 ml of 15% NH4NO3 solution is diluted to 300.0 ml. What is the concentration of the diluted solution? My Work: Total molar mass of NH4CO3 = 80.052 .15 x 80.052= 12.0078 25.0 ml (12.00 M) = 300.0 ml (c2) 300.19/300.0ml = The concentration is = 1.0M
Wednesday, April 15, 2015 by Anonymous

Chemistry
Suppose you are assigned to prepare a buffer of 0.10M HNO2 (Ka=1.7 x 10^-4) and 0.10M NaNO2 by mixing equal volumes of both solutions. What is the pH of the resultant solution? How would I first start this question? I have no clue what the steps are to be frank.
Wednesday, April 15, 2015 by Janice

Chemistry
A solution is prepared by mixing 37.5 mL of 0.20 M (CH3)3N with 50.0 mL of 0.20 M (CH3)3NHC and then diluting the mixture to a total volume of 100.0 mL. Calculate the pH of resulting solution. So far I have been able solve the mols of the two chemicals. (CH3)3N being 0.20M/....
Wednesday, April 15, 2015 by Mel

chemistry
How many moles of solute are in the following solutions? Part A 250mL of 0.26M acetic acid, CH3CO2H 2.90L of 0.31M NaOH 980mL of 3.5M nitric acid, HNO3
Wednesday, April 15, 2015 by denise

Chemistry
In an alternate universe, electron energies in an atom are found to obey the following equation where n is the principle quantum number: E = 3.0 x 10^(-19) J * nm * (1/n^2) ..where n is the principle quantum number A gas discharge lamp, like the lamps used in lab, contains ...
Wednesday, April 15, 2015 by Nora

Chemistry
A photoelectric experiment is performed by separately shining a laser of 450 nm (blue light) and 560 nm (yellow light) on a metal surface and measuring the number and kinetic energy of the ejected electrons. The threshold frequency of the metal is 6.00•10^14 Hz. a. ...
Wednesday, April 15, 2015 by Nora

chemistry
Calculate the weight in grams of potassium hydrogen phthalate (KHP, KHC2H3O2, MW 202.2 g/mole) required to neutralize 25.00 ml of 0.1 M NaOH solution.
Wednesday, April 15, 2015 by ryan

chemistry
Describe in detail how you would prepare 500 ml of 0.1 M HCl from 6 M HCl stock solution.
Wednesday, April 15, 2015 by ryan

chemistry
Describe in detail how you would prepare 1000 ml of 0.1 M NaOH from 6 M of NaOH stock solution.
Wednesday, April 15, 2015 by ryan

Chemistry
A photoelectric experiment is performed by separately shining a laser of 450 nm (blue light) and 560 nm (yellow light) on a metal surface and measuring the number and kinetic energy of the ejected electrons. The threshold frequency of the metal is 6.00•10^14 Hz. a. ...
Wednesday, April 15, 2015 by Nora

Chemistry
In an alternate universe, electron energies in an atom are found to obey the following equation where n is the principle quantum number: E = 3.0 x 10^(-19) J * nm * (1/n^2) ..where n is the principle quantum number A gas discharge lamp, like the lamps used in lab, contains ...
Wednesday, April 15, 2015 by Nora

math
Elin estimates her probability of passing French 0.6, passing chemistry is 0.8, (a)determine the probability that elin will pass French but fail chemistry (b) pass chemistry but fail French (c) pass both classes (d)fail both classes
Wednesday, April 15, 2015 by sakura

chemistry
How many electrons does the Au+ ion have ? Enter an integer below without any letters or symbols.
Wednesday, April 15, 2015 by danny

Chemistry
Suppose that 18.84 mL of 0.315 M Ca(OH)2 is required to neutralize 18.2 mL of aqueous HCl solution. What is the molarity of the HCl solution? All help is appreciated. Would also like help showing which numbers go where within any equations! Thanks so much!
Wednesday, April 15, 2015 by Radio Active Wear

chemistry
Write a molecular equation for the gas-evolution reaction that occurs when you mix aqueous hydrobromic acid and aqueous potassium sulfide.
Tuesday, April 14, 2015 by Samantha

Chemistry
Determine the hydronium ion concentration in a solution that is 0.00027 M HCl. Answer in units of M. Determine the hydroxide ion concentration in a solution that is 0.00027 M HCl. Answer in units of M. This is a two part question and I have tried multiple times and every time ...
Tuesday, April 14, 2015 by Radio Active Wear

Chemistry
What volume will 3.5g of CO occupy at 17 degrees Celsius and 1875 torr?
Tuesday, April 14, 2015 by JD

Chemistry
For the neutralization reaction involving HNO3 and Ca(OH)2, how many liters of 1.55 M HNO3 are needed to react with 45.8 mL of a 4.66 M Ca(OH)2 solution? 1. 0.137 L 2. 0.0343 L 3. 0.275 L 4. 1.32 L 5. 0.662 L 6. 0.330 L
Tuesday, April 14, 2015 by Radio Active Wear

Chemistry
How many grams of NaF are needed to make 50 mL of a 2% aqueous solution?
Tuesday, April 14, 2015 by Angel Hernandez

Chemistry
If 74.5% of exhaled air is nitrogen, what is the partial pressure of nitrogen in exhaled air. Assume that the total pressure of exhaled air is 760 mmhg.
Tuesday, April 14, 2015 by JD

chemistry
Write a balanced equation for the reaction between perchloric acid and lithium carbonate.
Tuesday, April 14, 2015 by Samantha

Chemistry: Potentiometric Anyalysis
If the pH probe was miscalibrated and reports the pH to be 1 unit higher than the true pH of the solution it is in, would the molar mass you report for the solid acid be higher, lower, or equal to the true molar mass of the acid? This for my post lab write up. I think that the...
Tuesday, April 14, 2015 by Michelle

chemistry
A chemist dissolves 0.097 g of CuSO4 · 5 H2O in water and dilutes the solution to the mark in a 500-mL volumetric flask. A 13.6-mL sample of this solution is then transferred to a second 500-mL volumetric flask and diluted. What is the molarity of CuSO4 in the second ...
Tuesday, April 14, 2015 by Anonymous

Chemistry
What is the maximum mass of H2O that can be produced by combining 84.4 g of each reactant? 4NH3 (g) + 5O2 (g) -----> 4NO (g) + 6H2O (g) ___________ g H2O ?
Tuesday, April 14, 2015 by Spencer

Chemistry
1.How many grams of KCl is in 225 mL of a 0.452 M solution? 2.What volume in mL of 0.555 M solution contains 85.0g Na2SO4? 3.How many grams of CaCl2 would be dissolved in 2.0L of a 0.10 M solution of CaCl2? Can you please show me how to do these problems?
Tuesday, April 14, 2015 by Jamie

Chemistry
What is the maximum mass of H2O that can be produced by combining 71.7 g of each reactant? 4NH3 (g) + 5O2 (g) -----> 4NO (g) + 6H2O (g) ___________ g H2O ?
Tuesday, April 14, 2015 by Tim

chemistry
what are the favored geometrical arrangements for ABn molecules for which the A atom has 2, 3, 4, 5 and 6 pairs of electrons in in its valence shell?'
Tuesday, April 14, 2015 by priscilla

Chemistry
when titrating 50 mL of .10M H2SO45 with .10 M NaOH, how many mL of NaOH will you have added to reach first equivalence point?
Tuesday, April 14, 2015 by Kay

chemistry
carbon dioxide (CO2) gas is produced as a result of the reaction between calcium carbonate and hydrochloric acid. The gas that is produced is collected in a 20 dm3 container. The pressure of the gas is 105 kPa at a temperature of 20 C. What mass of carbon dioxide was produced?
Tuesday, April 14, 2015 by carmen

Chemistry
What is the maximum mass of S8 that can be produced by combining 85.0 g of each reactant? 8SO2 + 16H2S yields 3S8 +16H2O
Tuesday, April 14, 2015 by Tim

Chemistry
A solid weak acid is weighed, dissolved in water and diluted to exactly 50.00 ml. 25.00 ml of the solution is taken out and is titrated to a neutral endpoint with 0.10 M NaOH. The titrated portion is then mixed with the remaining untitrated portion and the pH of the mixture is...
Tuesday, April 14, 2015 by JUNDY

chemistry
What is the final volume if 125 mL of a stock solution of nitric acid at 10.30 M is diluted to 0.500 M?
Tuesday, April 14, 2015 by Anonymous

Chemistry
The heat of fusion of a metal is 5.53 J/g at its freezing (melting) point of 559◦F. How much of this solid metal (already at 559◦F) can be melted if 3382 J of energy are available? Answer in units of g. I don't know how to set up the problem
Tuesday, April 14, 2015 by Emma

Chemistry
I am working on a five-part question and I just need help with the last part. I'm not sure where to begin with that one. I pasted the question and answers (for a-d) to the other parts below. Thank you! Consider the proposed mechanism for the reaction between nitrogen ...
Tuesday, April 14, 2015 by Lisa

Chemistry
Calculate delta g and Kp for the following equilibrium reaction. Keep getting 7.2E-81 and the answer is 4.5E-81 Why?
Tuesday, April 14, 2015 by C

Chemistry
2H2O(g)<-> 2H2(g) + o2 Calculate delta g and Kp for the following equilibrium reaction. Keep getting 7.2E-81 and the answer is 4.5E-81 Why?
Tuesday, April 14, 2015 by MAn

Chemistry
The electrophoresis of a mixture of histidine (His), aspartic acid (Asp) and phenylalanine (Phe) is carried out at a pH of 5.91. Match the amino acid to its predicted behaviour under electrophoresis at that pH. 1. This amino acid will bear no net charge at pH 5.91 and so will ...
Tuesday, April 14, 2015 by Jessica

chemistry
One mole of an ideal gas is expanded from a volume of 1.00 atm. How much work (in joules) is performed on the surroundings? Ignore sig figs for this problem. (T=300 K; 1 L*atm=101.3 J)
Tuesday, April 14, 2015 by Carolyn

Chemistry
The density of whole blood is 1.05g/mL. A typical adult has about 5.5L of whole blood. What is the mass in pounds of this amount of whole blood?
Tuesday, April 14, 2015 by Anonymous

Chemistry
It has been determined that the body can generate 5500 kJ of energy during one hour of strenuous exercise. Perspiration is the body's mechanism for eliminating this heat. How many liters of water would have to be evaporated through perspiration to rid the body of the heat ...
Tuesday, April 14, 2015 by Jamie lee

chemistry
d(g)--->3/2 e(g)+5/2 f(g) when e increases by .25 mol/l*s how fast is f increasing
Tuesday, April 14, 2015 by kim

Chemistry
What mass of oxygen is needed for the complete combustion of 2.10×10−3g of methane? Express your answer with the appropriate units.
Tuesday, April 14, 2015 by Brittany

Chemistry
What mass of water is produced from the complete combustion of 2.10×10−3g of methane? Express your answer with the appropriate units.
Tuesday, April 14, 2015 by Brittany

Chemistry
What mass of carbon dioxide is produced from the complete combustion of 2.10×10−3g of methane? Express your answer with the appropriate units.
Tuesday, April 14, 2015 by Brittany

Chemistry
Consider the reaction 2D2(g)+O2(g)→2D2O(l) What is the mass of heavy water, D2O(l), produced when 7.65g of O2(g) reacts with excess D2(g)? Express your answer with the appropriate units.
Tuesday, April 14, 2015 by Brittany

Chemistry
Balance the given chemical equation using whole-number coefficients. ?D2(g)+?O2(g)→?D2O(l) Enter the coefficients in order separated by commas (e.g., 1,3,2, where 1 indicates the lack of a coefficient).
Tuesday, April 14, 2015 by Brittany

Chemistry
How many molecules (not moles) of NH3 are produced from 1.17×10−4g of H2? Express your answer numerically as the number of molecules.
Tuesday, April 14, 2015 by Brittany

Chemistry
How many grams of H2 are needed to produce 11.80g of NH3? Express your answer numerically in grams.
Tuesday, April 14, 2015 by Brittany

Chemistry
In the Sandwich Shop, select the "Cheese sandwich" option and observe the equation given for the preparation of a cheese sandwich. In the equation, set the number of bread slices to "2" and the number of cheese slices to "1." You will see that the...
Tuesday, April 14, 2015 by Brittany

Chemistry
Find the number of moles of water that can be formed if you have 226mol of hydrogen gas and 108mol of oxygen gas. Express your answer with the appropriate units.
Tuesday, April 14, 2015 by Brittany

Chemistry
To identify a diatomic gas (X2), a researcher carried out the following experiment: She weighed an empty 2.7-L bulb, then filled it with the gas at 1.30atm and 30.0 ∘C and weighed it again. The difference in mass was 3.9g . Identify the gas.
Tuesday, April 14, 2015 by Anonymous

Chemistry
The electrophoresis of a mixture of histidine (His), aspartic acid (Asp) and phenylalanine (Phe) is carried out a pH of 5.91. What amino acid will This bear no net charge at pH 5.91 and so will remain at the origin, carry a net negative charge at pH 5.91 and so will migrate ...
Tuesday, April 14, 2015 by Jessica

Chemistry
An aqueous solution of a monoprotic acid is prepared. This acid is known to have a pKa of 8.6. If the acid is 37.5% ionized when in solution, what is the pH of the solution? Not really sure where to start with this question? Thanks in advance
Tuesday, April 14, 2015 by Jessica

chemistry
A helium balloon is filled to a volume of 5.60 L at 25∘C. What will the volume of the balloon become if it is put into liquid nitrogen to lower the temperature of the helium to 77 K? A helium balloon is filled to a volume of 5.60 at 25. What will the volume of the ...
Monday, April 13, 2015 by Nadia

chemistry
How many grams of ice at -14.3∘C can be completely converted to liquid at 24.8∘C if the available heat for this process is 4.75×103kJ ?
Monday, April 13, 2015 by Atina

chemistry
How many moles of P4O10 can be produced with 9.544 x 10^-1 moles of the limiting reagent?
Monday, April 13, 2015 by Alli

organic chemistry
Why two immiscible liquids will boil at at a lower temperature than the boiling points of either pure component
Monday, April 13, 2015 by josef

chemistry
A solution of a substance was spotted at a distance 0.5cm from the base of a 20cm long chromatographic plate.Upon elution,the solvent front got to a place 0.5cm from the top of the plate.If the component moves half way up the 20cm plate,calculate its Retention factor value.(...
Monday, April 13, 2015 by Sirneij

Chemistry
How many grams of solid zinc metal will completely react with 100.0 mL of 0.0525 M HCl, if zinc chloride and hydrogen gas are the only products?
Monday, April 13, 2015 by Anonymous

chemistry
How much heat is produced by the complete reaction of 5.91kg of nitromethane?
Monday, April 13, 2015 by john

chemistry
Aqueous ammonia is commercially available at a concentration of 16.0 M. Part A How much of the concentrated solution would you use to prepare 500.0mL of a 1.30M solution?
Monday, April 13, 2015 by d

chemistry
How many grams of MgCl2 is needed to make 1200ml of a .25M solution? .25M/L* 1200mL/1* 1L/1000mL* 95.211:-/ mol I got 28.563g
Monday, April 13, 2015 by sarah

chemistry
What is the molarity of a solution 12.5 naoh dissolved in total volume of 625ml? NaOH = 12.5/molar mass of NaOH = 12.5/39.99 = 0.313 molarity = no.of moles/volume in L = 0.313/0.625 = 0.501 moles/L
Monday, April 13, 2015 by sarah

chemistry
15.87 g of KBr is dissolved in 125.0ml of water. What is the % w/o 15.87/125.0 * 100 = 13%
Monday, April 13, 2015 by sarah

chemistry
What is the % of a solution containing 18.0g of NaCl in 65 ml of water 18.0/65 * 100 = 27% Right? Wrong?
Monday, April 13, 2015 by sarah

chemistry
. How many mL of acetic anhydride (D= 1.082 g/mL) would be needed as starting material to produce 45.0 g of aspirin
Monday, April 13, 2015 by nouma

Biology, Chemistry
I know how to carry out an absorption spectrum I just need help on how to to prepare my test tubes and what to put in then. I am very confused and any help would be greatly appreciated. THANKS ! You will be given a sample containing an unknown concentration of protein (Bovine ...
Monday, April 13, 2015 by Arooj

Chemistry (please Help!!)
determine which experiences a lower effective nuclear charge. using words and/ or drawings explain why. A) an electron in a 2s or an electron in a 2p B) a valence electron on sulfure or a vance electron on silicon C) a valence electron on chlorine or a valence electron on ...
Monday, April 13, 2015 by alia

Chemistry
Consider the following description of a voltaic cell: A 1.0 M solution of Ni(NO3)2 is placed in a beaker with a strip of nickel metal. A 1.0 M solution of SnSO4 is placed in a second beaker with a strip of Sn. The two beakers are connected byba salt bridge and the two ...
Sunday, April 12, 2015 by Noah

chemistry
a chemist puts 50g of chemical a in beaker 1 and 25 g of chemical b in beaker 2 she places bot beaker into a larger container. as the chemicals evaporated the gas react into a white solid what mass of solid will form if chemicals react
Sunday, April 12, 2015 by Anonymous

Chemistry
At room temperature (25 °C), the gas ClNO is impure because it decomposes slightly according to the equation 2ClNO(g) Cl2(g) + 2NO(g) The extent of decomposition is about 4%. Based upon this, what is the approximate value of ΔG°298 for the reaction at that ...
Sunday, April 12, 2015 by Jane

Chemistry
Given these reactions and their corresponding ΔG° values, Glucose + phosphate → glucose-6-phosphate + H2O; ΔG° = +13.13 kJ ATP + H2O → ADP + phosphate; ΔG° = -32.22 kJ What is the calculated ΔG° for the coupled reaction Glucose...
Sunday, April 12, 2015 by Jane

Chemistry
Calculate Keq for 2 moles of electron(s) in each half-reaction and a standard potential of 0.55 V.
Sunday, April 12, 2015 by JUNDY

Chemistry
Calculate ΔGo (in J) for 2 moles of electron(s) in each half-reaction and a standard potential of 0.57 V.
Sunday, April 12, 2015 by JUNDY

Chemistry
A half-cell that consists of a copper wire in 1.00 M CuNO3 solution is connected by a salt bridge to a half cell containing a 1.00 M X(II) acetate solution and an electrode of metal X. The voltage of the cell is 2.00 V, with metal X as the positive electrode. Calculate the ...
Sunday, April 12, 2015 by JUNDY

Chemistry
What is the oxidation state assigned to Cr in zinc dichromate, ZnCr2O7?
Sunday, April 12, 2015 by JUNDY

Chemistry
Identify the correct statement for the following reaction: Br2 (l) → Br2 (g) ΔH° = 30.9 kJ ΔS° = 93.2 J/K A) The reaction is always spontaneous. B) The reaction is never spontaneous. C) The reaction is at equilibrium; therefore, ΔG° = 0. D) The...
Sunday, April 12, 2015 by Chase

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