Homework Help

I have 42.1167g of Na2CO3. DIVIDED BY RRM (105.99) = 42.1167/105.99 = 0.397mol. Now, I want to find out how many moles there are in 250cm3 when the powder is dissoved in water. Would that be: 0.397*(250/1000)= 0.0993mol? Then, therefore, would (0.0993/250) *1000 get to moldm-3, molarity? I've repeatedly confused myself with something I was able to do a few weeks ago... and a couple of years before that.

[math]\frac{(1+h)^2 - 1}{h} = \frac{1 + 2h + h^2 - 1}{h} = \frac{2h + h^2}{h} = \frac{h(2 + h)}{h} = 2 + h[/math] I'm currently using one of the forums tutorial on calculus... And i'm stuck with a problem. The problem is i know it works out because iv'e substituted "h" with an actual integer, and my dilemma is i can't figure out how it went from, [math]\frac{(1+h)^2 - 1}{h} = \frac{1 + 2h + h^2 - 1}{h}[/math] Ignore the /font font=monospace thing, can't figure out how to remove it

1. Why are π to π * transitions on conjugated double bonds such good absorbers of visible light? 2. Intensity of the HeNe laser (λ=632nm) was measured at 2 distances: 1 m and 200 m from the laser. The meter reading was 10W and 1 W correspondingly. How many photons/sec will enter your eye if you look into the laser from 1 m? From 200 m? Assume that radius of the pupil was 2.5 mm, radius of the detector was 3.5 mm. At a distance of 1 m the laser beam radius was 1 mm. 3. Chl has an absorbance peak at 435nm (Soret band) and a peak at 665nm (Qytransition). Calculate the energy gap (in Joules) between the ground and excited states of these two transitions. An…

hey guys l need your help in my assignment l don't understand what the question wants me to do. .."The transition energy of atomic hydrogen are given by the Rydberg formula 1/lambda= R(1/n2 - 1/m2) where n and m are principal quantum numbers of the two levels. The highest energy series (Lyman) has n=1. Lyman 2 occurs at 97492 cm-1 . Calculate from this value of R(Rydberg Constant) and hence the wavelength and transition energy for Balmer 1.thanks guys!

QUESTION: Describe all the protons that are chemically equivalent to each other, and magnetically to each other. Then, give the Pople notation describing the proton spin system(s) in the molecule. Full marks for proper justification http://imgur.com/VXhQl ATTEMPT TO SOLVE THIS: For the methyl that's 'dashed', I know that the 3 protons on it are chemically and magnetically equivalent. For the sake of naming it, I assigned it as A3. However, I forgot 'why' it is that this is the case. Can somebody remind me of the reasoning behind this? For the wedged proton, I figured that it just stood on its own. Since it's the only proton on that carbon, I called it B.…

Hi guys, So there's a science fair that I'm participating in and I want somebody to bounce off ideas with me so I could come up with the perfect one. I'm thinking my theme for the science fair is environmental cuz that's the stuff that I'm more interested in. Right now, I'm just thinking biofuel/biodiesel and all those boring stuff...definitely not going to win. So... What are some major environmental issues that's going on around the globe? Extinction of species of any kind? New ways for renewable energy that I could expand on? It'd be nice if I could start with something. Thx in advance!

Here's a general chemistry problem and my answer. Would anybody mind checking it? Thanks in advance. 3 Compounds have the following mass ratios of Oxygen:Nitrogen A) 1.143 g oxygen:1 g Nitrogen B) 2.286 g oxygen: 1 g Nitrogen C) 2.857 g oxygen: 1 g Nitrogen Show that these compounds obey the law of multiple proportions. To do this I compared the three compounds to each other. My answer is: A:B = 1.143 g O:2.286 g O = 0.5:1 = 1:2 A:C = 1.143:2.857 = 0.4:1 = 2:5 B:C = 2.286:2.857 = 0.8:1 = 4:5 This whole process seems so sketchy and I was hoping somebody could check this for me. Thanks

The DNA for an H chain in a B cell making IgE antibody for Tularemia has the following structure: 5′-5'—V8—D4—J2—Cε—Cα2—3'. How many individual rearrangements were required to go from the embryonic DNA to this B-cell DNA? I know IgM is the embryonic immunoglobin, so the rearrangements occur from that one. But I have no idea how you figure out which arrangements occur because can't there be thousands of possibilities for the IgM? Also I know IgE has an extra component on the H chain but doesn't IgM have an extra one as well or am I just imagining things? My guess was 4 individual rearrangements but I'm definitely not sure if that's correct.

we have dis competition in school in which we have to take sumthing electronic, dissasemble it and use the parts to make sumthing. Now me and my friends have a cd drive(r/rw), a USB optical mouse, a digital camera and a HP all in one printer (print copy scan). Please give me some ideas on what to make from d parts of these things..need help fast...Thanks in advance

Hi, During the transpeptidation reaction in peptidoglycan biosynthesis when the peptides are cross-linked, is the terminal D-alanine lost [i.e. in E. coli when DAP forms a peptide bond with D-ala of the new disaccharide]? Or does the terminal D-alanine remain and is later cleaved by the carboxypeptidation reaction. Essentially, I'm confused by the difference between transpeptidation and carboxypeptidation. If someone could help me clear it up that'd be great! Thanks!

Hi everyone. I have a question regarding mechanic hoist system of a sailboat. Thanks a lot for your help. Cheers. Your team have been commissioned to design a system to hoist a 250Kg sail up a 35m mast using a winch on a competition class yacht. Speed of hoist is of the essence and the client would prefer that only one grinder (crew) is used. List the assumptions that need verification and the calculations that need to be done in order to achieve a satisfactory conclusion to this commission. A brief explanation as to why you have included each item should be presented.

Hello, I have been having issues getting going with this assignment in csc131. I am to write a CLI program in python where all cards are dealt face down initially in a rectangular grid. On each turn, the player identifies two of the face-down cards. These two cards are (briefly) flipped face-up. If they match, they stay face up. If they don't match, they're flipped back over face-down. The play continues until all cards have been matched; no face down cards remain to be tested. And the grid is determined by a prompt from the user. (At most 9x8 or 8x9) My first issue is creating the list for the deck. I will need to have 2 of each card and I'm not sure how to create the li…

Hello all! I am having a serious conceptual problem here... so our question is: Does it make sense for a processor to have a floating-point square root functional unit but no integer divide unit? I'm going with sometimes, I believe that both functions can be emulated using the hardware given and will give the exact same result and precision...however I am not understanding in what situations one would be better than the other? Can anyone point me in the right direction? I have read all sorts of papers and publications but I am not finding exactly what I need... thanks in advance!

I have no clue where to start but I think it is safe to say that my forward primer could be TAC and my reverse primer TTA (complementary sequences of the start and stop codon) but I dont know what to do after...the problem seems very overwhelming to me! I would like someone to provide me some hints to tackle this! Thanks everyone!Thank you for your help! Question : Write the sequence of two oligonucleotides that will allow you to clone the coding region of gene x in the vector pQE60 using PCR . The coding sequence must be in frame with the ATG of the vector. The histidine tag must be present at the C-terminus of your recombinant protein. The oligos mus…

Hello all, I have absolutely no clue how to start this problem and I would like to have some cues or just something to chew on...thank you!! I know what a plasmid is , I know what sticky ends (cohesive extremities) are but I dont know how the multiple cloning sites in this plasmid are located so im a bit lost! Question: U must clone a DNA fragment having Sau3A sticky ends. The plasmid to be used for the cloning experiment has the following MCS EcoR1, BamH1, Xba1, HindIII *Describe how you would do the cloning experiment. Restriction enzyme recognition sites EcoR1 = GAATTC (the enzyme cuts after the G) BamH1 = GGATTC (the enzyme cust after the first G) Xb…

Can anyone help me with answering these questions? I have mid-semester exam coming up and there are no answers provided for these practice exam.. Q1.An obsessive water drinker ingests approximately 10 litres of water within a day. Select whether each of the following would increase, decrease or not change with the ingestion of 10 litres of water within a day. (i) ECF Osmolarity. (ii) Mean Arterial Pressure. (iii) Vasopressin release from pituitary. (iv) Water reabsorption in the kidney (v) Renin release from granular cells (vi) Angiotensin II levels (vii)Aldosterone levels (viii) Sodium reabsorption in the kidney Q2. In a normal kidney, glomerular filtration …

A.) bONDING B.) VESPR C.) formal Charge D.) hybridization E.) Octet Rule F.) Valency G.) oRBITAL tHEORY H.)Resonance. Using these answers choices why is: 1.) NH4 more acidic than NH3 2.) CH2=CH2 is more acidic than CH3-CH3 3.)Formal Charge of H3O IS +1 AND BH3 IS ZERO 4.) CH2=CH-NH2 IS LESS BASIC THAN CH3-CH2-NH2 5.) H-O-CO-CH3 IS MORE ACIDIC THAN H-O-CH2-CH3

Hello and thanks in advance. 1) Below is a list of common weak acids that can be used to prepare buffers. Listed with each is the pKa for the first proton removed. Weak Acid pKa Conjugate Base H2C2O4 1.19 HC3H5O3 3.86 HC2H3O2 4.74 NH4+ 9.74 For each weak acid, list the chemical formula for the conjugate base in…

This is for physiology lab, so if anyone out there can help me with this, I will worship you. If a 7 year old female patient has a high lymphocyte count of 42%, neutrophils = 51%, Basophils= 1%, Eosinophils = 2% and monocytes = 4% ....what would the likely explanation be of the lymphocytes being out of range AND how many of those cells would be present in 1mm3 of blood? The patients total white blood count is 11,000/mm3. Additional Info: My textbook noted that the following was considered normal WBC, hence how i figured the female patient's lymphocytes were high: Neutrophil 54-62% Eosinophil 1-3% Basophil less than 1% Lymphocyte 25-33% M…

Lagrange Problem max [math] y = x_1^2 + x_2^2[/math] such that [math] \frac{x_1^2}{25} + \frac{x_2^2}{9} -1 =0 [/math] [math] \frac{df}{dx_1} = 2x_1 + \frac{2x_1\lambda}{25}[/math] (1) [math] \frac{df}{dx_2} = 2x_2 + \frac{2x_2\lambda}{9}[/math] (2) [math] \frac{df}{d\lambda} = \frac{x_1^2}{25} + \frac{x_2^2}{9} - 1 [/math] (3) Dividing equation [math] \frac{1}{2} [/math] [math] \frac{x_1}{x_2} = \frac{9*x_1}{25*x_2} [/math] As you can see the x_1 and x_2 just cancels out. Do you know what the issue is? I tried using a quadratic, but it still has the lambda in it, so I cannot solve it that way. How can I solve this one using the Lagrange?

Hello! I perfectly understand that thee "answer" is not permitted to be given to me, but any walkthrough in helping me understand the question would be greatly appreciated! I'm taking chemistry online and have to read the text and understand the chapter independently and it's quite challenging! I haven't been able to find any example of the question in the text, I swear the chapter questions were made not even based on the chapter, LOL. But I really want to learn chemistry!!! HELP! Here's the ?: -Nail polish remover containing acetone was spilled in a room 6m x 5m x 3m, and 3600mg of the acetone evaporated. Calculate the concentration of acetone in units of microg…

I'm looking for fish owners to take part in a short (5 minute) online survey and follow‐up after a month. It doesn’t matter if you own a goldfish or an intricate saltwater aquarium. All fish owners are invited to participate. The study explores how we can better provide information about fish care and is part of a larger PhD research project on ornamental fish at The University of Western Australia. To find out more about the survey and take part, please visit https://edu.surveygizmo.com/s3/1012880/fish This study is purely for research purposes and has been approved by The University of Western Australia’s Human Research Ethics Committee (RA/4/1/5511). You w…

I have to find the intersection position and time between two cars. But I am only given some data. Car A: Acceleration = 0 Initial position = 0 Initial velocity = 40m/s Car B: Acceleration = -2m/s^2 Initial position = 4000 Initial velocity = 0 I have no idea how to use these numbers to my advantage. Any help?

Thanks Is it a problem with the induction proof? I'm not sure how to start.

I have no problem knowing how to find the right sig-digs when just doing one of: adding, subtracting, multiplying or dividing. But, I know doing them all at once in more complicated equations gets trickier. For example, something like 110.0 + (500434.0 - 34.0)/0.37 This is my thought process for finding sig-digs when addition/subtraction is combined with multiplication/division. The answer may be correct by luck, but I know that this is not the right way to come up with the correct number of sig-digs. 110.0 + (500434.0 - 34.0)/0.37 = 110.0 + 500434.0/0.37 = 110.0 + 1.4*10^6 (I make 500434/0.37 equal 2 sig digs because the denominator only has 2 sig-digs.)…