Recent Homework Questions About Chemistry
When 2016 J of heat energy is added to 49.5 g of ethanol, C2H6O, the temperature increases by 16.6 °C. Calculate the molar heat capacity of C2H6O. 49.5g = 2.98mols C=q/n*temperature change in Celsius 2016/2.98*16.6
Sunday, October 19, 2014 at 3:43pm
when 2g of NaOH were dissolved in 149 g of H2o in a calorimeter at 24 degrees C the temperature of the solution went up to 29 degrees C. If the calorimeter constant was 11 cal/C find delta H for the solution of one mole of NaOH in H2O
Sunday, October 19, 2014 at 3:29pm
What is the pH of a solution of a monoprotic acid with a pKa of 6.6 if it is 39.3 % ionized in solution? Just provide the numerical answer, do not prefix with pH. Give your answer to two decimal places. Remember the definition of Ka
Sunday, October 19, 2014 at 12:02pm
How many milliliters of a 0.200 M HI solution are needed to reduce 21.5 mL of a 0.365 M KMnO4 solution according to the following equation: 10HI+2KMnO4+3H2SO4 ---> 5I2+ 2MnSO4 +K2SO4+ 8H2O
Saturday, October 18, 2014 at 10:41pm
Weight of empty crucible and cover = 23.104 g Weight of crucible, cover, MgO and Mg3N2 = 24.199 g Weight of crucible, cover, MgOand addition of H2O and heat = 24.290 Calculate the number of moles of Mg3N2.
Saturday, October 18, 2014 at 8:28pm
Is there a reaction between Sodium Acetate and Copper (II) Nitrate. If so, what is the balanced equation for it? Also, what type of reaction is it does it form a precipitate?
Saturday, October 18, 2014 at 8:21pm
In a constant-pressure calorimeter, 50.0 mL of 0.300 M Ba(OH)2 was added to 50.0 mL of 0.600 M HCl. The reaction caused the temperature of the solution to rise from 21.73 °C to 25.82 °C. If the solution has the same density and specific heat as water, what is ΔH ...
Saturday, October 18, 2014 at 8:04pm
When a 5.00-g sample of KCN is dissolved in water in a calorimeter that has a total heat capacity of 2.642 kJ·K1, the temperature decreases by 0.340 K. Calculate the molar heat of solution of KCN.
Saturday, October 18, 2014 at 7:25pm
I'm looking for a chemistry and applied chemistry textbook that had been published between 2011-2014. Please help because I couldn't find one on google.
Saturday, October 18, 2014 at 6:37pm
which of the following is consistent with the line spectrum of the hydrogen atom? one of the choices is the nucleus is udnergoing gamma decay. but this si not one of the answers. Im just wondering what kind of decay happens?
Saturday, October 18, 2014 at 4:24pm
You need 715 mL of a 45% alcohol solution. On hand, you have a 55% alcohol mixture. How much of the 55% alcohol mixture and pure water will you need to obtain the desired solution?
Saturday, October 18, 2014 at 3:06pm
Determine the missing values of deltaH in the diagram shown below ^ | ^ N2O3(g) + 1/2 O2(g) (Enthalpy)| | ^ | | deltaH= +16.02 | | | | | | 2 NO2(g) | | | ^ | |deltaH=? | | | | | | deltaH=?| | | | | | | | N2(g)+202(g) | Answer: Delta H for the right= 66.36 Delta H for the left...
Saturday, October 18, 2014 at 2:21pm
Situation: You have 100ml of isotopically labelled water 3H2o. That is, the water is made with the radioactive isotope of hydrogen, tritium, 3H. Compounds that contain radioactive isotopes are called "hot." You pour this 100 mL of "hot" water into the ocean...
Saturday, October 18, 2014 at 1:23pm
What is the maximum velocity (in m/s) acquired by an alpha particle when accelerated between two plates with a potential difference of 580.0 volts? Note: An alpha particle is essentially the nucleus of a helium atom - 2 protons and 2 neutrons.
Saturday, October 18, 2014 at 11:32am
1)What could have caused the impurity in the sodium hydroxide solution? 2)Why was it necessary to dilute the hydrochloric acid before carrying out the titration? This was a question from a titration practical in which we had to dilute HCL then use that along with 25cm3 of NaOH...
Saturday, October 18, 2014 at 5:38am
A dilute solution of sulfiric acid is added to 15g of copper and iron mixture. a) the volume of h2 envolved at standard conditions is 4.48L what is the mass of each of the metals constituting the mixture ? Vm=24l.mol.
Saturday, October 18, 2014 at 5:33am
Table salt, NaCl(s), and sugar, C12H22O11(s), are accidentally mixed. A 4.00-g sample is burned, and 3.30 g of CO2(g) is produced. What was the mass percentage of the table salt in the mixture?
Friday, October 17, 2014 at 7:56pm
Propane (C3H8) which is used as fuel in BBQ tanks often contains some butane(C4H10). A sample of a fuel mixture known to contain both propane and butane occupies a certain volume at a total pressure of 30 mmHg. The sample is then burned completely to produce CO2 and H2O. The ...
Friday, October 17, 2014 at 1:14am
A co-op student designed an experiment to collect hydrogen gas by reacting iron with a hydrochloric acid (HCl) solution. The students co-op supervisor suggested that aluminum can also be included to generate hydrogen gas: Fe + 2 HCl → 2 FeCl2 + H2 2 Al + 6 HCl ...
Friday, October 17, 2014 at 1:12am
A 2.764 g sample containing only iron and aluminum metal was treated with acid to form Al(+3) and Fe(+2). The sample was then titrated with a potassium dichromate solution (only the Fe(II) will react with the dichromate). The sample was found to be equivalent to 14.36 mL of 0....
Thursday, October 16, 2014 at 7:35pm
when 2 moles of potassium chlorate crystals decompose to potassium chloride crystals and oxygen gas at a constant pressure and temperature, 78.0 kj of heat is given off. write a thermodynamic equation for this reaction.I don't know how to set up the equation i know that ...
Thursday, October 16, 2014 at 7:11pm
1/2 H2(g) + 1/2 I2(g) -> HI(g) △H= +28kJ The activation energy for the formation of HI is 167kJ. The activation energy for the decomposition of HI is A. 28kJ B.139kJ C.167kJ D.195kJ I know it is an endothermic reaction.
Thursday, October 16, 2014 at 3:58pm
Please help! I don't understand these questions at all. :( Fe2O3(s) + 2Al(s) -> Al2O3(s) + 2Fe(l) If 0.50 mol of Fe is produced in 10 secs, what is the rate of consumption of Fe2O3 in mol/s? A. 5.0 x 10^-2 mol/s B. 2.5 x 10^-2 mol/s C. 1.0 x 10^-1mol/s D. 5.0 mol/s ...
Thursday, October 16, 2014 at 3:38pm
Increasing the surface area will increase the reaction rate in: 1. N2(g) + O2(g) -> 2NO(g) 2. 2Mg(s) + O2(g) -> 2MgO(s) 3. CaCO3(s) + 2H+(aq) -> Ca2+(aq) + H2O(l) + CO2(g) MY WORK: I think it is 2 & possibly 3. 1 is a homogeneous reaction but is 3 a heterogeneous ...
Thursday, October 16, 2014 at 3:16pm
Calculate the theoretical yield of alum if 0.200g of Aluminum was reacted with excess KOH and H2SO4? I don't even know how to start it. Please help. Also I wanted to say thank you for the help I've gotten from this website it has helped me a lot. I feel like I'm ...
Thursday, October 16, 2014 at 12:48pm
A student determines the iron (II) content of a solution by first precipitating it as iron (II) hydroxide, and then decomposing the hydroxide to iron (II) oxide by heating. How many grams of iron (II) oxide should the student obtain if her solution contains 46.0 mL of 0.426 M ...
Thursday, October 16, 2014 at 11:54am
Twenty grams of aluminum metal at 83.2 C were mixed with 49.3 g of water at 19.7 C. Assuming no heat loss, what was the final temperature of the Aluminum water metal? specific heat for Al= 0.215 specific heat for H2O=1.00
Wednesday, October 15, 2014 at 11:58pm
A 1.07g sample of sulfur was burned in a bomb calorimeter whose calorimeter constant is 2.03 k cal/C. If the resulting temperature change was 1.17 C, what is the molar heat of combustion for sulfur?
Wednesday, October 15, 2014 at 11:56pm
A compound containing boron and hydrogen has been synthesized. You perform two experiments to determine the molecular formula of the compound. A 0.492 g sample of the compound is burned in pure oxygen to produce B2O3 and 0.540 g of water. In the second experiment, when a 63.1 ...
Wednesday, October 15, 2014 at 11:07pm
1) Aqueous solutions of potassium sulfate and ammonium nitrate are mixed together. Which statement is correct? A) Both KNO3 and NH4SO4 precipitate from solution B) A gas is released C) NH4SO4 will precipitate from solution D) KNO3 will precipitate from solution E) No reaction ...
Wednesday, October 15, 2014 at 9:59pm
Balance the following equation. (for a balanced eq. aA + bB → cC + dD, enter your answer as the integer abcd) CrO42−(aq) + H2O(l) + HSnO2− → CrO2−(aq) + OH−(aq) + HSnO3−(aq)
Wednesday, October 15, 2014 at 9:01pm
a 191 g piece of copper is heated to 100 C in a boiling water bath and then dropped into a beaker containing 755 g of water (density =1.00 g/cm3) at 4.0 C. What is the final temperature of the copper and water after thermal equilibrium is reached? (Scu=0.385 J/gK)
Wednesday, October 15, 2014 at 8:22pm
Sodium chloride is formed by the following reaction: NaOH + HCl --> NaCl + H2O How many grams of water are formed when 10 g of HCl is consumed? Round your answer to one decimal place, do not include units or commas. use the molar masses in your text to two decimal places.
Wednesday, October 15, 2014 at 4:00pm
A mixture containing 15 g of carbon and 25 g of oxygen is sealed in a flask. The total mass of the system is 140 g. The flask is then heated to cause the carbon and oxygen to react. The sealed flask is then weighed. What is the final weight of the system?
Wednesday, October 15, 2014 at 2:20pm
A hot air balloon is filled with 1.31 × 106 L of an ideal gas on a cool morning (11 °C). The air is heated to 129 °C. What is the volume of the air in the balloon after it is heated? Assume that none of the gas escapes from the balloon.
Tuesday, October 14, 2014 at 10:25pm
Separation of Racemate- Chemistry Lab
Compare the relative reaction rates of 1-bromobutane, 2-bromopropane, and 2-bromomethylpropane under SN1 reaction conditions. Silver nitrate will be used to provide nitrate ion as the nucleophile to produce alkyl nitrates as products. 1) I found the answer for this one. 2) You...
Tuesday, October 14, 2014 at 9:08pm
When 1.933 g of KNO3 is dissolved in 200 g of water initially at 23.57 ¢ªCelsius in a coffee-cup calorimeter, the final temperature is found to be 22.63 ¢ªCelsius. Calculate the heat released/absorbed per gram of KNO3 and per mol of KNO3 when KNO3 dissolves...
Tuesday, October 14, 2014 at 8:54pm
how could solid magnesium phosphate be prepared and collected using hydrochloric acid, sodium phosphate solution, water and magnesium? For the answer, write a series of steps that describe the procedure and includes a balanced chemical equation for each step
Tuesday, October 14, 2014 at 8:40pm
A 32.3-L of a gas at 30 degrees Celsius and 1.20 atm is to be cooled at constant pressure until its volume becomes 28.4 L. What will be the new gas temperature?
Tuesday, October 14, 2014 at 8:22pm
Separation of Racemate- Chemistry Lab
Compare the relative reaction rates of 1-bromobutane, 2-bromopropane, and 2-bromomethylpropane under SN1 reaction conditions. Silver nitrate will be used to provide nitrate ion as the nucleophile to produce alkyl nitrates as products. 1) You have a choice of acetone or ethanol...
Tuesday, October 14, 2014 at 7:36pm
A pure copper sphere ha a radius of 0.935in. How many moles of copper does it contain? The volume of a sphere is (4/3)3.14r^3, and the density of the copper is 8.96g/cm^3. (1 in. = 2.54cm)
Tuesday, October 14, 2014 at 1:49pm
I was doing a lab and stared off with 10mL of HNO3 and the mass of copper which was 1.5120g. The question now is: With initial mass of copper wire being 1.5120g, calculate the volume of (16M) nitric acid that is required to fully react with the copper. Cu(s)+2HNO3(aq) --> ...
Tuesday, October 14, 2014 at 9:16am
Hi was looking to get some help with an experiment. Currently I trying to determine the amount iron in cereal. And was hoping to get some help with one of the questions I have been given. First off I am the recorded absorbance across the region 470 490 nm for the 3.00 ...
Tuesday, October 14, 2014 at 9:12am
How many moles of solid Mg(OH)2 should you add to 200mL of 0.15M lactic acid solution to produce pH 4.0 buffer? -I don't know how to do this w/0 knowing pKa, but I don't think the point is to look up pKa. Is there some other way to solve this?
Tuesday, October 14, 2014 at 4:28am
Do you expect CaCl(s) to be stable if the 1st ionization energy of Calcium is approx. 590 kj/mol, the Lattice Energy is approx 700 kj/mol and the total change in enthalpy is -36? Why?
Tuesday, October 14, 2014 at 1:44am
A solution of sodium thiosulfate, Na2S2O3, is 0.4206 M. 28.94 mL of this solution reacts with 5.89 mL of I2 solution. What is the molarity of the I2 solution?
Tuesday, October 14, 2014 at 12:22am
How long does it take light to travel each of the following distances 2462 mi, the distance between Los Angeles and New York. How do we calculate how fast light travels?
Monday, October 13, 2014 at 11:00pm
A mixture containing 2.81 g each of CH4 (g), C2H4 (g) and C4H10 (g) is contained in a 1.50 L flask at a temperature of 35 oC. What is the partial pressure (in atm) of C4H10 (g)?
Monday, October 13, 2014 at 9:00pm
What mass (in gram of air) is filled in a hot balloon when it is finflated (at 95oC) to a volume of 500 L at 1.15 atm? (The average molar mass of air is 29 g/mol)
Monday, October 13, 2014 at 8:41pm
You have prepared 20.00 mL of a buffer, using 4.00 mL 0.010 M HA (weak acid) and 3.00 mL 0.010 M NaA (provides A-, the conjugate base of HA). pKa for HA is 6.25. How many moles of HA will be present in the mixture after addition of 0.20 mL 0.010 M NaOH?
Monday, October 13, 2014 at 8:08pm
A standard curve was produced using absorbance values of prepared standards obtained by UV spectrophotometry. The standards were made using concentrated hydrochloric acid as opposed to the 1N HCl that the lab manual says should be used. Because of this my absorbance values are...
Monday, October 13, 2014 at 7:50pm
1) Write the equation for the reaction associated with the Ka2 of sulfuric acid, H2SO4. 2)Write the equation for the reaction associated with the Kb2 of carbonate, CO3^(2-).
Monday, October 13, 2014 at 6:36pm
A 25 mL sample of 0.29 M LiOH analyte was titrated with 0.75 M HI at 25 degree Celsius. 1)Calculate the initial pH before any titrant was added. 2) Then calculate the pH of the solution after 5 mL of titrant was added.
Monday, October 13, 2014 at 6:34pm
Nitric acid, HNO3, was first prepared 1200 years ago by heating naturally occurring sodium nitrate (called saltpeter) with sulfuric acid to produce sodium bisulfate and collecting the vapors of HNO3 produced. Calculate ΔH°rxn for this reaction. ΔH°f[NaNO3(s...
Monday, October 13, 2014 at 6:16pm