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October 24, 2014

Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

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Chemistry
Moles of Copper in the original .825g of Copper Oxide
Wednesday, October 8, 2014 at 9:38pm

chemistry
How many oxygen atoms are in 0.07 mol of dinitrogen pentoxide (N2O5)? Answer in units of atoms
Wednesday, October 8, 2014 at 9:10pm

Chemistry
if all the macro-molecules are made mainly of the elements CHO, how are they different?
Wednesday, October 8, 2014 at 7:07pm

chemistry
20.0 mL of a 2.2 M lead (II) nitrate solution is mixed with 100.0 mL of a 0.75 M magnesium sulfate solution. What is the concentration of nitrate ions in the resulting solution?
Wednesday, October 8, 2014 at 6:41pm

@ Brady & @ Ms. Sue
I'm gonna change my name.. There are way to many of me (anonymous) out there on the internet. what's a good name for a 13 yo girl who loves chemistry and wants to be a Crime Scene Investigator?
Wednesday, October 8, 2014 at 6:19pm

Chemistry
If one assumes the volumes are additive, what is the concentration, in mol/L, of NO3− in a solution obtained by mixing 263 mL of 0.167 M KNO3, 311 mL of 0.404 M Mg(NO3)2, and 713 mL of H2O?
Wednesday, October 8, 2014 at 5:46pm

Chemistry
What volume of 5.0 M H2SO4 should be diluted to 100mL to prepare a 0.25 M H2SO4 M solution? I know the molar mass of H2SO4 is 98g but I'm not sure where exactly that fits in and how I'm supposed to get it to be diluted. Thank you!
Wednesday, October 8, 2014 at 4:33pm

chemistry
A solution of silver perchlorate (AgClO4) is made by dissolving 40.4 g of pure silver perchlorate and diluting it to exactly 140 ml. What is the solutions molarity? Can you just go through the steps of what I need to do? I'm so confused. Thanks
Wednesday, October 8, 2014 at 4:25pm

Chemistry
Calculate how many grams of O2(g) can be produced from heating 37.0 grams of KClO3(s). Formula: 2KClO3 = 2KCl + 3O2
Wednesday, October 8, 2014 at 4:24pm

chemistry
Calculate how much K3Fe(CN)6 [MW: 329.24] you would need to weigh out to make a 1x10-3 M solution dissolved in 0.2 M NaNO3 in a 100 ml volumetric so far i have worked out that 0.329 g will give me the 1x10-3 M, but im confused when it is dissolved into the NaNO3.
Wednesday, October 8, 2014 at 2:31pm

Chemistry
Assign the two absorptions found above 3000 cm-1 in acetamide. Why are these absorptions missing in n,n-dimethylacetamide
Wednesday, October 8, 2014 at 2:28pm

Chemistry
A gas mixture composed of helium and argon has a density of 0.846g/L at a 734mmHg and 298 K. What is the composition of the mixture by volume?
Wednesday, October 8, 2014 at 1:36pm

Chemistry
A 0.700 g sample containing Ag2O and inert material is heated, causing the silver oxide to decompose according to the following equation: 2 Ag2O(s) → 4 Ag(s) + O2(g) If 13.8 mL of gas are collected over water at 27°C and 1.00 atm external pressure, what is the ...
Wednesday, October 8, 2014 at 1:31pm

Chemistry
Give a acid-base pairs which produce Na2CO3 as a salt
Wednesday, October 8, 2014 at 1:22am

Chemistry
A solution of ammonia and water contains 1.60×1025 water molecules and 8.50×1024 ammonia molecules. How many total hydrogen atoms are in this solution?
Wednesday, October 8, 2014 at 1:11am

chemistry
what could cause the difference in the actual number of mole and the expected number of mole in copper oxide?
Tuesday, October 7, 2014 at 11:13pm

chemistry
what is the molar ratio of 0.114 copper to 0.116 oxygen? Then how do you make an empirical formula from this information?
Tuesday, October 7, 2014 at 11:05pm

chemistry
in a empirical formula lab how do you calculate the number of moles of Cu in 0.0114 moles of CuSo4*H2O? Thanks
Tuesday, October 7, 2014 at 10:38pm

Chemistry
---This was the previous one--- Substances A, B, and C can all act as oxidizing agents. In solution, A is green, B is yellow, and C is red. In the reactions in which they participate, they are reduced to A-, B-, and C- ions, all of which are colorless. When a solution of C is ...
Tuesday, October 7, 2014 at 10:36pm

chemistry
A metal rod has a mass of 17.62 g. A graduated cylinder contains 29.9 mL of water. The metal rod is added to the cylinder. The final water level in the cylinder is 36.1 mL. What is the density of the metal rod?
Tuesday, October 7, 2014 at 10:35pm

chemistry 112
A volume of 60.0mL of aqueous potassium hydroxide (KOH) was titrated against a standard solution of sulfuric acid (H2SO4). What was the molarity of the KOH solution if 19.2mL of 1.50 M H2SO4 was needed? The equation is 2KOH(aq)+H2SO4(aq)→K2SO4(aq)+2H2O(​l) Express ...
Tuesday, October 7, 2014 at 10:34pm

Chemistry
Earlier I asked /display.cgi?id=1412727782 (tyvm btw) Say you have these A, B, and C solutions. Now you have an unknown colorless solution that contains either NaA, NaB, or NaC. In solution, each salt dissociates completely into the Na+ ion and the anion A-,B-, or C- (which ...
Tuesday, October 7, 2014 at 10:15pm

Chemistry
A reaction uses 4.5 grams of oxygen and an excess of nitrogen. How many grams of dinitrogen pentoxide are produced?
Tuesday, October 7, 2014 at 10:13pm

chemistry
How many grams are in 2.5 moles of magnesium hydroxide
Tuesday, October 7, 2014 at 9:36pm

Chemistry
The concentration of a certain sodium hydroxide solution was determined by using the solution to titrate a sample of potassium hydrogen phthalate (abbreviated KHP). KHP is an acid with one acidic hydrogen and a molar mass of 204.22 g/mol. In the titration 34.67 mL of the ...
Tuesday, October 7, 2014 at 8:54pm

Chemistry
A student mixes four reagents together, thinking that the solutions will neutralize each other. The solutions mixed together are 50.0 mL of 0.100 M hydrochloric acid, 100.0 mL of 0.200 M of nintric acid,500. mL of 0.0100 M calcium hydroxide, and 200.0 mL of 0.100 M rubidium ...
Tuesday, October 7, 2014 at 8:52pm

Chemistry
Any help would be greatly appreciated! Substances A, B, and C can all act as oxidizing agents. In solution, A is green, B is yellow, and C is red. In the reactions in which they participate, they are reduced to A-, B-, and C- ions, all of which are colorless. When a solution ...
Tuesday, October 7, 2014 at 8:23pm

CHEMISTRY
If you use a dirty buret, the titrant leaves drops of solution behind as the meniscus descends during delivery of the solution. The volume actually delivered by the buret will be __________ the volume your readings of the buret scale indicate was delivered the same as less ...
Tuesday, October 7, 2014 at 7:38pm

Chemistry
A pure white solid material that looks like table salt releases gas when heated under certain conditions. There is no change in the appearance of the solid, but the reactivity of the material changes. Did a chemical or physical change occur? How do you know? Was the original ...
Tuesday, October 7, 2014 at 6:22pm

chemistry
Calculate the air concentration (mol/l) of phenol in equilibrium with solution including 100 g/m3 of phenol.(T=20 C)
Tuesday, October 7, 2014 at 6:04pm

chemistry
An experiment to determine compound partition among air, water, and soil phases was conducted by adding 1 gram of the compound to a reactor that had 1 m3 of air, 0,001 m3 of water0 and 100 g of solid. The reactor was at atmodpheric pressure and at aconstant tepmrature 20 C The...
Tuesday, October 7, 2014 at 6:03pm

chemistry
If the concentration of pure o-xylene in hair above a pool of pure o-xylene is 200 g/m3 at 25 C which direction can o-xylene move vapor pressure of pure o-xylene is 0.00871 atm
Tuesday, October 7, 2014 at 5:50pm

Chemistry
A fictitious element X is composed of 10.0 percent of the isotope 55^X , 20.0 percent of the isotope 56^X , and 70.0 percent of the isotope 57^X . Calculate the weighted atomic mass of element X to the nearest tenth.
Tuesday, October 7, 2014 at 4:30pm

Chemistry
A hot air balloon is filled with 1.23 × 106 L of an ideal gas on a cool morning (11 °C). The air is heated to 121 °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 7, 2014 at 4:00pm

chemistry
Mass (g) of solute in 179.8 mL of 0.267 M calcium acetate
Tuesday, October 7, 2014 at 3:29pm

Chemistry
I do not know how to solve this problem. Could you show me how? You have a stock solution of 5.00M H3PO4. a.) What would be the concentration if 20.0mL of the stock solution is diluted to 250.0mL? b.) What volume of the dilute solution would you need if you needed 0.0200mol oh...
Tuesday, October 7, 2014 at 1:22pm

Chemistry
The synthesis of zinc iodide was performed using 1.8912g of zinc and 1.5965g of iodine. Determine the limiting reactant and calculate the theoretical yield of zinc iodide in grams.
Tuesday, October 7, 2014 at 12:42pm

Chemistry
What is the enthalpy change for the first reaction? Fe2O3(s) → 2Fe(s) + 3/2O2(g) ΔH = 4Fe(s) + 3O2(g) → 2Fe2O3 (s) ΔH = -1,652 kJ I think I'm supposed to rearrange the equation and double everything but enthalpy isn't my strong suit
Tuesday, October 7, 2014 at 12:19pm

CHEMISTRY 56
Aerosol cans have a label that warns the user not to use them above a certain temperature and not to dispose of them by incineration. Even an empty can contains residual gaseous propellant. For example, the residual pressure in a can is 1.16atm when it is sitting on a shelf at...
Tuesday, October 7, 2014 at 10:27am

CHEMISTRY
what do you observe on the seawater where ships dock? Explain in relation with attractive forces and surface tension..
Tuesday, October 7, 2014 at 12:57am

CHEMISTRY
what do you observe if you drop water to a basin of water? Explain please
Tuesday, October 7, 2014 at 12:56am

chemistry
the reaction of 7.10g carbon with excess O2 yields 12.25g of CO2. what is the percent yield of this reaction? I have tried everything and looked through all of my notes and nothing is working for stiochiometry
Monday, October 6, 2014 at 11:06pm

Chemistry
A given solution contained potassium chloride, KCl, and hydrochloric acid. 25 cm3 of it needed 24.80 cm3 of 0.0986 M sodium hydroxide solution to neutralize the acid, and the neutral solution then required 23.55 cm3 of 0.2 M silver nitrate, AgNO3, solution to precipitate all ...
Monday, October 6, 2014 at 10:15pm

Chemistry
It takes how many ml of 1.5 M NaCl to make 500 ml of .38 M NaCl?
Monday, October 6, 2014 at 10:05pm

chemistry
A 26.6 g sample of an unknown compound contains 0.8 g of oxygen. What is the percent by mass of oxygen in the compound?
Monday, October 6, 2014 at 9:56pm

chemistry
Magnesium combines with oxygen to form magnesium oxide. If 20.07 g of magnesium reacts completely with 6.70 g of oxygen, what is the percent by mass of oxygen in magnesium oxide?
Monday, October 6, 2014 at 9:56pm

chemistry
Copper sulfide is formed when copper and sulfur are heated together. In this reaction, 132 g of copper reacts with 53 g of sulfur. After the reaction is complete, 9 g of sulfur remains unreacted. What is the mass of copper sulfide formed?
Monday, October 6, 2014 at 9:55pm

chemistry
When mercury oxide is heated, it decomposes into mercury and oxygen. If 26.8 g of mercury oxide decomposes, producing 1.8 g oxygen, what is the percent by mass of mercury in mercury oxide?
Monday, October 6, 2014 at 9:52pm

Chemistry
Classify each as carbohydrate, protein, lipid, or nucleic acid. 1. Starch 2. Cholesterol 3. Steroids 4. Glycogen
Monday, October 6, 2014 at 8:15pm

chemistry
How many moles of molecules are in 198 g of hydrogen nitrate (HNO3)? Answer in units of mol
Monday, October 6, 2014 at 8:01pm

Chemistry
The solubility of KNO3 is 80g/100g water at 50 degrees and 10g/100g water at 0 degrees. The solubility of CuSO4 is 60g/100g water at 50 degrees and 20g/100g water at 0 degrees. A mixture contains 13.8g of KNO3 and 1.94g of CuSO4. A) Calculate the minimum mass of water that ...
Monday, October 6, 2014 at 7:52pm

chemistry
A 22.0 g piece of alloy at 264.8°C is dropped into a simple calorimeter that contains 175.0 g of water. The temperature of the calorimeter water increased from 20.4°C to 23.1°C. Calculate the specific heat capacity of the alloy.
Monday, October 6, 2014 at 7:49pm

CHEMISTRY 45
Calculate the average speed of an oxygen gas molecule, O2, at 21.0∘C . ------------------------- How much faster do ammonia (NH3) molecules effuse than carbon monoxide (CO) molecules? --------------------------- Highest rate of effusion to lowest rate He, H2S, C3H8, Ar, H2
Monday, October 6, 2014 at 7:47pm

CHEMISTRY 44
A syringe containing 1.65mL of oxygen gas is cooled from 91.3∘C to 0.5∘C. What is the final volume of oxygen gas? I got 2.19ml???
Monday, October 6, 2014 at 7:45pm

CHEMISTRY 3
Consider the following balanced equation: 2N2H4(g)+N2O4(g)→3N2(g)+4H2O(g) Complete the following table showing the appropriate number of moles of reactants and products. If the number of moles of a reactant is provided, fill in the required amount of the other reactant, ...
Monday, October 6, 2014 at 4:16pm

Principles of Chemistry
A certain amount of chlorine gas was placed inside a cylinder with a movable piston at one end. The initial volume was 3.00 L and the initial pressure of chlorine was 1.30atm . The piston was pushed down to change the volume to 1.00 L. Calculate the final pressure of the gas ...
Monday, October 6, 2014 at 3:38pm

CHEMISTRY 2
A 56.0mL sample of a 0.102 M potassium sulfate solution is mixed with 34.7mL of a 0.114 M lead acetate solution and this precipitation reaction occurs: K2SO4(aq)+Pb(C2H3O2)2(aq)→PbSO4(s)​+2KC2H3O2(aq) The solid PbSO4 is collected, dried, and found to have a mass of...
Monday, October 6, 2014 at 2:07pm

CHEMISTRY 1
What is the correct net ionic equation, including all coefficients, charges, and phases, for the following set of reactants? Assume that the contribution of protons from H2SO4 is near 100 %. Ba(OH)2(aq)+H2SO4(aq)→ Express your answer as a chemical equation. This is what ...
Monday, October 6, 2014 at 2:06pm

chemistry
4. If you were asked to determine the number of atoms in a 52.0 gram sample of carbon, how would you set up the conversion? What is the final answer with correct units?
Monday, October 6, 2014 at 1:30pm

Chemistry
How to convert 24.63cm to nm^2
Monday, October 6, 2014 at 11:06am

Chemistry
Report 2 decimal places and appropriate units, the molar mass of steric acid (C17H35COOH). Please help
Monday, October 6, 2014 at 11:04am

Chemistry
How many moles of steric acid are contained in 0.25mL of a hexane solution containing 5.4x10^-4 grams of steric acid/L? (Hint: g/L x L = g/ (g/mol)=mol). Please show your work. Please help. Thank you
Monday, October 6, 2014 at 11:03am

Chemistry
why hcl dissociates more fastly than ether, reason ?
Monday, October 6, 2014 at 10:24am

chemistry
What mass of HCL is present in 0.80 molar, 2500mL solution?
Monday, October 6, 2014 at 9:46am

Chemistry
CH ≡ CH + 2AgNO3 → AgC ≡ CAg + 2HNO3 represents which property of acetylene. A. Basic B Acidic. √ answer is acidic, now i want to ask that how we can know that in this question , acidic is the property of acetylene? help? someonoe told me that more ...
Monday, October 6, 2014 at 9:26am

Chemistry
AgCl <------> Ag+ + Cl- , the Ksp for the reaction will be . Ksp = [Ag+] [Cl-] how?
Monday, October 6, 2014 at 9:25am

Chemistry
Construct a cycle with the following steps: Begin with: 1 mol ideal monatomic gas at 300 K and 1 bar. Point A. 1. Isothermal reversible expansion till volume gets twice its original value. Point B. then, 2. Irreversible adiabatic expansion against P_ext=0.25 bar till P_ext=...
Monday, October 6, 2014 at 4:59am

Chemistry
Report 2 decimal places and appropriate units, the molar mass of steric acid (C17H35COOH). Thank you
Monday, October 6, 2014 at 4:14am

Chemistry
How many moles of steric acid are contained in 0.25mL of a hexane solution containing 5.4x10^-4 grams of steric acid/L? (Hint: g/L x L = g/ (g/mol)=mol). Please show your work. Please help. Thank you
Monday, October 6, 2014 at 3:57am

Chemistry
I need help with two problems need helps please!! 1) Calculate the surface area in nm^2 of a water solution contained in a watch glass with a diameter of 5.6cm. Remember that the area of a circles is calculate as A=πr2 and diameter= 2r 2) If a molecule of stearic acid ...
Monday, October 6, 2014 at 3:53am

chemistry
Al(oH)3+HcL=
Monday, October 6, 2014 at 2:31am

chemistry
Nh3+ch3coo=
Monday, October 6, 2014 at 2:09am

chemistry
A 2.00 gram sample of Copper (II) acetate produced 2.48 grams of a Copper (II) Formate Hydrate. After heating the sample the final mass of the Copper (II) Formate was 1.69 grams. What was the degree of hydration for the Copper (II) Formate?
Monday, October 6, 2014 at 1:59am

Chemistry
A compound contains only potassium and iodine. A sample weighing 12.3 g of this compound contained 2.90 g of potassium. How many grams of iodine would there be in another sample of this compound containing 9.56 g of potassium? Do I find the mol of each (12.3 g, 2.90 g) or am I...
Monday, October 6, 2014 at 1:35am

CHEMISTRY
A sprinter set a high school record in track and field, running 200.0 m in 21.5s . What is the average speed of the sprinter in kilometers per hour?
Monday, October 6, 2014 at 12:58am

Chemistry
A specific brand of gourmet chocolate candy contains 7.00 g of dietary fat in each 22.7-g piece. How many kilograms of dietary fat are in a box containing 4.00lb of candy?
Monday, October 6, 2014 at 12:55am

chemistry
n the spectroscopic analysis of many substances, a series of standard solutions of known concentration are measured to generate a calibration curve. How would you prepare standard solutions containing 10.0, 25.0, 50.0, 75.0, and 100. ppm of copper from a commercially produced ...
Monday, October 6, 2014 at 12:21am

Chemistry
In Europe, gasoline efficiency is measured in km/L. If your car's gas mileage is 38.0mi/gal , how many liters of gasoline would you need to buy to complete a 142-km trip in Europe? Use the following conversions: 1km=0.6214mi and 1gal=3.78L.
Sunday, October 5, 2014 at 11:55pm

CHEMISTRY
How does hydrogen bonding in water affects Density?
Sunday, October 5, 2014 at 11:19pm

CHEMISTRY
Total Pressure in a vessel containing Oxygen collected over water at 25 *C was 723 torr. The Vapor Pressure of water at that Temperature is 23.8 torr. What was the pressure of gas?
Sunday, October 5, 2014 at 11:16pm

chemistry
Discuss how you would seperate Fe+3 from Ca2+
Sunday, October 5, 2014 at 10:19pm

Chemistry
What functional groups do uracil,guanine,cytosine, and tyrosine belong to.
Sunday, October 5, 2014 at 9:35pm

Chemistry
The oxidation of iodide ion by arsenic acid, H3AsO4, is described by the balanced equation 3I−(aq)+H3AsO4(aq)+2H+(aq)→ I3−(aq)+H3AsO3(aq)+H2O(l) If −Δ[I−]/Δt = 4.8×10−4M/s , what is the value of Δ[I3−]/Δt ...
Sunday, October 5, 2014 at 9:33pm

Chemistry
The oxidation of iodide ion by arsenic acid, H3AsO4, is described by the balanced equation 3I−(aq)+H3AsO4(aq)+2H+(aq)→ I3−(aq)+H3AsO3(aq)+H2O(l) If −Δ[I−]/Δt = 4.8×10−4M/s , what is the value of Δ[I3−]/Δt ...
Sunday, October 5, 2014 at 9:18pm

chemistry
A pure gold ring with a volume of 1.88cm3 is initially at 18.4∘C. When it is put on, it warms to 34.3∘C.
Sunday, October 5, 2014 at 9:16pm

Chemistry
What volume of 0.1000 M oxalic acid (a diprotic acid) would be required to completely neutralize 100.00 mL of 0.1000 M NaOH?
Sunday, October 5, 2014 at 8:17pm

Chemistry
The boiling point of diethyl ether CH3CH2OCH2CH3 is 34.500C at 1 atmosphere. A nonvolatile, nonelectrolyte that dissolves in diethyl ether is cholesterol . How many grams of cholesterol, C27H46O (386.6 g/mol), must be dissolved in 208.0 grams of diethyl ether to raise the ...
Sunday, October 5, 2014 at 8:03pm

Chemistry
Naturally occurring copper is a mixture of two isotopes. One of these has 34 neutrons the other has 36. If the relative atomic mass of copper is 63.55 amu calculate the natural abundances (percentages ) of the two isotopes.
Sunday, October 5, 2014 at 7:55pm

Chemistry
What volume of 0.1000 M oxalic acid (a diprotic acid) would be required to completely neutralize 100.00 mL of 0.1000 M NaOH?
Sunday, October 5, 2014 at 7:48pm

Chemistry
A sprinter must average 24.0 mi/h to win a 100-m dash in 9.30 s. What is his wavelength at this speed if his mass is 84.5 kg?
Sunday, October 5, 2014 at 4:44pm

chemistry
What is the percent mass of calcium in a calcium supplement if 1.06 g of calcium carbonate is extracted from a 2.82 g pill
Sunday, October 5, 2014 at 4:30pm

Chemistry
In chemistry, we did a lab in which we had a certain mass of copper, performed multiple experiments on the copper, and at the end, extracted the copper from a solution and weighed it. The goal was that the mass of the final copper should be the same as the mass of the initial ...
Sunday, October 5, 2014 at 4:12pm

chemistry
how many grams of zinc chloride could be formed from the reaction of 3.57 g of zinc with excess HCL
Sunday, October 5, 2014 at 4:09pm

Chemistry Help! (Rydberg Equation)
a) According to the Rydberg equation, the line with the shortest wavelength in the emission spectrum of atomic hydrogen is predicted to lie at a wavelength (in nm) of _____ b) According to the Rydberg equation, the longest wavelength (in nm) in the series of H-atom lines ...
Sunday, October 5, 2014 at 2:45pm

Chemistry
a) A sprinter must average 24.0 mi/h to win a 100-m dash in 9.30 s. What is his wavelength at this speed if his mass is 84.5 kg? b) For potassium metal, the work function W (the minimum energy needed to eject an electron from the metal surface) is 3.68 × 10-19 J. Which ...
Sunday, October 5, 2014 at 2:41pm

CHEMISTRY
Consider the following balanced equation: 2N2H4(g)+N2O4(g)→3N2(g)+4H2O(g) Complete the following table showing the appropriate number of moles of reactants and products. If the number of moles of a reactant is provided, fill in the required amount of the other reactant, ...
Sunday, October 5, 2014 at 12:25pm

Chemistry
c) How many grams of each matter is in 2,0 litres of the following water solutions i) 8,6 til-% ethanol solution ii) 22,6 til-% glycol solution (1,2-ethanediol)
Sunday, October 5, 2014 at 9:48am

chemistry
When 34.1 g of lead reacts with 6.81 L of oxygen gas, measured at 1.00 atm and 25.0°C, 36.1 kJ of heat is released at constant pressure. What is DH° for this reaction?
Sunday, October 5, 2014 at 8:32am

chemistry
Following oxidation-reduction reaction by using the oxidation state method a) O2+H2O+Pb=Pb(OH)2
Sunday, October 5, 2014 at 12:41am

Chemistry
a piece of silver contains 6.42x10^22 how many dozens does it contain
Saturday, October 4, 2014 at 10:15pm

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