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January 30, 2015

Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

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chemistry
In the Bohr model, which is the lowest energy state available for an electron? A. nth B. excited state C. first state D. ground state Im thinking the answer is c or d.
Monday, December 15, 2014 at 6:16pm

Chemistry
The heat of combustion of benzene, C6H6, is -41.74 kJ/g. Combustion of 3.65 of benzene causes a temperature rise of 4.41 C^o in a certain bomb calorimeter. What is the heat capacity of this bomb calorimeter? (kJ/C^o) So, I what I did was I multiplied -41.74 kJ/g and 3.65 to ...
Monday, December 15, 2014 at 6:02pm

chemistry(ppm parts per million)
How would i calculate 2.34 mg x 10^6 divided by 3.50 kg
Monday, December 15, 2014 at 5:35pm

chemistry
A 14 karat gold alloy contains 58% m/m gold. How much of this alloy can a jeweler make using 50.0 g of pure gold?
Monday, December 15, 2014 at 5:13pm

chemistry(solutions)
What is the % w/v of 13.2 g of salt dissolved in 264 mL of solvent?
Monday, December 15, 2014 at 4:17pm

Chemistry
I'm stumped 4ko2 + 2co2 ----2k2co3 + 3o2 What mass of k02 in grams is required to react with 8.90 l at 22.0 c and 767 mm hg? Please help thank you
Monday, December 15, 2014 at 2:54pm

chemistry
If your car gets 21.4 mpg, how many L of CO2, will you release into the atmosphere, if you drove the 1280miles from Towson University to Key West Florida for a much needed break after taking Chemistry 121? Assume 1.05atm and 17.0C. What would your carbon load be in lbs (lbs of...
Monday, December 15, 2014 at 2:33pm

Chemistry
Which electron would have the highest ionization energy for an oxygen atom? A. 2nd B. 1st C. 5th D. 6th If it is the highest I was guessing b or d.
Monday, December 15, 2014 at 2:06pm

chemistry
If your car gets 21.4 mpg, how many L of CO2, will you release into the atmosphere, if you drove the 1280miles from Towson University to key West Florida for a much needed break after taking Chemistry 121? Assume 1.05atm and 17.0C. What would your carbon load be in lbs (lbs of...
Monday, December 15, 2014 at 1:57pm

chemistry
If your car gets 21.4 mpg, how many L of CO2, will you release into the atmosphere, if you drove the 1280miles from Towson University to key West Florida for a much needed break after taking Chemistry 121? Assume 1.05atm and 17.0C. What would your carbon load be in lbs (lbs of...
Monday, December 15, 2014 at 1:54pm

chemistry
A. Orbital shape B. Orientation in the orbital C. Main energy level D. Electron spin
Monday, December 15, 2014 at 1:54pm

chemistry
Under standard conditions for all concentrations, the following reaction is spontaneous at 25 ¢XC with EO = 0.16 V. + - 02 (g) + 4 H (aq) + 4 Br (aq) -+ 2 H20 (I) + 2 Br2 (1) If [H+] is a?justed by adding a buffer of 0.10 M NaOCN and 0.10 M HOCN (Ka = 3.5 x 10 ), what ...
Monday, December 15, 2014 at 12:49pm

chemistry
Malic acid is a weak diprotic organic acid with K1 = 4.0x 10-4 and K2 = 9.0 x 10-6. (a) Letting the symbol H2A represent malic acid, write the chemical equations that represent K1 and K2 . Write the chemical equation that represents K] xK2 . (b) Qualitatively describe the ...
Monday, December 15, 2014 at 12:46pm

Chemistry 120
Calculate the pH of aqueous solution 0.0000019 M KOH
Monday, December 15, 2014 at 12:45pm

chemistry
What is an ionic solid? A. One positive ion and one negative ion bonded to form a solid B. Many nonmetal atoms bonded together to form a solid C. Many positive and negative ions bonded to form a solid D. Many metal atoms bonded together to form a solid I believe the answer is ...
Monday, December 15, 2014 at 12:30pm

Chemistry
What is product form when 2-bromobutane reacts with potassium cyanide in ethanol?
Monday, December 15, 2014 at 12:00pm

Chemistry
A compound D, CH3CHCLCH2CH3 was boiled under reflux for some time with dilute NaOH solution.. Dilute nitric acid was then added to the mixture, followed by dilute silver nitrate solution. A Few drops of concentrated ammonia solution were then added. What observation were ...
Monday, December 15, 2014 at 11:56am

Chemistry
Outline the prepartion of 2-chlorobutane from an alcohol?
Monday, December 15, 2014 at 11:43am

Chemistry
Naturally occurring magnesium consists of Magnesium-24 (23.9850 amu; 78.99%), Magnesium-25 (24.9858 amu), and Magnesium-26 (25.9826 amu). Using the average atomic mass from the periodic table, calculate the closest percent abundance of Magnesuim-26. a) 29.30% b) 8.993% c) 10....
Monday, December 15, 2014 at 10:56am

chemistry
For an atom of sulfur, which electron would require the least amount of energy to remove from the atom? A. 3s2 B. 1s1 C. 3p1 D. 3p4 I think the answer is c or d, preferring d. What would you go with?
Monday, December 15, 2014 at 1:30am

Chemistry
Last question I'm having trouble with. Predict the oxidation # for astatine. Why?
Monday, December 15, 2014 at 12:38am

Chemistry
What is the difference in a polyatomic ion that has its name end in (-ate) as compared to one with the same central element that ends in (-ite)
Sunday, December 14, 2014 at 11:55pm

Chemistry
Which of the following is an example of quantization? A. The amount of time spent in a classroom B. The number of students in a classroom C. Learning happening in a classroom D. The temperature range in a classroom I know I asked this question but I would this paragraph. Is it...
Sunday, December 14, 2014 at 11:54pm

Chemistry
Suppose a student used 28.4 ml of 0.100 M NaOH solution to neutralize the 25.0 ml of the lemon juice sample which contains citric acid (H3A)in it. H3A + 3NaOH -----> Na3A + 3H2O Molar mass of citric acid = 192.2 g/mole a)What is the molarity(M)of citric acid(H3A)in lemon ...
Sunday, December 14, 2014 at 11:46pm

chemistry
A 27.00mL sample of an H2SO4 solution of unknown concentration is titrated with a 0.1422M KOH solution. A volume of 40.22mL of KOH was required to reach the equivalence point. What is the concentration of the unknown H2SO4 solution? Any help would be greatly appreciated. (:
Sunday, December 14, 2014 at 11:36pm

Chemistry
Why is it hard to use the periodic table to predict the oxidation #'s of the transition elements?
Sunday, December 14, 2014 at 11:32pm

chemistry
Which of the following is an example of quantization? A. The amount of time spent in a classroom B. The number of students in a classroom C. Learning happening in a classroom D. The temperature range in a classroom I strongly believe the answer is A. Any objections.
Sunday, December 14, 2014 at 7:59pm

Chemistry
If 25.00 ml of H2SO4 solution is titrated to an end point with 32.16 ml of 0.1986 M NaOH, what is the molarity(M) of the H2SO4 acid?
Sunday, December 14, 2014 at 7:24pm

Chemistry
25.0 ml of 0.235 M NiCl2 are combined with 30.0 ml of 2.260 M KOH. How many grams of nickel hydroxide will precipitate?
Sunday, December 14, 2014 at 5:28pm

Chemistry
A gas is allowed to expand at constant temperature from 4.274L to 6.877L against an external pressure of 1.977 atm. If at the same time the gas absorbs 773 J of heat from the surroundings, what is Delta E for this process? (Note: Pay attention to units; 1 L atm = 101.325 J) I ...
Sunday, December 14, 2014 at 3:24pm

basic chemistry
Fe3O4 + 4 H2 -> 3 Fe + 4 H2O What mass (g) of Fe3O4 would be needed to react with 1.38 x 10^3 mol H2?
Sunday, December 14, 2014 at 3:12pm

Chemistry
What is the conjugate acid of HPO4^2-(aq)? A. H3PO4(aq) B. HPO4^2-(aq) C. H2PO4-(aq) D. PO4^3-(aq) E. H3O+(aq)
Sunday, December 14, 2014 at 2:56pm

chemistry
How many moles of iron are expected from the reaction between 115 moles of H2 with excess Fe3O4?
Sunday, December 14, 2014 at 2:19pm

chemistry
does an atom of an element have similar chemical properties with an ion of the same element?
Sunday, December 14, 2014 at 2:16pm

chemistry
Magnesium has three naturally occurring isotopes: Mg-24 with mass 24.3050 amu and a natural abundance of 78.99 %, Mg-25 with mass 24.9858 amu and a natural abundance of 10.00 %, and Mg-26 with mass 25.9826 amu and a natural abundance of 11.01 %. Calculate the atomic mass of ...
Sunday, December 14, 2014 at 2:28am

Chemistry
Which of the following factors affect the solubitity? a)temperature of the solutions b)polarity of the solvent vs solute molecules c)partial pressure of the gas above the solution d) all of the above
Sunday, December 14, 2014 at 12:54am

chemistry
Iodine(I2)is a solid molecular compound at room temperature. Predict its solubility in liquid water(H2O)and in liquid cyclohexane(C6H12) at room temperature respectively and provide explain for your answer.
Sunday, December 14, 2014 at 12:18am

chemistry
The solubility of NaCl at 17 celsisus degrees is 39 g per 100 ml water. If 83 g of NaCl is dissolved in 250ml of water at the same temperature, the resulting solution is: a)unsaturated; b)saturated; c)supersaturated
Saturday, December 13, 2014 at 11:39pm

Chemistry
Consider the thermal decomposition of potassium chlorate. 2 KClO3 (s)-----> 2 KCl (s) + 3 O2 (g) A mixture containing KCl and KClO3 weighing 1.80 g was heated producing 1.40 x 102 mL of O2 gas at STP. What percent of the original mixture was KClO3? Is this how I should ...
Saturday, December 13, 2014 at 9:02pm

chemistry
How much energy (in kilojoules) is needed to heat 4.00g of ice from -11.0∘C to 21.5∘C? The heat of fusion of water is 6.01kJ/mol, and the molar heat capacity is 36.6 J/(K⋅mol) for ice and 75.3 J/(K⋅mol) for liquid water.
Saturday, December 13, 2014 at 7:20pm

chemistry
Suppose 100 mL of NO at STP is mixed with 400 mL of O2 at STP. 2 NO (g) + O2 (g)---> 2 NO2 (g) After the reaction goes to completion, what is the partial pressure of NO2 in the resulting mixture of gases at STP? I know the relation between pressure and volume is P1V1=P2V2, ...
Saturday, December 13, 2014 at 2:38pm

chemistry
What is periodicity.
Saturday, December 13, 2014 at 2:09pm

Chemistry
how many milliliters of 4 M h2so4 are needed to react completely with 23.7g of Bao2
Saturday, December 13, 2014 at 9:52am

chemistry
Which term has the same numerical value for the forward reaction as it has for the reverse reaction, but with opposite sign? a. ^E ( delta E) b. Ea1 c. Ea’ d. Ea2
Saturday, December 13, 2014 at 4:58am

Chemistry
How much of a 5.2M sucrose solution should you use to make 81.0mL of a 0.040M solution?
Saturday, December 13, 2014 at 1:11am

Chemistry
Are there any structural isomers of hydrocarbons from methane to decane have 3 stereogenic C atoms? (i know that there are none for decane itself, but I am wondering about the others before it.) Thanks in advance!
Saturday, December 13, 2014 at 12:44am

Chemistry
Red light has a wavelength of 700 nm and a frequency of 4.3 x 1014 s-1. What is the energy of a single photon of red light? A. 2.85 x 10-34 J B. 2.85 x 1019 J C. 2.85 x 10-20 J D. 2.85 x 10-19 J
Friday, December 12, 2014 at 10:45pm

chemistry
In which unit is the wavelength of an electromagnetic wave commonly measured? A. J B. nm C. s–1 D. kg All most positive it is b but I just wanted to make sure.
Friday, December 12, 2014 at 10:34pm

Chemistry
What does the photoelectric effect show about the connection between light and electrons? A. Light can remove electrons from atoms. B. Electrons are composed of light. C. Light is composed of electrons. D. It takes 2 photons of light to cause 1 electron to begin flowing.
Friday, December 12, 2014 at 8:58pm

chemistry
what mass of water is necessary to prepare 150.0g of 1.30% saline solution
Friday, December 12, 2014 at 5:03pm

chemistry
What mass of solution contains 15.0g of sulfuric acid in a 20.0% solution
Friday, December 12, 2014 at 5:02pm

Chemistry
14.6 mL of hydrochloric acid is completely neutralized by 25.0 mL of 1.40 M sodium hydroxide, what was the hydrochloric acid mass percent (m/m) before the titration? (Density of hydrochloric acid is 1.02 g/cm3)
Friday, December 12, 2014 at 3:08pm

Chemistry
Acetylene gas, C2H2, reacts with oxygen according to the following equation. If 46.0 g of acetylene reacts with 100.0 g of oxygen, what is the theoretical yield of heat produced from the reaction? ___ C2H2(g) + ___ O2(g) → ___ CO2(g) + ___ H2O(g); balanced reaction ...
Friday, December 12, 2014 at 3:04pm

Chemistry
The mass/volume percent of a sodium sulfate and water solution is 12.0% m/v. If the density of the solution 1.22 g/mL, what is the molarity of the solution?
Friday, December 12, 2014 at 2:58pm

chemistry
A sodium atom when excited gives off two very specific wavelengths of visible light. What does this tell us about sodium? A. There are two principal electron transitions in sodium. B. There are two electrons in a sodium atom. C. A sodium atom has its electrons in two energy ...
Friday, December 12, 2014 at 2:40pm

Chemistry
A spoon of sterling silver is 92.5% silver by mass and the rest is made of other metals, usually copper. If the spoon contains 0.557 mol of silver, what is the mass of the spoon?
Friday, December 12, 2014 at 12:15pm

Chemistry
My teacher gave us a packet with many questiona on it for homework. I was able to figure all 44 questions except the following 2.... Help!?!?! 9. "In order to have 1.00 mole of gas fit in a box that measures 1.30 dm x 2.40 dm x 5.83 dm at 1.00 atm, what must the ...
Friday, December 12, 2014 at 9:05am

Chemistry
A gas occupies 21.0 L at 2.00 atm pressure and 27oC. Calculate its volume at STP.
Friday, December 12, 2014 at 6:19am

Chemistry
0.250 moles of HCL and 0.100 moles of acetic acid are mixed in 0.365 moles of water. Determine the following: [CH3COOH], [CH3COO^-], pH and pOH. Ka=1.8E-5. Calculate the pH of 0.05M CH3COO-Na+ . Plz show me step by step, really confused right now.
Friday, December 12, 2014 at 4:55am

Chemistry
If NaCl has a solubility of 36.0 g in 100 g of H2O at 20 °C, how many moles of water are needed to prepare a saturated solution containing 0.263 mol of NaCl at 20 °C?
Friday, December 12, 2014 at 1:39am

Chemistry
How many milliliters of 0.150M BaCl2 are needed to react completely with 40.0mL of 0.260M Na2SO4?
Friday, December 12, 2014 at 12:43am

chemistry
Calculate the amount of heat required to heat a 4.0kg gold bar from 20∘C to 61∘C. Specific heat capacity of gold is 0.128 J/g∘C. How do we figure this out?
Friday, December 12, 2014 at 12:36am

chemistry
What is the molality of 67.1g of Nano3 in 2.5l of water i get the molar mass of nano3 and divide it by the 67.1g and multipy it by 2.5l
Friday, December 12, 2014 at 12:35am

chemistry
What is the difference between the ionization energy of inner-shell electrons and the ionization energy of outer-shell electrons? A. The ionization energy of inner-shell electrons is less than the ionization energy of outer-shell electrons. B. They are equal to each other. C. ...
Friday, December 12, 2014 at 12:13am

Chemistry
Which of the following is an example of quantization? A. The amount of time spent in a classroom B. The number of students in a classroom C. Learning happening in a classroom D. The temperature range in a classroom What is the definition of quantization
Friday, December 12, 2014 at 12:12am

chemistry
When calcium chloride and ammonium phosphate are mixed, an insoluble precipitate of calcium phosphate forms and falls out of solution. After careful analysis of the purified precipitate, 8.16 * 10^25 atoms of calcium are found in the solid. How many other atoms are in the ...
Thursday, December 11, 2014 at 11:17pm

chemistry
Which statement describes the principal quantum number (n)? A. The quantum number that indicates the subshell occupied by an electron B. The quantum number that indicates the energy level of the electron C. A subdivision of an energy level in an atom D. The probability of ...
Thursday, December 11, 2014 at 11:13pm

chemistry
What does the fact that a blackbody can absorb light only in specific-sized "packets" say about light? A. It has no mass. B. It is composed of electrons. C. It is composed of atoms. D. It is quantized. I have no idea what the answer is
Thursday, December 11, 2014 at 10:57pm

chemistry
calculate the energy required to raise the temp of 72g of water from 50c tp 150
Thursday, December 11, 2014 at 10:57pm

Chemistry
Hydrogen chloride gas can be prepared by the following reaction: 2NaCl(s) + H2SO4(aq) --> 2HCl(g) + Na2SO4(s) How many grams of HCl can be prepared from 2.00 mol H2SO4 and 2.56 mol NaCl?
Thursday, December 11, 2014 at 10:48pm

Chemistry
Hydrogen chloride gas can be prepared by the following reaction: 2NaCl(s) + H2SO4(aq) --> 2HCl(g) + Na2SO4(s) How many grams of HCl can be prepared from 2.00 mol H2SO4 and 2.56 mol NaCl?
Thursday, December 11, 2014 at 10:48pm

Chemistry
1. Calculate the concentration of H3O+, HC2O4-1, and oxalate ion (C2O42-) in a 0.175 M solution of oxalic acid (C2H2O4). [For oxalic acid, Ka1 = 6.5 ´ 10-2, Ka2 = 6.1 ´ 10-5.]
Thursday, December 11, 2014 at 10:43pm

Chemistry
All electromagnetic energy (light), including gamma rays through radio waves, has what in common? A. Speed B. Wavelength C. Frequency D. Energy E. Amplitude I think a
Thursday, December 11, 2014 at 10:42pm

chemistry
is finding the molality and molarity the same concept
Thursday, December 11, 2014 at 10:37pm

chemistry
What does electron affinity depend on? A. Both the effective nuclear charge and the number of shells in the atom containing electrons B. Attraction between the protons and neutrons C. Only the effective nuclear charge D. Attraction between the valence electrons and core ...
Thursday, December 11, 2014 at 10:30pm

Chemistry
Core electrons shield what from the pull of the nucleus? A. Identical electrons B. Valence electrons C. Neutrons D. Protons I was thinking d or a.
Thursday, December 11, 2014 at 10:26pm

chemistry
how much heat is required to raise a 54g sample of water from -20 celsius to 90 celsius explain
Thursday, December 11, 2014 at 10:22pm

chemistry
How do u tell of a solute is polor or non polar based on what
Thursday, December 11, 2014 at 9:43pm

chemistry
how many moles of solute are contained in 18.5ml 2.5m CaCL2
Thursday, December 11, 2014 at 9:22pm

chemistry
What is the molality of 67.1g of Nano3 in 2.5l of water
Thursday, December 11, 2014 at 8:51pm

chemistry
how wud u prepare 1L of a 1.30M aqueous solution of barium sulfide explain
Thursday, December 11, 2014 at 8:48pm

chemistry
how much heat has been absorbed by 2500g of water when its temperature changes from 23c to 27c PLEASE EXPLAin
Thursday, December 11, 2014 at 8:47pm

chemistry
What is the ppm of 4.50mg of ddt in 10kg of seal fat?
Thursday, December 11, 2014 at 8:45pm

chemistry
Increasing pressure does what to solubility. Increasing surface area? increasing temp?
Thursday, December 11, 2014 at 8:44pm

Chemistry
I am doing a lab and broke my glass beaker. Is it of to put 0.1 M hydrochloric acid in a plastic beaker?
Thursday, December 11, 2014 at 6:10pm

Chemistry
Methane reacts with oxygen to produce carbon dioxide, water and heat. If the percent yield of the reaction is 90.0%, how many grams of methane must be burned to produce 150.0 kJ of energy? ___ CH4 (g)+ ___ O2 (g) → ___ CO2 (g) + ___ H2O(g) + 802 kJ
Thursday, December 11, 2014 at 5:04pm

Chemistry, Vapor Pressure
Select the pair of substances in which the one with the higher vapor pressure at a given temperature is listed first. 1. C7H16, C5H12 2. CCl4, CBr4 3. H2O, H2S 4. CH3CH2OH, CH3-O-CH3 5. Xe, Kr
Thursday, December 11, 2014 at 4:29pm

Chemistry
After adding a hot piece of titanium to a cup containing 300.0 mL of 30.0 °C water, the final temperature of the solution is 41.2 °C and the final volume of the solution is 400.0 mL. The density of titanium is 4.50 g/cm3. If no energy is lost to the surroundings, what ...
Thursday, December 11, 2014 at 3:13pm

chemistry
The ?H of the reaction below is -575.13 kJ. Is this reaction spontaneous? 2ZnS + 3O2 + C ? 2SO2 + 2Zn + CO2 A. It is not because the ?H of the reaction is negative. C. It depends on the temperature because the ?H of the reaction is negative and the ?S is negative. D. It ...
Thursday, December 11, 2014 at 3:07pm

chemistry
When 3.2 g of ammonium chloride is dissolved in 75 g of water, the temperature of the solution decreases from 22.8°C to 20.1°C. What is the energy of dissolution of NH4Cl per mole? (The molecular mass of NH4Cl = 53.49 g/mol, and the specific heat of water = 4.18 J/g&...
Thursday, December 11, 2014 at 2:12pm

Chemistry
Calculate the freezing and boiling points of a solution containing 14.9g FeCl3 in 176g water.
Thursday, December 11, 2014 at 12:23pm

chemistry
isotope chromium -51 has a half life of 28 days. If the original sample had a mass of 28.0 grams, what mass of chromium -51 sample remains after 84 days?
Thursday, December 11, 2014 at 10:31am

chemistry
write an equation that describes the equilibrium present in a saturated solution of Cu3(PO4)2 someone please explain to me, thanks!
Thursday, December 11, 2014 at 5:53am

chemistry
A solution contains 0.20 M Cl- and 0.20 M SO4^2-. a) identify a cation that could be added to the solution to give a precipitate with only one of these anions. MY answer: Cu+ b) write the net ionic equation for the precipitation reaction in part a) MY answer: Cl^- + Cu^+ ==>...
Thursday, December 11, 2014 at 5:51am

chemistry
Q) in the reaction, 210kj of heart energy is used to form 3.0 miles of hydrogen. Calculate how much heat energy is needed to make 1000kg of hydrogen.
Thursday, December 11, 2014 at 2:28am

Chemistry
Benzene, C6H6, consists of six member ring of sp2 hybridized p orbital. How many (pi)_2p bonding, anti bonding, and nonbonding molecular orbitals exist for benzene?
Thursday, December 11, 2014 at 12:21am

Chemistry
Calculate the percent purity of a sample of zinc metal if 325 mL of hydrogen gas is collected by water displacement at a temperature of 22.0 C and an atmospheric pressure of 745.0 mm Hg when 1.12 g of the sample is reacted with excess HCl: Zn + 2 HCl = H2 + ZnCl2. The vapor ...
Thursday, December 11, 2014 at 12:10am

Chemistry
When 3.2 g of ammonium chloride is dissolved in 75 g of water, the temperature of the solution decreases from 22.8°C to 20.1°C. What is the energy of dissolution of NH4Cl per mole? (The molecular mass of NH4Cl = 53.49 g/mol, and the specific heat of water = 4.18 J/g&...
Wednesday, December 10, 2014 at 10:52pm

Chemistry
How many molecules are in 0.923 mol of selenium tetrabromide?
Wednesday, December 10, 2014 at 8:08pm

Urgent chemistry help
is there anything unusual about how the first elements are named when naming the compound? Is there anything unusual about how the second element is named when naming the compound? Why are the elements in the binary compounds combined in different ratios ( as shown by the ...
Wednesday, December 10, 2014 at 7:39pm

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