Science Homework Help

Indicate at what temperature the two reactions will be spontaneous  PCl_3 (g) + Cl_2 (g) --> PCl_5 (g)   ΔH° = -97.9 kJ NH_4 CO_2 NH_2...

Posted by spock2 April 30, 2013 at 1:47 PM via web. 1 educator answer. »

A coffee-cup calorimeter is filled with 50 mL water at 25°C (density = 0.997 g/mL). A 36.5-gram sample of mettalic material is taken from...

Posted by spock1 April 30, 2013 at 1:41 PM via web. 1 educator answer. »

Describe how the biodiversity of the earth has changed since the origin of life

Posted by smsms April 30, 2013 at 12:33 PM via web. 1 educator answer. »

Derive the relation of Force between any two masses.

Posted by spsaroj April 30, 2013 at 9:55 AM via web. 2 educator answers. »

How does a seed germinate?

Posted by frizianne April 30, 2013 at 1:42 AM via web. 1 educator answer. »

Calculate the percent error in Fc arising from a 1% error in measuring the radius R.

Posted by candygurlll April 29, 2013 at 10:09 PM via web. 1 educator answer. »

What volume, in mL, of 0.1234 M HCl is needed to neutralize 2.00 g Ca(OH)2?

Posted by clairelizz April 29, 2013 at 8:42 PM via web. 1 educator answer. »

Correct the statements:i) elements in the same period have equal valencyii) valency depeands upon the number of shells in an atomiii) copper...

Posted by prak10 April 29, 2013 at 3:20 PM via web. 1 educator answer. »

I need a powerpoint presentation that explains the structure and function of DNA.

Posted by jasma82 April 29, 2013 at 2:29 PM via web. 1 educator answer. »

Think of many ways as you can in which human activities are affecting the environment. Start off by listing them, but then try and put and...

Posted by jasma82 April 29, 2013 at 2:13 PM via web. 1 educator answer. »

What is the importance of nitrogen fixation in agriculture?

Posted by jamesgrey25 April 29, 2013 at 1:22 PM via web. 1 educator answer. »

What is the caecum and what are its functions?

Posted by yapperz5000 April 29, 2013 at 1:05 PM via web. 1 educator answer. »

Why should high school curricula include creationism and evolution?

Posted by sarahholmes April 29, 2013 at 1:04 PM via iOS. 1 educator answer. »

How does the diet of a herbivore, carnivore, or omnivore respectively, affect the roles of the parts of the digestive system?

Posted by yapperz5000 April 29, 2013 at 1:02 PM via web. 1 educator answer. »

State a difference in characteristics between archaebacteria and eubacteria and between gram-positive and gram-negative strains of bacteria?

Posted by yapperz5000 April 29, 2013 at 12:32 PM via web. 1 educator answer. »

Explain how the dissolved urea is removed from the blood when passed through the dialyser. State if diffusion or osmosis is involved and...

Posted by yapperz5000 April 29, 2013 at 12:28 PM via web. 1 educator answer. »

An explanation of radioactive carbon dating?   (I have to answer questions about how technology has impacted the knowledge about the...

Posted by mattlimey April 29, 2013 at 9:06 AM via web. 1 educator answer. »

why are some inherited diseases more prevalent in perticular poplulations of people?

Posted by lilone10 April 29, 2013 at 1:25 AM via web. 1 educator answer. »

What is a covalent bond?

Posted by suhhnyd April 28, 2013 at 11:01 PM via web. 2 educator answers. »

What is biomass energy?

Posted by annabanana4789 April 28, 2013 at 10:35 PM via web. 1 educator answer. »

Describe the stages of digestion where lean meat is digested?

Posted by boogey--lee April 28, 2013 at 8:28 PM via web. 1 educator answer. »

what is the molecular equation and net ionic equation for this aqueous reaction: FeSO4 + NaCl ->

Posted by elwardrm April 28, 2013 at 8:25 PM via web. 1 educator answer. »

How do you solve net ionic equations that involve precipitation?

Posted by elwardrm April 28, 2013 at 7:52 PM via web. 1 educator answer. »

Explain why covalent network solids, like diamond and silicon dioxide, are very hard, are non- conductors of electricity and have very high...

Posted by user707 April 28, 2013 at 7:29 AM via web. 1 educator answer. »

Explain why ionic substances (like copper sulfate crystls) are not malleable but are brittle whereas metals (like copper) are malleable and...

Posted by user1191221 April 28, 2013 at 7:24 AM via web. 1 educator answer. »

A substance X melts at -60C and boils at 550C. What would be its physical state at  1. -80C 2. 600C 3. 250C 4. -10C I've heard since physical...

Posted by chisko12 April 28, 2013 at 7:21 AM via web. 1 educator answer. »

A 30 000kg F-15 fighter plane is cruising at a fixed altitude with a speed of 500m/s. Find:   (a)    The kinetic energy of the plane...

Posted by trammi April 28, 2013 at 6:38 AM via web. 1 educator answer. »

can any1 plxx give me 5 difference between elastic collision and inelastic colliion..?????????

Posted by msnewbooklover April 28, 2013 at 6:25 AM via web. 1 educator answer. »

For each pound (454g) of ammonium nitrate that exploded (products being nitrogen gas, oxygen gas, and water vapor) how many kJ of thermal...

Posted by juliek21 April 28, 2013 at 5:50 AM via web. 1 educator answer. »

An aluminuium calorimeter of mass 400g contains 200g of water at a temperature of 18 degree celcius. When a block of nicklet at a temperature...

Posted by randycterry April 28, 2013 at 4:46 AM via web. 1 educator answer. »

A 100W immersion heater is used to warm 0.100 kg of glycerin from 10 degree celcius to 70 degree celcius in 2.4 min. What is the specific heat...

Posted by fukija April 28, 2013 at 4:42 AM via web. 1 educator answer. »

A technician makes 5.0 kg metal object containing one part made of iron and the other aluminium. It takes 504 kJ to change the objects...

Posted by abcdefgh2 April 28, 2013 at 4:39 AM via web. 1 educator answer. »

What mass of steam is produced when 2.00 MJ (2000000 J) of heat is applied to 5.00 kg of water at 20.0 degrees celcius?

Posted by supersmartpants April 28, 2013 at 4:37 AM via web. 1 educator answer. »

why is it not advisable to sleep in a room of green plants        

Posted by user4766696 April 27, 2013 at 1:35 PM via web. 1 educator answer. »

why sodium has valency 1 and chlorine also 1?

Posted by prak10 April 27, 2013 at 10:53 AM via web. 1 educator answer. »

What does "controlled oxidation" of alcohols (to produce aldehydes/ketones) really mean? Can you explain the process? Can you also explain...

Posted by lollypops April 27, 2013 at 1:07 AM via web. 1 educator answer. »

Can you mix an acid and a base, if you can then what is the result?

Posted by janinemurphy12 April 26, 2013 at 10:54 PM via iOS. 2 educator answers. »

What is the concentration of Ca2+  ions in a solution of CaI2 that has an I- concentration of 0.520M?

Posted by user9051586 April 26, 2013 at 7:52 PM via web. 1 educator answer. »

What volume, in mL, of 0.1234 M HCl is needed to neutralize 2.00 g Ca(OH)2?

Posted by ashweee09 April 26, 2013 at 7:51 PM via web. 1 educator answer. »

Cu + HNO3 -> Cu(NO3)2 + NO2+ H2O How many liters of NO2 gas at STP will be formed by the reaction of 75.5 g of copper with 55.0 g of nitric...

Posted by ashwee09 April 26, 2013 at 7:49 PM via web. 1 educator answer. »

why is  Lithium diisopropylamide soluble in non polar solvents?

Posted by kausik911 April 26, 2013 at 7:35 PM via web. 1 educator answer. »

why is pyrrole more reactive than furan?

Posted by arghyapikai April 26, 2013 at 7:11 PM via web. 1 educator answer. »

When are chaismata first seen during cell division?

Posted by user4530152 April 26, 2013 at 5:57 PM via web. 1 educator answer. »

What does an Earthworm's diet consist of?

Posted by popcot April 26, 2013 at 2:28 PM via web. 1 educator answer. »

1- Describe the type of cellular respiration you body cells carry out on the leisurely walk. What parts of the cell are involved in this type...

Posted by nadaazer April 26, 2013 at 2:17 AM via web. 1 educator answer. »

Do DNA codon and their complementary codon represent the same amino acids? If not, how do transcriptional proteins know which DNA strand...

Posted by Wilson2014 April 26, 2013 at 12:04 AM via web. 1 educator answer. »

What is the difference between abiotic and biotic?

Posted by mcnamshe000 April 25, 2013 at 11:12 PM via iOS. 1 educator answer. »

A chemical company plans to dig a small mine on local farmland and then build a chemical plant to extract the metal nickel from its ore. Write...

Posted by jasma82 April 25, 2013 at 9:48 PM via web. 1 educator answer. »

A scuba diver uses his waterproof flashlight to shine a beam of light so that it strikes the surface of the water at an angle of incidence...

Posted by atrinity April 25, 2013 at 4:54 PM via web. 1 educator answer. »

Complete the ray diagram for an object in front of a lens to show how to find the location and size of the image from the location and size of...

Posted by atrinity April 25, 2013 at 4:53 PM via web. 1 educator answer. »