Homework Help

Hi can anyone help me with this chemistry question, im finding it very difficult. If an enzyme catalysed reaction has a maximal velocity of 25micromole min-1 and km for the enzyme and substrate is 3 mM, what is the initial reaction velocity for a substrate concentration of 3 mM? please help thank you

Hi, I basically have been given this essay title, 'Human physiology is dominated by homeostasis'. using a range of named examples discuss this statement. I was just wondering what type of things i can include in this as its quite a wide topic. I will include general stuff about homeostasis, and have mentioned fight or flight response of the nervous system, and some examples of endocrine system. Any ideas let me know thanks

Hi, could someone please help me with the question below : Crystals of hydrated sodium carbonate left exposed to the atmosphere gradually lose some of their water of crystallisation. The formula of the crystals may be given by Na(2)CO(3).xH2O where x has a numerical value between 0 and 10. 16 grams of the crystals were dissolved in water and made upto 250cm3 in a standard flask. To determine the value of x, 25cm3 of the sodium carbonate solution were titrated with 1.0M hydrochloric acid. 15cm3 of the acid was required for neutralisation. (1) Calculate the mass of sodium carbonate (Na(2) CO(3)) in 16 grams of the crystals. (2) Calculate the value of x in the formu…

Hello all: I have to do a five to seven page paper on the differences between men and women in Science. Any one have any ideas?

hello friends, i have one problem regarding occilation topic.i am posting problem defination pls provide me the solution as soon as possible. Que:the Displacement of a particle in Simple harmonic motion is given by x = 8sin(5pie*t + pie/6), where time is in seconds and displacement in meter . Find 1)displacement 2)velocity 3)Acceleration, of a particle at t=2 sec. Thanks and Regardrs, rahul.

Hello, What is a calorimeter and how is the energy transferred?Can't find any information anywhere. My experiment is about finding the enthalpy of combustion of alcohols. Where would the energy conversions be there? and where would the energy be lost at times?

Hey everyone, just a small homework assignment, hoping you could lead me in the right direction. :] 1. how would you make 3.00L of a 0.125M solution of Ca(NO3)2? 2. How many grams are in 200 mL of a 1.50 M solution Na2SO4? 3. How much 1.25% KBr solution can be made with 10.0 grams of KBr? 4. How would you make 500 grams of a 0.90% solution of NaCl from a 3.5% stock solution? 5. How would you make 1.00L of a 0.30M solution of KOH from a stock solution of 6.00M? 6. Find the new molarity if 500mL of H20 are added to 200mL of a 2.5M solution of K3PO4? M= Molarity I just need a step in the right direction, like which equation to use.…

Hi all, Can someone describe the priniciple senses within the human body and how these are co-ordinated to provide a perception/sensation of the external environment ? so what are the principle senses , im assuming the 5 basic senses e.g. smell, taste ? ? but do not know how they are co-ordinated ? anyone done a similar question to this ? Any help would be appreciated

If [math]x^2-2ax+b=0[/math] ,[math]b\neq 0[/math] and has two unequal real roots then show that [math]6a^4-2a^3-2a^2b+a^2-6a^2b+2ab+2b^2-b\geq 0[/math] I know that since the equation has two unequal real roots then [math]4a^2-4b>0[/math] but then how does this figure in the above inequality??

Ok, I am having a hell of a hard time trying to figure this one out. I used to know it, but now that its exam time, it seems to have vacated my brain. Perfect timing. Ok, So go easy on me, I know this is simple, I was looking at my old test, and I cant remember how I've done this. Its all to do with Ohms Law and Electricity, so if you remember, you may have saved me some points on my end of year exam. "The table on your answer sheet lists information about various globes when the voltage across each of them is 9V. Complete the table" Current (A) | Resistance (Omega Sign) | 2 | Blank | Blank | 1.5 | Blank | …

Please help give the IUPAC name of some kind of polyacetylene compounds as picture below many thanks:doh::doh:

Find the sign of the following polynomial (i.e whether is greater or less than zero) [math]x^4+x^3(a+b)+x^2(a+ab+b)+x(a^2+b^2) +ab[/math],given that [math]|a|<\sqrt{b}[/math] and [math]|b|<\sqrt{a}[/math] Since [math] x^4 ,x^2[/math] are positive if we can show that (a+ab+b)>0,ab>0 and also [math]x^3(a+b)-x(a^2+b^2)>0[/math] are we done??

Here is another problem that made me land on my head: if [math]sec\frac{A}{2}sec\frac{B}{2}sec\frac{C}{2}+sec\frac{A}{2}+sec\frac{B}{2}+sec\frac{C}{2} -2=0[/math] ,then one of the angles (A,B,C) of the triangle ABC is 90 degrees. How do we start??

I was trying to prove the following inequality and really got stuck The inequality is. [math]\frac{x^4+y^4+z^4}{x^2y^2+x^2z^2+y^2z^2}\geq\frac{2m+3n}{3(m+n)}[/math] for all the reals x,y,z different to zero and for all the natural Nos m,n Can we use induction here

Hey everyone! My question is simple : given a set of simple linear differential equations of the form : dx1 = f(x1,x2) dx2 = g(x1,x2), is the Jacobian matrix the same as the coefficient matrix? If this is the case, the Jacobian is only useful in cases where the differential equations are not linear? Thank you!! Merged post follows: Consecutive posts mergedBumpitty bumpitty bump.

I don't understand why, when you tap a metal pot lid, it has a really high pitch as well as resonates. I understand (or I think) that if you hit something, it will vibrate, and since a pot lid is a circular membrane, it will cause resonance, but I'm not sure why. And is the pitch just because of the material itself? Or is there some other reason? Does it create longitudinal waves or transverse? So confused. @_@

I think I know what I'm doing but I'm confused. Basically I've been given this; K= [NH4+(aq)] X [OH-(aq)] / [NH3(aq)] X [H2O(l)] I've been given the values; K= 3.19x10^-7 NH3(aq)= 1.00x10^-2 mol dm^-3 H2O(l)= 55.4 mol dm^-3 So I need to find the concentration of OH-. I know I have to rearrange the equation BUT since I have already been given a value for K what do I do with the H2O value? I thought I had to move that over to the left. Do I add it to K or multiply it to K?! Or am I way off?! Any handy pointers are greatly appreciated! Cheers Pete.

Hello, I have been working on these two simple calc questions and I am getting them wrong. One is: Suppose that 3 J of work is needed to stretch a spring from its natural length of 30 cm to a length of 42 cm. (a) How much work W is needed to stretch the spring from 41 cm to 46 cm? (Round the answer to the nearest hundredth.) For this one I am integrating (1/4)*k from 11 to 16 and getting 16.875 J (b) How far beyond its natural length will a force of 50 N keep the spring stretched? (Round the answer to the nearest tenth.) For this problem I am confused. I am just doing 50=(1/4)*x; this is incorrect too. I have a feeling that my problem on these two …

prove : [math] a^2+ab+b^2\geq 0[/math] for all a,b real Nos

So.. I failed the QM exam.... along with the majority of the class. Since the average was 9 out of 30, and the majority of the class did "catastrophically bad" (words of the professor), I am taking the rest of this long weekend to sulk, and then the rest of the summer to study-study-study and do some more study on this course. The professor was kind enough to give us a make-up test at the end of the summer, instead of giving us the D or C- we probably deserve with this low grade. (btw, just to save us a discussion in a moot direction - no, there's no way for a curve; yes, the course is dual-purpose for undergrads AND grads; no, I don't have a choice; yes, I have to pa…

How do we solve the system of the following equations: 1) [math] x+y+z=0[/math] 2) [math] x^2+y^2+z^2 =0[/math] 3)[math] x^3+y^3+z^3 =0[/math]

Solve the following inequality: [math] xy+(xy)^2 +(xy)^3>14[/math] needless to say i have no idea how even to start this inequality

Hi, I'm currently taking a microbiology lab this summer (btw, I love this lab it's a lot of fun!), and I have a few questions. They aren't "HW" questions, just me curious wanting to know why (sometimes I think the bane of my existence as I'm always asking the how's and why's behind things, drives my family crazy sometimes.lol.). First one is regarding negative staining. Why don't you heat fix the slide for negative staining? I know for others, like Gram stain, you need to but what would heat fixing do for a negative stain? Would it cause an encapsulated cell to show no halo? The 2nd concerns acid fast bacteria. Why are they gram positive? I know the differ…

Find the reals x,y,z satisfying the following equations: 1) x+y+z = 0 2) [math] x^3 + y^3 + z^3 = 3xyz[/math] 3) xy + yz + xz = [math]a^2[/math] when a=0 and when [math]a\neq 0[/math]

For what values of a and b does the following inequality hold: [math]a^2+ab-4a+3>0[/math]