Friday
August 28, 2015

Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

Chemistry(Titration)
Why is methyl orange indicator used instead of phenolpthalein when determing calcium content in a chalk by back titration
Wednesday, August 5, 2015 by Kester

college. physics and chemistry and mathematics
An element crystalline in face centred cubic lattice. CCalculate the length of the side of the unit cell if the radius of atom is200pm
Wednesday, August 5, 2015 by nerswn narzary

chemistry
What is the pH of a buffer solution if you have 250 ml of a 1.56M Acetic Acid and you added 26.56 grams of sodium acetate (NaCH3CO2)? What is the new pH if you now add 1gram of NaOH to the buffer solution?
Wednesday, August 5, 2015 by lilly

Chemistry
Determine the mass of PbSO4 produced when 10mL of 0.2M CuSO4 reacts with 10mL of 0.2M Pb(NO3)2? Balance the equation CuSO4 + Pb(NO3)2 → PbSO4 + Cu(NO3)2 Find the number of moles for CuSO4 c=n/v n=c × v n=0.2 × 0.01 n=0.002 mol Since it is a 1:1 ratio, the ...
Wednesday, August 5, 2015 by Kendall

Chemistry
What is the sign of the entropy change for the following reaction, which is the principal process taking place when mortar hardens? Ca(OH)2(s) + CO2(g) ---> CaCO3(s) + H2O(l) Would the sign of entropy be negative since a solid and gas yields a solid and what does it mean by...
Tuesday, August 4, 2015 by D

college chemistry
The air in a typical La Crosse basement contains 53 atoms of 222Rn per liter. A. If the basement has 950 ft^2 of floor space and is 8.0 feet tall, how many 222Rn atoms are there in the whole basement? B. Assuming a total pressure of 1.00 atm, what is the partial pressure of ...
Tuesday, August 4, 2015 by Sara

college chemistry
A piece of wood is discovered in the Amazon with a 14C/12C that is 64.3% that of living organisms. How old is it? I have no clue how to do this please help.
Tuesday, August 4, 2015 by Sam

Chemistry
In this reaction solid NaOH is added to approximately 100 mL of 0.500 mol/L HCl. Trial 1: 2.02 g of solid NaOH is added to 102.0 mL of the HCl solution. The temperature goes from 22.00°C to 32.0°C. Calculate the heat evolved in each trial (Q). I'm confused on how ...
Tuesday, August 4, 2015 by Emily

Urgent Chemistry
The diffusion current for a standard is 1 x 10^-4M solution of hydroquinone is 17.5 microamperes. An unknown solution of hydroquinone, when diluted hundred folds and polarographed under same conditions yielded a current of 30.5 microamperes. Calculate the concentration of ...
Tuesday, August 4, 2015 by Adeola

chemistry
What are the uses of azomethine?
Tuesday, August 4, 2015 by Edward

URGENT CHEMISTRY
1. Write the equilibrium expressions for the following reactions: a) 2 N2O(g) + O2(g)  4 NO(g) b) H2(g) + CO2(g)  H2O(g) + CO(g) c) 4 HCl(g) + O2(g)  2 Cl2(g) + 2 H2O(g) d) 3 H2(g) + N2(g)  2 NH3(g) e) H2(g) + Cl2...
Tuesday, August 4, 2015 by Michael

Chemistry
I really need help with this I am really confused with the law, I have looked at multiple examples and I am still so confused, I know you can't give me the answer, but is there anyway you could please take me through this question step by step? Use Hess's law and ...
Tuesday, August 4, 2015 by Chloe

Chemistry
The percent is confusing me, can you please help me set this equation up. How much heat is liberated when 5.00 kg of coal is burned if the coal is 96.2% carbon by mass and the other materials in the coal do not react? (delta)H comb of carbon is -394kJ/mol thank you
Monday, August 3, 2015 by Syd

chemistry
Please tell me any website....where I can find details of the experiment Reaction of 4-aminotoluene and o-vanillin(for preparation of azomethine)
Monday, August 3, 2015 by Edward

Chemistry
Water is sprayed on oranges during a frosty night. If an average of 11.8 g of water freezes on each orange how much heat is released. Can you please help me set this problem up. I don know what formula to use? thank you
Monday, August 3, 2015 by SS

chemistry
Could you please tell me the objective, theory and mechanism,result, precautions and applications of following experiment : reaction of 4-aminotoluene and o-vanillin(preparation of azomethine)
Monday, August 3, 2015 by Edward

Chemistry
Can you please help me with this problem, I am so confused, and I do not know how to set it up, what equation to use, and what do i need to convert. 1 Transportation Ethanol is being used as an additive to gasoline. The combustion of 1 mol of ethanol releases 1367kJ of energy...
Monday, August 3, 2015 by Syd

Urgent chemistry
Given the following reaction: 3 H2(g) + N2(g) <- -> 2NH3(g) + heat If the following changes were to occur what direction shift will it have (left or right) And what will be the reason of the shift Changes/Stress on system: Decreasing the pressure Adding heat Removing N2
Monday, August 3, 2015 by Nathaly hernandez

NURSING ASAP
Is nursing considered a a science major because I'm taking this course called "CHEM 1001 Chemistry and the World Around Us?" and I studying nursing in college. Please be honest. Thank you! :)
Monday, August 3, 2015 by Sam

Chemistry
1)During an endothermic reaction, total energy A. decreases. B. increases. C. stays the same. D. cannot be determined. 2)The enthalpy of formation of an element is A. negative. B. positive. C. zero. D. negative or positive, depending on which element. i think number 1 is A for...
Monday, August 3, 2015 by Anonymous

Chemistry
Any student is welcome to use this for extra practice and anyone is welcomed to amswed the question. Here is a couple of practice problems a) 2 N2O(g) + O2(g)  4 NO(g) B) H2(g) + CO2(g)  H2O(g) + CO(g) C) 4 HCl(g) + O2(g)  2 Cl2(...
Monday, August 3, 2015 by Cole williams

Chemistry
Given the following reaction: 3 H2(g) + N2(g) <- -> 2NH3(g) + heat If the following changes were to occur what direction shift will it have (left or right) And what will be the reason of the shift Changes/Stress on system: Adding NH3 Decreasing the pressure Adding heat ...
Monday, August 3, 2015 by Sarah foster

Chemistry
Given the following reaction: 3 H2(g) + N2(g) <- -> 2NH3(g) + heat If the following changes were to occur what direction shift will it have (left or right) And what will be the reason of the shift Changes/Stress on system: Adding NH3 Decreasing the pressure Adding heat ...
Monday, August 3, 2015 by Sarah foster

Chemistry
1.00g of oxygen combine with 0.126 g of hydrogen to form H2O. 1.00 g of nitrogen combie with 0.216 g of hydrogen to form ammonia. Predict the weight of oxygen required to combine with 1.00 g nitrogen to form an oxide.i m a student
Monday, August 3, 2015 by Rao

Chemistry
1.00g of oxygen combine with 0.126 g of hydrogen to form H2O. 1.00 g of nitrogen combie with 0.216 g of hydrogen to form ammonia. Predict the weight of oxygen required to combine with 1.00 g nitrogen to form an oxide.
Monday, August 3, 2015 by Rao

Chemistry
In a constant-pressure calorimeter, 65.0 mL of 0.330 M Ba(OH)2 was added to 65.0 mL of 0.660 M HCl. The reaction caused the temperature of the solution to rise from 24.28 °C to 28.78 °C. If the solution has the same density and specific heat as water, what is ΔH ...
Sunday, August 2, 2015 by Emily

chemistry
calculate the mole fraction of ethylene glycol in a solution containing 20% of ethylene glycol prepared in water. answer it as fast as possible.........
Sunday, August 2, 2015 by raksha

Chemistry
How many moles of Ag2CrO4 will be produced from 6 moles of AgNO3?
Saturday, August 1, 2015 by Andrea

Chemistry
Explain why a catalyst speeds up a chemical reaction.
Saturday, August 1, 2015 by Tais

chemistry
If 25ml of 3M HNO3 AND 75ml of 4M HNO3 ar
Saturday, August 1, 2015 by murtaza

Organic chemistry
What type of alcohol is used in the production of alcoholic beverages?
Saturday, August 1, 2015 by Kester

Chemistry
What is the correct order of increasing acidity of the following acids;HF,HI,HCl,HClO4 and HBr.
Saturday, August 1, 2015 by Anonymous

Chemistry
A sample of nitric acid has a density of 1.42g/cm3 and contains 69.5% by weight of the pure acid.What is the molarity of the solution?
Saturday, August 1, 2015 by Kester

Chemistry extra tips
What is the correct IUPAC name for the following 2 compounds? Compund 1) MnO3 Compund 2) N2O Must use a Roman Numeral in name Must use prefixes in name
Friday, July 31, 2015 by Tais

chemistry
HCOOH + CaCO3 will give what (what are the products)
Friday, July 31, 2015 by danielle

Emergency chemistry
PLEASE PLEASE PLEASE ANSWER MY PREVIOUS QUESTIONS
Thursday, July 30, 2015 by Sarah foster

Chemistry
Given the following reaction: XBO3(s) <--> XO(s) + BO2(g) If the concentration of BO2 at equilibrium was 2.0 M, what is the equilibrium constant (K)? Select one: a. Not enough information is given b. 1.0 M c. 2.0 M d. 0.50 M
Thursday, July 30, 2015 by Sarah foster

Chemistry :(
Question text Given the following exothermic, equilibrium reaction: 3 H2(g) + N2(g) <--> 2NH3(g) Using Le Chatelier's Principle, which of the following changes would shift the equilibrium toward more production of NH3? Select one: a. Adding a catalyst b. Adding heat ...
Thursday, July 30, 2015 by Jimmy mendoz

Chemistry
Given the following exothermic, equilibrium reaction: 3 H2(g) + N2(g) <--> 2NH3(g) Using Le Chatelier's Principle, which of the following changes would shift the equilibrium toward more production of NH3?
Thursday, July 30, 2015 by Jimmy mendoz

chemistry
find the mole fraction of 10g/l aquous solution H2So4 having density 0.01 g/ml
Thursday, July 30, 2015 by Hariom

chemistry
A reaction proceeds by the following three-step mechanism with elementary rate coefficients, k. A + B → C k 1 C → A + B k -1 C → B + D k 2 (C is a chemical radical) (ii) By applying the Steady State Approximation determine the overall order of the reaction. (...
Thursday, July 30, 2015 by jay

Chemistry
The formula for magnesium carbonate is MgCO3. What is the charge of the cation in Ag2CO3? Would it be +1 or +2 because there are two of Ag?
Wednesday, July 29, 2015 by Angel

Chemistry
Carbon tetracholoride is made according to the following reaction: carbon disulfide + chlorine gas yields carbon tetrachloride and disulfur dichloride. Write the correct balanced equation and then determine how many grams of CS2 are needed to make 16 kilograms of CCl4. Ok so ...
Tuesday, July 28, 2015 by Dilcia

Chemistry
Carbon tetracholoride is made according to the following reaction: carbon disulfide + chlorine gas yields carbon tetrachloride and disulfur dichloride. Write the correct balanced equation and then determine how many grams of CS2 are needed to make 16 kilograms of CCl4.
Tuesday, July 28, 2015 by Kenneth

Chemistry
Given the balanced equation : 3 CO + 7 H2 -> C3H8 + 3 H2O How much C3H8 will be produced if 45.8 g CO reacts with 87.3 H2 ? Please all your work (i did it but im not sure if i did all the work right)
Tuesday, July 28, 2015 by Dilcia

Chemistry
Carbon tetracholoride is made according to the following reaction: carbon disulfide + chlorine gas yields carbon tetrachloride and disulfur dichloride. Write the correct balanced equation and then determine how many grams of CS2 are needed to make 16 kilograms of CCl4. (...
Tuesday, July 28, 2015 by Dilcia

Chemistry
Determine the concentration at equilibrium if you start with 4.65 grams of Hydrogen and 200 grams of Iodine in a 4.55 liter container. If you now add an extra 1.25M of I2 after equilibrium, calculate Qc. Recalculate now what the concentrations should be at equilibrium. H2(g...
Tuesday, July 28, 2015 by Jessica

chemistry
What is the volume, in L, occupied by 3.260 moles of NO2 gas at STP conditions?
Tuesday, July 28, 2015 by Mindy

chemistry
A fixed amount of CH4 gas occupies a volume of 136 mL at a pressure of 567 mm Hg and a temperature of 19oC. What will be the volume, in mL, occupied by this sample of CH4 gas when the pressure is decreased to 421 mm Hg while holding the temperature constant?
Tuesday, July 28, 2015 by Mindy

chemistry
Consider the following chemical reaction: 2 KNO3 (s) ------------> 2 KNO2 (s) + O2 (g) What volume, in liters, of O2 at 31.2oC and 2.045 atm pressure can be produced from the decomposition of 54.92 g of KNO3 (FM = 101.1 g/mol).
Tuesday, July 28, 2015 by Mindy

chemistry
What is the volume, in L, occupied by 1.20 moles of C2H6 gas at a temperature of 125oC and at a pressure of 1.55 atm?
Tuesday, July 28, 2015 by Mindy

chemistry
A pressurized can of paint contains a fixed mass of gas at an internal pressure of 1.258 atm at 24.8oC. Suppose the can is able to withstand an internal pressure of 2.410 atm before it explodes. At what temperature, in degrees Celsius, will this can explode? HINT: The can is a...
Tuesday, July 28, 2015 by Mindy

chemistry
The combined gas law can be rearranged to solve for T2. In which of the expressions given below has the combined gas law correctly been rearranged to solve for T2?
Tuesday, July 28, 2015 by Mindy

chemistry
The barometric pressure recorded by a weather balloon is 0.731 atmoshperes (atm). Express this barometric pressure in millimeters of mercury (mm Hg).
Tuesday, July 28, 2015 by Mindy

chemistry
Calculate the density of C2H2 gas (FM = 26.04 g/mol), in g/L, at a pressure of 2.082 atm and at a temperature of 62.5oC.
Tuesday, July 28, 2015 by Mindy

chemistry
A 12.8 L sample of Ne gas initially has a temperature of 32.7oC at a pressure of 2.57 atm. What is the new pressure, in atm, if the volume is changed to 10.6 L and the temperature is decreased to 13.9oC?
Tuesday, July 28, 2015 by Mindy

Chemistry
A Mylar Happy Birthday balloon contains 5.15 L of helium gas at 19.4oC. If the pressure remains constant, what will be the volume of helium in the balloon, in L, when the temperature is increased by 6.6oC?
Tuesday, July 28, 2015 by Mindy

Chemistry
A balloon containing 0.600 mole of SO2 gas has a volume of 275 mL at a certain temperature and pressure. What volume, in milliliters, would a 0.765 mole sample of SO2 gas occupy at the same temperature and pressure conditions?
Tuesday, July 28, 2015 by Mindy

Chemistry
A sample of H2 gas occupies a volume of 565 mL at STP. What, volume, in mL, will this sample of H2gas occupy at a temperature of -17oC and at a pressure of 0.560 atm
Tuesday, July 28, 2015 by Mindy

Chemistry
Is 4786 Jules of heat are transferred to 89 g sample of an unknown material within the initial temperature of 23°C what is the specific heat of the material if the final temperature is 89.5 ° C
Tuesday, July 28, 2015 by Dilcia

Chemistry
How many joules of heat when a 640 g piece of copper cools from 375° C to 26° C
Tuesday, July 28, 2015 by Dilcia

Chemistry
How many joules of heat are required to raise the temperature of 550 g of water from 12°C to 18°C
Tuesday, July 28, 2015 by Dilcia

chemistry
The formula for rust can be represented by Fe2O3. How many moles of Fe are present in 24.6 g of the compound? Please guide me through it thank you!
Tuesday, July 28, 2015 by Michelle

AP Chemistry
The formula for rust can be represented by Fe2O3. How many moles of Fe are present in 24.6 g of the compound?
Tuesday, July 28, 2015 by Michelle

organic chemistry
is 2-pentene a cis or trans? and why? Cis- atleast 2 bulky grps.. Trans-3-4 bulky grps.. cis and trans must contain a double bond. i dont know if its a cis or trans so please enlighten me
Tuesday, July 28, 2015 by EJ

Chemistry
A technician mixes a solution containing silver nitrate with a solution containing sodium chromate. 2.89 g of precipitate is produced (assume silver chromate). Calculate the mass of silver nitrate present in the first solution. Make sure you have the correct number of ...
Monday, July 27, 2015 by Jill

chemistry
How many grams of table sugar (C12H22O11) will be needed to make 3.5 L of a 11.5 M solution?
Monday, July 27, 2015 by Will

chemistry
What volume of 0.5M H2SO4 will exactly neutralise 20cm3 of 0.1MNaOH solution?
Monday, July 27, 2015 by aniekan

chemistry
To what volume should you dilute 47.0 mL of a 5.95 M KI solution so that 27.5 mL of the diluted solution contains 3.50 g of KI?
Sunday, July 26, 2015 by greg

organic chemistry
What does delocalization mean? what is the difference between non delocalizabe and delocalizable? Thank you in advance..
Sunday, July 26, 2015 by Anonymous

Chemistry
What are some errors that can be made in colorimetry?
Sunday, July 26, 2015 by Kendall

Chemistry
What is the empirical formula for a molecule containing 52.20 grams manganese (Mn0 and 3.80 grams of Carbon (c)?
Saturday, July 25, 2015 by CJ

Chemistry
6.00 g of NaOH are dissolved in water to make 4.00 L of solution. What is the concentration of hydronium ions, [H3O+], in this solution?
Saturday, July 25, 2015 by Serge

chemistry
find the molar mass of 7.5gm of a gas occupying 5.8 lt volume at s.t.p.
Saturday, July 25, 2015 by nidhi

chemistry
Epsom salts, a strong laxative used in veterinary medicine, is a hydrate, which means that a certain number of water molecules are included in the solid structure. The formula for Epsom salts can be written as MgSO4 · x H2O, where x indicates the number of moles of H2O ...
Thursday, July 23, 2015 by Tutakumbo

science: chemistry
How many moles of NaOH must be added to 1.0 L of 2.6 M HC3H5O3 to produce a solution buffered at each pH? 1)pH= 4.28 2)pH=pKa
Thursday, July 23, 2015 by Julie

science: chemistry
A buffered solution is made by adding 47.4 g C2H5NH3Cl to 1.00 L of a 0.68 M solution of C2H5NH2. Calculate the pH of the final solution. (Assume no volume change. Assume that all solutions are at 25°C.)
Thursday, July 23, 2015 by Julie

chemistry
is gravimetric analysis or colourimetry more accurate when it comes to precipitation reactions where only around 6g and 100ml of the products are used?
Thursday, July 23, 2015 by Kendall

Physics/ Chemistry
The carbon isotope 14C is used for carbon dating of objects. A 14C nucleus can change into a different kind of element, a neighbor on the periodic table with lower mass, by emitting a beta particle – an electron or positron – plus a neutrino or an anti-neutrino. ...
Wednesday, July 22, 2015 by Anonymous

Chemistry
The activation energy (E*) for a reaction is 195 KJ. If the k for this reaction is 3.46 x 10-5/min at 35oC, what will the temperature be in OF when k is 1.5 x 10-3/min?
Wednesday, July 22, 2015 by Jessica

chemistry
5.85gm of NaCl is dissolved in water and the solution is made up to 0.5 litre. what is the molarity of solution ????
Wednesday, July 22, 2015 by Anonymous

Chemistry
when are you going to use the water displacement method in taking the volume of the object?
Wednesday, July 22, 2015 by Sheena

Chemistry
You mix 45 ml of .20M HCl with 45 ml of .20M KOH in a calorimeter. The temperature of both reactions before mixing is 21.5oC. The temperature rises for the mixture to 22.7oC after mixing. What is the enthalpy change per mole of water produced?
Wednesday, July 22, 2015 by Jessica

Chemistry
What is the heat capacity of 83 g of mercury? Specific heat of mercury = 0.14 J/(g oC)
Tuesday, July 21, 2015 by Mindy

Chemistry
What is the mass, in grams, of a sample of solid zinc if its temperature changes from 25.7oC to 39.0oC when it absorbs 123 J of heat energy? Specific heat of zinc = 0.388 J/(g oC)
Tuesday, July 21, 2015 by Mindy

Chemistry
How many grams of Fe can be heated from 40.0oC to 60.0oC when 20.0 g of Cu cools from 100.0oC to 25.0oC? Specific heat of Fe = 0.444 J/(g oC); specific heat of Cu = 0.382 J/(g oC)
Tuesday, July 21, 2015 by Mindy

Chemistry
Calculate the amount of heat, in kJ, needed to convert 30.0 g of ice at -5.2 oC to liquid water at 58 oC. Specific heat of ice = 2.10 J/(g oC); heat of fusion of ice = 334 J/g; Specific heat of water = 4.18 J/(g oC)
Tuesday, July 21, 2015 by Mindy

Chemistry
If the rate of the reaction is 3.5 x 10-3 at 330 K, and the rate of reaction at 285 K is 5.2 x 10-5 what is the activation energy Ea in KJ/mole?
Tuesday, July 21, 2015 by Jessica

Chemistry II
How many grams of gasoline would you need to burn if you started with a 275 gram piece of ice that started at -25 OC and by the end of the experiment had 100 grams of steam and the rest liquid water?
Tuesday, July 21, 2015 by Cynthia

Chemistry
For a given reaction, the rate constant doubles when the temperature is increased from 27 o C to 49 o C. What is the activation energy?
Tuesday, July 21, 2015 by Melissa

Chemistry
Would gravimetric analysis or colorimetry be more accurate when calculating the percentage yield of a precipitate?
Tuesday, July 21, 2015 by Chiara

chemistry
Arrange the following aqueous solutions in order of decreasing freezing points (lowest to highest temperature): 0.10 m Na3PO4, 0.35 m NaCl, 0.20 m MgCl, 0.15 m C6H12O6 and 0.15 m CH3COOH.
Monday, July 20, 2015 by Natalie

Chemistry
How many milliliters of .200 M NaOH solutions are needed to react with 40.0 mL of a 0.340 M NiCl2 solution? Equation: NiCl2(aq) + 2NaOH(aq) --> Ni(OH)2(s) +2NaCl(aq)
Monday, July 20, 2015 by elle

chemistry
A 8.75-L container holds a mixture of two gases at 23 °C. The partial pressures of gas A and gas B, respectively, are 0.317 atm and 0.755 atm. If 0.100 mol of a third gas is added with no change in volume or temperature, what will the total pressure become?
Monday, July 20, 2015 by sam

Chemistry
25cm^3 H2SO4 is neutralized by 40 cm^3 of 0.03 mol/dm^3 KOH. What is the molar concentration of H2SO4?
Monday, July 20, 2015 by Sarah

Chemistry
9. If 5.40 kcal of heat is added to 1.00 kg of water at 100⁰C, how much steam at 100⁰C is produced? Show all calculations leading to an answer.
Monday, July 20, 2015 by Tisha

chemistry
A 30.0 g sample of water at 10.0°C is mixed with 50.0 g of water at 57.0°C in a calorimeter. Calculate the final temperature of the mixture
Monday, July 20, 2015 by robert

organic chemistry
what is the principle involved in the detection of phosphorus? the visible result of it is canary yellow
Sunday, July 19, 2015 by Anonymous

Organic Chemistry
Consider the weak organic base n-propylamine. The Kb value for this base is 1.3-10^-5, and its pKa is 10.6. At what pH are the "proton on" and "proton off" forms present in equal concentrations? At what pH values would the "proton on" form have ...
Sunday, July 19, 2015 by Lily

science, chemistry
"You run out of brown sugar and decide to use only granulated sugar instead. The cookies come out much thinner than usual. Design a controlled experiment to test your hypothesis *, describing how you would interpret your results. Please limit your response to one ...
Sunday, July 19, 2015 by llau

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