Posts by Chemistry

Total # Posts: 253

Chemistry
Sorry about that The chemical 5-amino-2,3-dihydro-1,4-phthalazinedione, better known as luminol, is used by forensic scientists in analyzing crime scenes for the presence of washed-away blood. Luminol is so sensitive that it can detect blood that has been diluted 10,000 times...

Precipitates
If i used NaCl to try to precipitate Ag+ from a solution, will it be as effective as HCl?

chem
how can you fill a flask with pure oxygen without mixing it with air

REETA
A 2.10 mol sample of oxygen gas is confined to a 5.10 L vessel at a pressure of 7.99 atm. Find the average translational kinetic energy of an oxygen molecule under these conditions in (j/mol) When i was working this out i tried using pv=nrt to find the temperature which i got ...

chemistry
What is the difference between Keq and the term of [prod]pr / [react]pr?

Curious Maria
could help but i can't find that diagram ur talking about

scsu
What is the weight per volume percent (i.e. % density) of 0.5522 g acetic acid in the 10.00 mL sample?

kim
a gaseous hydrocarbon reacts completely with oxygen gas to form carbon dioxide and water vapor. given the following data, determine (delta)HoF for hydrocarbon: (delta)Horxn=-2044.5kj/mol hydrocarbon (delta)HoF CO2= -393.5kj/mol (delta)HoF H2O = -242kj/mol denstity of CO2 and ...

Jack
how does cross linking alter the properties of a polymer?

Jason
I understand that polymers are long chain 500-20,000 repeating units, but I don't know: what car components are made of polymers?

Brad
My problem is calculate the molarity of HCl and NaOH (molarity of acid)x(volume of acid)=(molarity of base)+(volume of added base) HCl=acid NaOH=base HCl volume = 25mL=0.025L NaOH=67.05mL=0.06705 molarity = moles of solute Liters of a solution M=0.015000 moles of NaOH 0.06705L...

Chem
Directions: Use the principles of atomic structure and/or chemical bonding to explain each of the following. In each part, your answer must include references to both substances. Problem: The carbon-to-carbon bond energy in c2h4 is greater than it is in c2h6. Any help is ...

Mike
N2 + 3H2 --> 2NH3 At 25°C (delta)Ho = -92.22 kJ and (delta)So = -198.53 J/K. Using this information, calculate the equilibrium constant for the reaction at 2.43x10^2°C. (R = 8.314 J/K) Apparently the way I'm doing it is wrong: I divide 198.53 by 1000 then ...

Lauren
-6783.72 J

Lauren
wouldnt it be 4.184J/g * degrees C so 4.184 J/ 162 g H2O * 10 degrees C = ?

Lauren
The specific heat of water is at 4.184J/g * degree C. How much heat is evolved, or absorbed, when the temperature of 9.00 mol of liquid water cools from 38 degrees C to 28 degrees C? How do I start this problem

Suzy
it is a linear regression of a graph I have that deals with the absorbance by the concentration I couldn't paste it on here for you to see....

Suzy
ALSO PART OF THE DISCUSSION In Figure B the line of y=0.0052x-6E-05, R^2 .9989 the .9989 is really close to 1, the closer to one the better, to go over one seems to make the lab a failure. Less than one must mean that the lab went well and was done correctly. COULD YOU HELP ME...

Suzy
Discussion: This experiment was conducted to identify the iron content in a breakfast cereal. The results indicate that there was iron in the chosen breakfast cereal of Kix, the spectrometer shows that the absorbance or color was around .39 so about 39% as seen in Figure A the...

Suzy
Discussion: This experiment was conducted to identify the iron content in a breakfast cereal. The results indicate that there was iron in the chosen breakfast cereal of Kix, the spectrometer shows that the absorbance or color was around .39 so about 39% as seen in Figure A the...

Suzy
Discussion: This experiment was conducted to identify the iron content in a breakfast cereal. The results indicate that there was iron in the chosen breakfast cereal of Kix, the spectrometer shows that the absorbance or color was around .39 so about 39% as seen in Figure A the...

Suzy
Results: The combination of the solutions: sodium acetate, hydroxylamine hydrochloride and phenanthroline solutions mixed together with the colorless iron solution made the iron phenanthroline solution turn into an orange tint.

Suzy
Methods and Materials: The 100 mL volumetric flask with the colorless iron solution was fitted with a rubber stopper. First, transfer the colorless iron solution into a 250 mL volumetric flask, since the substance in the 100 mL volumetric flask was too much. The 250 mL ...

Suzy
Methods and Materials: The 100 mL volumetric flask with the colorless iron solution was fitted with a rubber stopper. First, transfer the colorless iron solution into a 250 mL volumetric flask, since the substance in the 100 mL volumetric flask was too much. The 250 mL ...

Suzy
did you get all of it there is more than the introduction

Suzy
Introduction: This report discusses an experiment to study the percent mass of iron determined by the concentration of a colored iron solution from the absorbance of the spectrometer. This lab is designed to tell the content of iron in cereal, usually food products list iron ...

Suzy
Can some one read my lab report for me... I have it almost finished.. I just need help on the discussion part Please

Lauren
Fe(s) is an element right

Lauren
So I need to find the Hf of each of those equations

Lauren
Which of the following has a standard enthalpy of formation value of zero at 25 degrees C and 1.0 atm A. Fe(s) B. Fe2O3(s) C. FeSO4(s) D. FeSO4(aq) E. FeS3(s) and what is enthalpy or how do you find it

Lauren
The amount of heat required to raise temperature of 55.85 g of iron 1 degrees C is called its A. Change of energy B. Enthalpy C. Molar heat capacity D. Specific heat capacity E. Specific Heat.

Lauren
Use Lewis symbols to represent the electron transfer between the following atoms to give ions with noble gas configuations: A. Mg and S B. Ba and I

Lauren
Arrange the following in order of increasing ionic radius: I^-, Cs+, and Te^2-. Explain this order

Lauren
correct thank you for the help

Lauren
so in my book there is a chart but there is not a number for it so I can see which has a larger radius what is another way to tell which is larger they both have a 3- charge

Lauren
Which has the larger radius N^3- or P^3-? Please Explain

Lauren
so which is the correct way of increasing radius and what is a Te=

Lauren
Arrange the members of each of the following pairs in order of increasing radius and explain the order: A. Te, Te2- B. Al, Al3-

Lauren
What I don't understand is where I get the number of dots from and what is the electron configuration

Lauren
Write the electron configuration of Sn and Sn2+ Give the electron configuration of Cu+ and Cu2+

Lauren
For each of the following, write the electron configuration and Lewis symbol: A. In B. In- C. K+ D. I-

Lauren
How do I figure out how to write the lewis symbol for the following A. Br B. Br- C. Sr D. Sr2+

question for Dr.Bob22
i get how you get X = 2.077*Y, but i don't understand how if you plug in 0.481X in for Y to solve for x. x = 2.077(0.481x) x = 0.999x then what??? i know this is probably a simple stupid math question, but i need to do another problem like this and i'm stuck at this ...

question for Dr.Bob22
The mole fraction of acetic acid (CH3COOH) in an aqueous solution is 0.675. Calculate the molarity of the acetic acid, if the density of the solution is 1.0266 g mL-1. To give a different take on this, here is another way of approaching the problem. I don't claim it is ...

Jake
A combustion bomb containing 5.417 g of aluminum metal and 15.974 g of iron III oxide is placed in an ice calorimeter that initially contained 7.746 kg of ice (at o degrees C) and 7.894 kg of liquid water (at o degrees C). The reaction, once ignited by remote control, forms ...

Jake
If 142.38 g of l water at 21.7 degrees C is placed into a syrofoam cup with 174.36 g of ice at -27.5 degrees C what would be the final temperature of the entire contents at equilibrium? If it is partially frozen, how many g of the ice has melted? given values cp water = 4.184 ...

CHEMISTRY
Thank you DrBob222! I got it now!

chemistry
what does an atom of lead look like? what are the parts that compose of the atom? help me pls

Chemistry
A certain mine produces 2.5 108 kg of copper from chalcopyrite (CuFeS2) each year. The ore contains only 0.80% Cu by mass. (a) If the density of the ore is 2.0 g/cm3, calculate the volume of ore removed each year. (b) Calculate the mass of SO2 produced by roasting (assume ...

Jennifer
I asked this question yesterday and it was answered, but I still have a question on it. Standard entropies for substances are defined at a pressure of exactly 1 bar in some books or exactly 1 atm(760 torr) in different books. For gases, this correction factor would be..... in ...

Jim
I need some help with calculating percent yield and percent purity of aspirin. Here's my data (questions follow): SYNTHESIS Mass of salicylic acid.., 2.0 g Volume of acetic anhydride.., 5 mL Mass of watch glass.., 22.10 g Mass of aspirin and watch glass.., 28.01 g Mass of ...

Chemistry
Which of the following does form a Group II cation? lead iron cobalt nickel How do you figure this one out? You must know what is in group II. Fe, Co, and Ni are in group III. Pb is in both group I and group II. Pb ppts as the chloride in group I and as the sulfide in group II.

Chemistry
Al3+ and Pb2+ act as acids or bases in acidic or alkaline environment. True or False? I think this is true because they are amphoteric, but I am not sure. yes. They are amphoteric.

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