Homework Help

Hi there! i'm a new user here. I decided to sign up because I'll need somewhere to go for answers for science questions, other than my parents. So, I have a test for 7th grade science tomorrow; and I have a question that needs to be answered: Why does indirect light cover more surface area than direct light? Thanks for your time and effort! Merged post follows: merged postHey guys! Can you pls tell me how to explain why indirect light covers more surface area than direct light? I already understand the concept, but I don't know how to explain it.

help me b4 exams

1. The problem statement, all variables and given/known data An ice cube melts in a 10oC glass of water (mass of water is 225g). If the ice is allowed to melt completely, what will the final temperature of the water be? (we're told that the mass of ice can be ignored) Ti = 10oC Latent heat of fusion = Lf = 334000 J/kg specific heat capacity of water = C = 4180 J/kg/oC mass of water = Mw = 0.225kg 2. Relevant equations: QH = sensible heat = mC(T2-T1) QE = latent heat = m*Lf 3. The attempt at a solution I have figured out an equation that requires the mass of ice to be included, however we've not been given the mass of ice (and are told to ignore it), so I'm not sur…

Please help me to solve this problem(give me some hints). Thank you so much! A sample of cocaine, C7H21O4N, is diluted with sugar, C12H22O11. When a 1.00mg sample of this mixture is burned, 1.00mL of carbon dioxide(d=1.80g/L) is formed. What is the percentage of cocaine in this mixture?

Hello, I am trying to determine the identification of an unknown. My boiling point is some where between 129- 134.7 Celsius. My Refractive index was 1.392 after being corrected for room temperature. It was not soluble and water and was less dense. MY IR spectroscopy is attached below please help I have been unable to identify this compound for about 4.5 hours now. Best regards, N2Microbes also on another note it smells like bananas

https://gm1.ggpht.com/5dtYUGWsGvYFv3l_Bn7uw-mHEnAn09fTlWtC-1hwEThg-VNW_4HjvcxTzlblmiZdMkqZlMQzIwrTYAsfP91rJVrSfbxcYUv3qBtQrkfJgj-TQSKVck1qZZJsmMzBSHPUgtVqTu1BdYh1end-F8dvTkYUSj_HmohBgRvnm9Fq-WHDmUUjVnjTaA1_E54wuWH028_wvoF2YSltkei9v8AIOr7FCqQCcbWiUX7R1ygTCta9DBqLs5GL7xTBy9IkLoVe7dbTLW-A6MIMOu1ce-rNXQcdOXANjwiL77KgC4GBRLvLX-w2WnvhNwlgs18m6PuvJ7UerYU8y4z36ePl6-atF8fZsqahm8aDPyazUJ9__cmNpkEZHB1wMU4Z_SvkjDFoBjm2Xn8Ash6fysIaS3PUl7_apuVhHrMhrsa_mC7ckjXPdbaMsvqS_wZXv11aE3917Z57H02eYt3G0DHmKaYQgOkBmIBLaqdH83EQXxXtweKyJxCsmM1rqPkG1OyXH3eSvRXFoeZND_IM7Mwt8QHmY0sfXuLxxYSQFSxOP_ncSps_AyAk7jSA0QmFGCZogLL4zFOEfSAAPcoHrqyvGmby__q6fvcGpgdF3aXg2oyDGFpaxEMoqfloY810i61iZGZh8VzHmcY5j9zOYKiemM…

I am supposed to do a lab experiment that shows The Effect of low pH on Enzyme Activity. I will be using yeast as a catalase enzyme and hydrogen peroxide as a substrate. I was going to use vinegar, bleach and distilled water for pH levels but I am not sure if that is right. The project isn't about any pH level but low pH. It is supposed to test the effect of an acidic fluid on enzyme activity. I started thinking that maybe I should just use vinegar to test it and distilled water. I plan on using the distilled water as a control. Does it make sense to just put distilled water with peroxide and no enzyme? The more I think about it, the more confused I get.

Apologies for the stupid questions but I have confused myself. I was separating out blood components in lab- column chromatography- and now we have to calculate Na+ content of each fraction collected (in μmoles) and the protein content of each fraction in mg. Each fraction was 1.5ml. The Na+ concentration in mM and the protein concentration in mg/ml were read off standard curves. For the sodium, the samples were diluted (0.5ml of blood serum with 9.5ml water). Would I be right to use the full 10ml amount rather than the 0.5ml amount in my calculation? And do- n=c(changed to M) v (changed to litres) = .... then change the finial answer to micro moles. For the prote…

Hi, I'm sorry to post here but i need help for my exam. I have pre released material to prepare and there is no one to help me. It was supposed to be done by the school teachers but they don't do it properly they did very few things. I wonder if you can give me the answers. I would be very grateful to you. Its my last year exams i need to pass. See the attachements and post the asnwers in (Visual Basic 2010 language) only. Thanks Its only Paper 2 - Fundamental Problem-solving and Programming Skills. Oh and i tried to attempt page 7 but i'm not sure if its good. You tell me if you know it. Paper 4 will post later. You post you answer in image form no prob…

If 1.20 grams of salicylic acid is reacted with excess methanol, what mass of ester should you expect to achieve theoretically? Molar masses of.. salicylic acid is 138.13g/mol methanol is 32.05g/mol ester (methyl salicylate) is 152.16g/mol Mole ratio 1:1 My work: 1. 1.20 g salicylic acid (1 mol salicylic acid/138.13 g salicylic acid) = 0.008687468 mol salicylic acid 2. 0.008687468 mol salicylic acid (1 mol ester/1 mol salicylic acid) = 0.008687468 mol ester 3. 0.008687468 mol ester (152.16 g ester/1 mol ester) = 1.32 g ester so 1.32g of ester would be expected. Is my work correct? or do I have to use the excess reagent to find the mass of the product?

A granite plate freely supported at its ends spans a gorge 20m wide. How this does the plate have to be if granite fails in tension at 20 MPa? Assume density is 2700 kg m^3. This is a question in the textbook "Geodynamics" by Turcotte and Schubert. It is a question in chapter 3 (Elasticity and Flexure) question 3-14. I've been working on this for two days and cannot figure out how to solve the question. I know the answer is 0.405m from the back of the book. I cannot figure out the equation to use for the problem. I have tried multiple equations from the book and I haven't figured out which equation to use. Thanks!

Problem 3.14 A granite plate freely supported at its ends spans a gorge 20 m wide. How thick does the plate have to be if granite fails in tension at 20 MPa? Assume ρ = 2700 kg m−3. Hello, I must resolve this problem ("Geodynamics"), but I don't understand the methodology to obtain the answer (0.405 meter). If someone may explain me how begin this problem, I'm very interested. Regards Artorius

This is the question, 5 replicate estimations were made on a sample and the average absorbance was 0.148 A 0.45ml aliquot of the same sample was then 'Spiked' with 50ul of a 500umol/L creatine solution and re-assayed. The average absorbance of the mixture was 0.138 State with reasons what effect, if any, the creatine had on the assay. You should show data manipulations to support your arguments/conclusions. I have no idea how to do this Does anyone know how to go about solving this one out?

Can someone help me with this problem? I know the formula is pH=pka + log [A-]/[HA]. Are the pk values the same as pka? What is the acid value and conjugate base value? I'm not sure how to go about this problem. Any insight would be appreciated! the amino acid histidine has 3 hydrogens that could be titrated with pk values of 1.82, 6.0 and 9.17. Describe the pH ranges in which histidine could be used as a buffer and explain why histidine might be a good candidate for buffering the intracellular pH of cells

Hi, I'm having trouble with this Chemistry question for my homework. Here it is. Two processes are needed to obtain propene from crude oil. (i) Name these processes in the order in which they are carried out. Process 1: Process 2: (ii) State the conditions used in industry to carry out process 2. I know that one of the processes is to heat the crude oil to a high temp in a catylst, but i'm not sure which process that is and what the other process is. Thanks to anyone that can help, - Harry

You are provided with the following information: (i) the sequence of a cDNA fragment of the gene encoding a cell-surface plasmodium receptor. (ii) an expression vector containing T7 promoter and multiple cloning site including EcoRI and BamH restriction sites. a. Describe how you would clone the coding region fo the gene into the expression vector provided.

How much energy is required to lift a 4500 lb car 16 inches? Express in lb-ft, joules and btu. i am a beginner in physics and i am having trouble finding how to do this problem.

Please help me answer this question: You are provided with the following information: (i) the sequence of a cDNA fragment of the gene encoding a cell-surface plasmodium receptor. (ii) an expression vector containing T7 promoter and multiple cloning site including EcoRI and BamH restriction sites. a. Describe how you would clone the coding region fo the gene into the expression vector provided.

Q: Enzymes are classified into six major groups according to the type of reaction they catalyse: What class of enzyme is phenylalanine hydroxylase? What general type of reactions does this class of enzyme catalyse? How does the enzyme phenylalanine hydroxylase generate tyrosine?

i have an equation i can't solve analitically. my goal is to find a simple solution for h(t) as a function of t, not an exact solution but a simple exponent of t will do i.e h is proportional to t^(alpha) i need to find that alpha. my equation is a simplified reynolds eq(based on lubrication approx) with b.c and i.c attached my methods are solving the eq for p and than for h since h does not depend on x. please help me!

I saw this .GIF online and I am wondering what Experiment this is?

So, I am doing a free-fall lab for my physics class. We got the values and I have the results here(we used a infrared photo-gate). Basically, we have a brass cylinder and a wood cylinder. Each are dropped in the middle of 5 infrared photo-gates before hitting the ground, which calculate the velocities and the time at which they passed through. We had 4 trials done(the recommended amount). We needed to calculate the acceleration to determine whether it was approximately equal to 9.81 m/s^2. However, when calculating the acceleration, we got weird results. First, we decided to subtract the velocities between gates and subtract the times between and then divide …

Hi all i have a calculus problem Differentiate with respect to the variable y=1/3cos-1(x/4) i completed this using the inverse cosine function y=cos-1(x^-4)/3 function -1/root a^2-x^2 Differentiated dy/dx=(1/root4^2-x^2)/3 Brought in the 3 for dy/dx=0.3x(1/root4^2-x^2) at this point i cant really see how to simplify this further. Can it be done. are the current steps correct? Thank you

In my renewable energy sources class I've been stuck on this problem, and it doesn't help that the book itself is vague and doesn't really allude to any examples pertaining to this. I've attached my work and problem, and I'm trying to see if someone could nudge me in the right direction because I'm completely lost. The answers were suppose to be 2.7 and 650 but I can't get that nor can I understand where to go.

I have: [latex] C=\frac{\lambda}{\mu}e^{-({\mu} - {\lambda})t} [/latex] I just want to make lambda the subject, but things got a little messy. After rearranging, differentiating and solving the quadratic I got an explicit solution. I've attached my solution as a jpeg file (was having a nightmare with LaTex). Would anyone care to have a check for mistakes, it got messy so i wouldn't be surprised if there were.