Saturday
August 30, 2014

Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

Post a New Question | Current Questions

Chemistry
Assume a baker of pure water has been boiling for 30 minutes. What is in the bubbles in the boiling water? Answer: water vapor. WHY?
Friday, January 17, 2014 at 3:05pm

Chemistry
Heat is given off when hydrogen burns in air according to the equation: 2H2 + O2 ---> 2H2) What is responsible for the heat? I know the answer is froming hydrogen-oxygen bonds gives off energy, but why?
Friday, January 17, 2014 at 3:00pm

Chemistry
Iron combines with oxygen and water from the air to form rust. If an iron nail were allowed to rust completely, one should find that the rust weighs: I know the answer is the rust should way more than the nail it came from but can someone explain why please!
Friday, January 17, 2014 at 2:44pm

chemistry
How many moles of protons are present in 7.54 grams of Rubidium? Report your answer to 3 significant figures.
Friday, January 17, 2014 at 1:32pm

Chemistry
If you add 4.6 g of sodium to water, how many molecules of H2 will be formed? (4points) 2Na(s)+2H2O(l)-->2NaOH(aq)+H2(g)
Friday, January 17, 2014 at 11:34am

Chemistry Check Please! ?Fixed
A solution is prepared by dissolving 3.44 g of sucrose, C12H22O11, in 118 g of water. a) What is the molality of the resulting solution? b) What is the mole fraction of water in this solution? B) moles of h2o=118g/18(g/mol)=6.548 mol moles of c12h22O11= 3.44g/342.3(g/mol)=0....
Friday, January 17, 2014 at 2:52am

chemistry
how many grams of CH4 (methane) must be burned to form 82.6g of H2O? equation: CH4+O2----> CO2+H2O
Thursday, January 16, 2014 at 11:33pm

chemistry
how many grams of CH4 (methane) must be burned to form 82.6g of H2O? equation: CH4+O2----> CO2+H2O
Thursday, January 16, 2014 at 9:13pm

chemistry
A sulfuric acid solution containing 571.8gg of H2SO4 per liter of solution has a density of 1.329 g/cm3 Calculate the mole fraction of H2SO4 in this solution.
Thursday, January 16, 2014 at 5:26pm

chemistry
The best means of personal protection from radiation for emergency responders is the implementation of three basic principles: time, distance and shielding. Please show your work when answering the following questions: a. Using the inverse square law of radiation, what Geiger ...
Thursday, January 16, 2014 at 4:53pm

chemistry
A student finds a rock on the way to school. In the laboratory he determines that the volume of the rock is 29.7 cm3, and the mass in 139.943 g. What is the density of the rock?
Thursday, January 16, 2014 at 9:41am

Chemistry Check Please!
A solution is prepared by dissolving 3.44 g of sucrose, C12H22O11, in 118 g of water. a) What is the molality of the resulting solution? b) What is the mole fraction of water in this solution? B) moles of h2o=118g/18(g/mol)=6.5556 mol moles of c12h22O11= 3.44g/342.3(g/mol)=0....
Thursday, January 16, 2014 at 1:19am

Chemistry
When a student doesn't polish a sample of Mg ribbon before massing it, what happens when calculating the molar volume? Is it that the Mg ribbon doesn't completely react therefore less volumes of gas are produced?
Wednesday, January 15, 2014 at 11:58pm

Chemistry
Calculate (in calories) the amount of heat needed to melt 96g of ice at -24 degrees C to water at 28 degrees C.
Wednesday, January 15, 2014 at 8:23pm

Chemistry
A weightlifter manages to lift a 133 kg (that's 293 pounds, which sounds much more impressive) weight a distance of 1.4 m. How many kcal of heat energy is equivalent to this lift?
Wednesday, January 15, 2014 at 6:01pm

Chemistry
A certain substance has a heat of vaporization of 26.49 kJ/mol. At what Kelvin temperature will the vapor pressure be 5.00 times higher than it was at 285 K?
Wednesday, January 15, 2014 at 1:49pm

Chemistry
1. Calculate the decrease in temperature when 6.00 L at 20.0 °C is compressed to 4.00 L. 2. A container containing 5.00 L of a gas is collected at 100 K and then allowed to expand to 20.0 L. What must the new temperature be in order to maintain the same pressure (as ...
Wednesday, January 15, 2014 at 4:01am

Chemistry
1. If 22.5 L of nitrogen at 748 mm Hg are compressed to 725 mm Hg at constant temperature. What is the new volume? 2. A gas with a volume of 4.0L at a pressure of 205kPa is allowed to expand to a volume of 12.0L. What is the pressure in the container if the temperature remains...
Wednesday, January 15, 2014 at 3:55am

Chemistry
What is the uncertainty of the concentration...0.00001? Please explain how ... Would the uncertainty be the same or different for 0.01?
Tuesday, January 14, 2014 at 11:32pm

Chemistry
What is uncertainty and how can I calculate it ? For example, 0.001 +/- ?
Tuesday, January 14, 2014 at 11:26pm

Chemistry (My previous post lacked something)
Question: At STP propane (C3H8) burns in oxygen to form 2.15L of carbon dioxide and water. The question is in 4 parts. I just need the first: a)What mass of oxygen is necessary for this reaction? So far I've got 2.15 L x 1 mole /22.4 L But when I try to do the mole ratio, ...
Tuesday, January 14, 2014 at 11:10pm

Chemistry
So I have the balanced equation: c3H8 +502 = 3C02 +4H20 Question: At STP propane (C3H8) burns in oxygen to form 2.15L of carbon dioxide and water. So I've got 2.15 L x 1 mole /22.4 L But when I try to do the mole ratio, I don't know what to do since the 2.15 L is of ...
Tuesday, January 14, 2014 at 10:42pm

Chemistry
When the oxide of generic metal M is heated at 25.0 °C, only a negligible amount of M is produced. O2M(s) ----> M(s) +O2(g) delta G= 290.5 Kj/mol When this reaction is coupled to the conversion of graphite to carbon dioxide, it becomes spontaneous. What is the chemical ...
Tuesday, January 14, 2014 at 10:25pm

Chemistry
How might fragrance designers benefit from an understanding of how the shape of an odorant stimuilates a receptor? PLEASE!!! I'm completeing another C^3 assignment and its due tomorrow so i could really use the help!
Monday, January 13, 2014 at 11:49pm

CHEMISTRY
HOW CAN I WRITE UNCERTAINTY FOR CONCENTRATION? EXAMPLE: 0.0001 M +/- ? PLEASE EXPLAIN WHY....AND IS IT DIFFERENT FOR EACH CONCENTRATION? THAT IS WHAT ABOUT 0.00001 M? 0.01M?
Monday, January 13, 2014 at 11:34pm

Chemistry
What mass of AgN03 would you dissolve in water to get 1g of silver?
Monday, January 13, 2014 at 8:48pm

chemistry
You are tasked with preparing a 500mL nutrient solution containing 5mg/L of phosphorous (P), 3mg/L nitrate (NO3 -) and 100 mg/L chloride (Cl-). To make this solution, you have powdered sodium chloride, a 100 mg/L solution of phosphorus, a 1000 mg/L of sodium nitrate (NaNO3) ...
Monday, January 13, 2014 at 4:57pm

analytical chemistry
What are the advantages of using graphical endpoint(potentiometric endpoint) compared to usual endpoint(chemical indicator)
Monday, January 13, 2014 at 12:10pm

Chemistry Damon step bystep for me
A 0.887g sample of a mixture of nacl and kcl is dissolved in water and the solution is treated with an excess of agn03 producing 1.822g of agcl. What is the percent by mas of each compound in the mixture My calculation 1.822g/143g/mol = 0.013M x/58 + y/74 (0.887g-x) = 0.013M I...
Sunday, January 12, 2014 at 4:28pm

Chemistry
Draw condensed structural formula for... 2,3-dichloropropanoic acid I know it is hard to DRAW online, but still you can do something like this... CH-...
Sunday, January 12, 2014 at 2:52pm

Chemistry
Draw condensed structural formula for... 2,3-dichloropropanoic acid
Sunday, January 12, 2014 at 2:49pm

Chemistry Damon step by step for me
you are given a solid that is a mixture of na2s04 and k2s04. A 0.215g sample of the mixture is dissolved in water. An excess of an aqueous solution of bacl2 is added. The bas04 that is formed is filtered, dried and weighed. Its mass is 0.299g. What mass of s04 ion is in the ...
Sunday, January 12, 2014 at 2:42pm

Chemistry Damon
1g of mixture of na2c03 and k2c03 was made upto 250ml is aqueous solution . 25ml of this solution was neutralized 20ml of hcl of unknow concentration. The neutralized solution required 16.24ml of 0.1N AGN03 for precipitation. Calculate a) the k2c03 is mixture b) conc of hcl in...
Sunday, January 12, 2014 at 1:04pm

chemistry Damon helps me step by step
1g of mixture na2c03 and k2c03 was mole made upto 250ml is aqueous solution. 25ml of this solution was neutralized. 20ml of hcl of unknown concentration. The neutralized solution required 16.24ml of 0.1N AGNo3 for precipitation, Calculate a) the % k2c03 is mixture b) conc of ...
Sunday, January 12, 2014 at 11:43am

Chemistry
Which method(High Performance Liquid Chromatography or Gas Liquid Chromatography) would be suitable for the separation of the following mixtures? 1) Mixture of paracetamol, codeine and caffeine. 2) Mixture of alpha-pinene, beta-pinene, eucalyptol, alpha-terpineol. Please ...
Sunday, January 12, 2014 at 12:33am

Chemistry
Draw condensed structural formula for... 2,3-dichloropropanoic acid
Sunday, January 12, 2014 at 12:30am

Chemistry
25g of a sample of ferrous sulphate was dissolved in water containing dilute h2s04 and the volume made up to one litre. 25ml of this solution required 20ml of N/10 kmn04 solution for complete oxidation. Calculate the percentage of f2s04 7h20 in the sample 1 g of mixture of ...
Saturday, January 11, 2014 at 11:48pm

Chemistry
How is the high performance liquid chromatography column designed to ensure greater efficiency?
Saturday, January 11, 2014 at 11:19pm

Chemistry
Draw condensed structural formula for... 2,3-dichloropropanoic acid
Saturday, January 11, 2014 at 11:15pm

chemistry who helps me step by step
25g of a sample of ferrous sulphate was dissolved in water containing dilute h2s04 and the volume made up to one litre. 25ml of this solution required 20ml of N/10 kmn04 solution for complete oxidation. calculate the percentage of fe204 7h20 in the sample. My calculation 0.02x...
Saturday, January 11, 2014 at 8:10pm

Chemistry
Assuming that seawater has a total ion concentration (aka colligative molarity) of 1.10 M conc, calculate how many liters of seawater are needed to produce 68.7 L of fresh water at 20 C with an applied pressure of 51.0 bar.
Saturday, January 11, 2014 at 2:19pm

Chemistry
What would be the temperature change if 3.0g of water absorbed 15J of heat?
Saturday, January 11, 2014 at 2:04pm

Chemistry
How can reaction intermediates in an organic synthesis be separated and recovered using thin layer chromatography?
Saturday, January 11, 2014 at 9:39am

Chemistry
Consider the reaction 2 Al2O3(s) → 4 Al(s) + 3 O2(g). ∆H = +3339.6 kJ/mol What is the change in heat when 0.455 L of a 3.60 M Al solution reacts with excess O2 ?
Friday, January 10, 2014 at 5:58pm

chemistry
Automotive air bags inflate when sodium azide, NaN3, rapidly decomposes to its component elements: 2NaN3(s)→2Na(s)+3N2(g) a)How many moles of N2 are produced by the decomposition of 1.60mol of NaN3? b)How many grams of NaN3 are required to form 14.0g of nitrogen gas? c)...
Friday, January 10, 2014 at 5:10pm

Chemistry
How would you define pressure in the unit of thermodynamics? Is it just a force basically?
Friday, January 10, 2014 at 12:21am

AP Chemistry
The ionic substance T3U2 ionizes to form T2+ and U3− ions. The solubility of T3U2 is 4.07×10−20 mol/L. What is the value of the solubility-product constant?
Thursday, January 9, 2014 at 5:56pm

AP Chemistry
What is the value of Ksp for Ag2SO4 if 5.70 g is soluble in 1.00 L of water?
Thursday, January 9, 2014 at 5:47pm

Chemistry/Math
The density of water is 1 g/cm^3. What is the mass of 7.500 liters of water reported in kilograms? I got 7.5kg. Is this correct?
Wednesday, January 8, 2014 at 9:32pm

chemistry
Please explain, in simple English, why is milk a colloid?
Wednesday, January 8, 2014 at 7:30pm

AP Chemistry
Calculate the solubility product constant for calcium carbonate, given that it has a solubility of 5.3×10^7 g/L of water.
Wednesday, January 8, 2014 at 6:19pm

AP Chemistry
A solution of AgI contains 1.2 mol/L Ag+. Ksp of AgI is 8.3×10^17. What is the maximum I− concentration that can exist in this solution? Answer in units of mol/L
Wednesday, January 8, 2014 at 6:17pm

AP Chemistry
Calculate the concentration of Hg2+ ions in a saturated solution of HgS(s). (Ksp=1.7×10^52) Answer in units of mol/L What volume of solution contains one Hg2+ ion? Answer in units of L/ion
Wednesday, January 8, 2014 at 6:14pm

chemistry
1. describe in outline a suitable procedure for the preparation of saturated solution of sodium nitrate at 30 degree celsius 2. State 2 techniques that can be used to recover crystals of the sodium nitrate from its saturated solution
Wednesday, January 8, 2014 at 8:40am

Chemistry
139 g of water at 4.9 degrees Celsius mixed with 241 g of water at 96.0 degrees Celsius (Tf=62.7)
Wednesday, January 8, 2014 at 1:04am

Chemistry
139 g of water at 4.9 degrees Celsius mixed with 241 g of water at 96.0 degrees Celsius (Tf=62.7)
Wednesday, January 8, 2014 at 1:03am

Chemistry
How do I write a blog for my chemistry project?
Tuesday, January 7, 2014 at 9:08pm

chemistry
A ternary ionic compound consists of a monoatomic ion plus a cation? true or false.
Tuesday, January 7, 2014 at 9:21am

Chemistry
The answeres to the previous post was not what I am looking for...so please try to help me..... How can I make various concentrations of CuSO4(this is a blue solution)? I know that to make 0.1M you would fill the copper solution up to 10mL in the graduated cylinder and then ...
Monday, January 6, 2014 at 10:34pm

CHEMISTRY
The answeres to the previous post was not what I am looking for...so please try to help me..... How can I make various concentrations of CuSO4(this is a blue solution)? I know that to make 0.1M you would fill the copper solution up to 10mL in the graduated cylinder and then ...
Monday, January 6, 2014 at 8:55pm

Chemistry
The answeres to the previous post was not what I am looking for...so please try to help me..... How can I make various concentrations of CuSO4(this is a blue solution)? I know that to make 0.1M you would fill the copper solution up to 10mL in the graduated cylinder and then ...
Monday, January 6, 2014 at 7:34pm

Chemistry
How can I make various concentrations of CuSO4? I know that to make 0.1M you would fill the copper solution up to 10mL in the graduated cylinder and then add water to the rest..but how can you prepare a 0.01M? 0.001? 0.0001?..........using water and graduated cylinder?
Monday, January 6, 2014 at 7:05pm

Chemistry
How do you express relative amounts pf each element in a compound?
Monday, January 6, 2014 at 6:56pm

chemistry
1- A compound is 87.5% nitrogen and 12.5% hydrogen. The molecular weight of the compound is 32 g/mol. Describe the molecule referencing shape, and inter-molecular forces. 2- Gaseous butadiene, C4H6 , reacts with hydrogen gas in the presence of a platinum catalyst to form ...
Monday, January 6, 2014 at 5:56pm

chemistry
Consider the following reaction: CH3X + Y  CH3Y + X At 25oC, the following two experiments were run, yielding the following data: Experiment 1 : [Y]0 = 3.0 M [CH3X] Time(hr) 7.08 x 10-3M 1.0 4.52 x 10-3M 1.5 2.23 x 10-3M 2.3 4.76 x 10-4M 4.0 8.44 x 10-5M 5.7 2.75 x 10-...
Monday, January 6, 2014 at 5:56pm

chemistry
Acetic acid (CH3CO2H) is a weak acid. As a result, a solution of sodium acetate (NaCH3CO2) will be _____.
Monday, January 6, 2014 at 7:32am

Grade 12 Chemistry
Caprytic acid, also called octanoic acid, is an 8-carbon fatty acid that is used as a sanitizer on dairy equipment that comes in contact with milk.The acid has a molar mass of 144.21 g/mol. An aqueous solution of the sanitizer containing 12.25 g/L has a pH of 2.98. What is the...
Sunday, January 5, 2014 at 6:53pm

Chemistry
Caprytic acid, also called octanoic acid, is an 8-carbon fatty acid that is used as a sanitizer on dairy equipment that comes in contact with milk. The acid has a molar mass of 144.21 g/mol. An aqueous solution of the sanitizer containing 12.25 g/L has a pH of 2.98. What is ...
Sunday, January 5, 2014 at 2:50pm

Grade 12 Chemistry
This is my question: AspirinTM (acetylsalicylic acid) is a monoprotic acid with molar mass of 180g/mol. An aqueous solution containing 3.3 g/L has a pH of 2.62. What percentage of acetylsalicylic acid molecules ionizes in the solution?
Sunday, January 5, 2014 at 12:40pm

chemistry Damon check my calculation
25g of a sample of ferrous sulphate was dissolved in water containing dilute h2s04 and the volume made up to one litre. 25ml of this solution required 20ml of this solution required 20ml of n/10 kmn04 solution for complete oxidation. Calculate the percentage of f2s047h20 in ...
Saturday, January 4, 2014 at 9:43pm

chemistry
a 350ml buffer solution is .150M in HF and .150M in NAF. What mass of naoh could this buffer neutralize before ph rises above 4.0? So far I got .285714 from 10^-.544. After that I tried to do .285714(x/.0525-x) but this doesn't worl. The answer is 1.2g. Help, please?
Saturday, January 4, 2014 at 4:13pm

Chemistry
A sample of NH3 gas occupies 75.0 liters at STP. How many molecules is this?
Friday, January 3, 2014 at 5:05pm

chemistry
write the british standard related to following details 1. A plain carbon steel with a composition of 0.46% of carbon and 1.5% of manganese. the steel is supplied to a harden ability specification
Friday, January 3, 2014 at 1:07am

chemistry
Calculate the uncertainty in speed of an electron if its position in space is known within the range of ±2pm. Assume me = 9×(10^-31) kg
Thursday, January 2, 2014 at 6:58am

Chemistry
What is the relationship between temperature and the equilibrium constant k? Is it a direct or indirect relationship? And why?
Wednesday, January 1, 2014 at 11:54pm

Chemistry
Equimolar amounts of gas A and B, each at an initial partial pressure of 1.00 atm are combined in a flask. The flask is sealed and allowed to react to completion according to the reaction: 2A(g)+ B(g) --> C(g) What is the final pressure inside the flask?
Wednesday, January 1, 2014 at 11:08pm

chemistry
The kinetic theory of gases is based on a number postulates from which the equation P= 1/3× N/V×m×µ² is derived (P is the pressure of the gas, N the number of molecules in the container, m the mass of each molecule and µ² is the mean ...
Wednesday, January 1, 2014 at 9:20pm

Chemistry
What is the effect of Independent Variable on Dependent Variable ?
Monday, December 30, 2013 at 6:01pm

Chemistry
What is the effect of Independent Variable on Dependent Variable ?
Monday, December 30, 2013 at 5:53pm

analytical chemistry
Regarding ICP analysis 4. For each of the following electrical discharge sources list the major strengths and limitations: a. dc arcs, b. ac arcs, c. ac sparks.
Friday, December 27, 2013 at 8:08am

chemistry
Where is an electron in 3Py orbital most likely to be found and where does the probability it vanish?
Thursday, December 26, 2013 at 9:19am

chemistry
The kinetic theory of gases is based on a number postulates from which the equation P= 1/3× N/V×m×µ² is derived (P is the pressure of the gas, N the number of molecules in the container, m the mass of each molecule and µ² is the mean ...
Thursday, December 26, 2013 at 7:55am

chemistry
copper,stone,wood&ice what property they gives?
Wednesday, December 25, 2013 at 1:05pm

chemistry
Please post any helpful links(tutorials) and practice worksheets for naming alkanes,alkenes, and alkyns.
Monday, December 23, 2013 at 2:14pm

chemistry
what current will be able to produce 20 volume of chlorine by electrolysis at STP within one hour?
Sunday, December 22, 2013 at 6:57am

Chemistry
I am struggling in naming alkanes,alkenes,... How do you determine the parent chain? I know it is the longest chain,but there are structures that look quite complicated....the branched ones are counted...!!!! I am so confused on determining the correct parent chain!!!!!! ...
Saturday, December 21, 2013 at 8:14pm

chemistry
Estimate the surface energy of (110) face of K crystals given just the information in the periodic table. Express your answer in the unit of J/cm2.
Saturday, December 21, 2013 at 10:08am

chemistry
Polyglycolic acid, PGA, is a polymer that we know rather well how to control the structure of (even though there are currently only limited applications). So in the lab we have created two types of PGA for testing, a linear chain PGA and a branched chain PGA. Assume comparable...
Saturday, December 21, 2013 at 10:08am

chemistry
Lead iodide, PbI2, has a Ksp in water of 7.1e-9 M3 at room temperature. Calculate the solubility of PbI2 in water. Express your answer in grams per liter. What is the solubility of PbI2 in 0.1 M NaI (aq)? Express your answer in grams per liter.
Saturday, December 21, 2013 at 10:05am

chemistry
A slab of plate glass containing dissolved helium is placed in a vacuum furnace at a temperature of 400 C to remove the helium from the glass. The concentration of helium is constant throughout the glass before vacuum heat treatment. After 10 minutes in vacuum at 400 C, at ...
Saturday, December 21, 2013 at 10:04am

chemistry
A pressure vessel is lined with a membrane to reduce the loss of helium. The membrane is made of a material through which the diffusivity of helium at 25 C is 3.091 x 10-10 m2/s. The concentration at the inner surface is maintained constant at 4.00 x 10-6 kg/m3. The ...
Saturday, December 21, 2013 at 10:03am

chemistry
Composition A: 5% MgO - 95% SiO2 Composition B: 20% MgO - 80% SiO2 The two glasses above are soaked in molten calcium chloride (CaCl2) at the same temperature for a time long enough for the properties of the two glasses to approach a steady value. What glass will have the ...
Saturday, December 21, 2013 at 10:02am

chemistry
On the basis of electrical measurements, it is concluded that the equilibrium vacancy concentration in a given metal is two orders of magnitude higher at 807 C than at 498 C. What is the energy of vacancy formation (ΔHv in kJ/mol) for this metal?
Saturday, December 21, 2013 at 10:01am

chemistry
Determine the amount (in grams) of boron required to be substitutionally incorporated into 1.000 kg of germanium in order to achieve a charge carrier density of 3.091 x 1017/cm3. Assume intrinsic carriers are negligible. What type of conduction will be present in this material...
Saturday, December 21, 2013 at 9:57am

chemistry
Determine if light with wavelength 3.00 x 10-7 m incident on gallium nitride (GaN) can generate electrons in the conduction band. Gallium nitride has a band gap of is 3.2 eV. Photons with wavelengths below what value will generate electrons in the conduction band of GaN? (...
Saturday, December 21, 2013 at 9:55am

chemistry
For each pair of materials, indicate which has the larger band gap. 1. GaAs BN 2. AlAs InAs 3. C Ge 4. InAs GaAs 5. InP GaP
Saturday, December 21, 2013 at 9:55am

chemistry
Draw the three dimensional structure of hydrazine (H2N-NH2) and answer the following questions about what you have drawn. How would you describe the geometric arrangement of electron domains around each nitrogen? linear trigonal planar tetrahedral trigonal bipyramidral ...
Saturday, December 21, 2013 at 9:52am

Chemistry
Determine the linear density of atoms (atoms/m) along the [111] direction of gold at 300K. What is the interplanar spacing (m) between [111] planes in gold at 300K?
Saturday, December 21, 2013 at 7:33am

chemistry
What is the minumum acceleration potential (V) that must be applied to a beam of free electrons for diffraction to occur in a crystal of niobium (Nb)? Express your answer in volts.
Saturday, December 21, 2013 at 5:46am

Solid State Chemistry
Which molecule ( KI or LiF ) has the higher boiling point? Select the single most important reason below to justify your choice should have the higher melting point Both molecules are nonpolar but the higher melting includes hydrogen bonding Both molecules are nonpolar but the...
Friday, December 20, 2013 at 3:07pm

Pages: <<Prev | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | Next>>

Post a New Question | Current Questions

Homework Help: Science

Search
Members