Homework Help

Hi, I am stuck on this question and would really appreciate some pointers on how to solve it, The specific heat capacity of the lava is 1600 J kg^-1 oC^1. when all the erupted lava cools from the eruption temperature of 1050 degrees Celsius to 15 degrees celsius, the heat released is 2 x 10 ^15 J. I need to calculate a value for the total mass of lava that erupted. Many thanks for any advice

From the equation: HCl + H20 --> H3O+ + Cl- How much H30+ is needed to create a 2.2 decrease in pH for a 50 000L volume of water currently at pH 9.7???

hi guyz am new here! am an incoming third year and i wanted to ask you as early as now coz our school has no net. am from palawan (philippine, too far). what chemistry investigatory project can you suggest for me? guyz i need your reply as soon as possible 'coz i might be going home tomorrow or the next day., thanks a lot.

Is it t-dependent or t-independent and why? I say t-dependent and cited the definition. Not sure that is right, though. TIA

What up, I really need some help on this, I'm trying not to fail - I need to fill in blanks....( [ ] = means I filled it in ) The element called [ chromium ] has an atomic number of 24. Its symbol is [ Cr ] . When an atom of this element has a mass number of 52, the atom contains _________ protons and ___________ neutrons. The most common ion charge of this element is [ 3+ ] . How do I know how many protons and neutrons it has? I looked at periodic table and it doesn't say how many Much appreciated.

how do you solve this for u, thanks u[sinh(cu)]^2 = k where c and k are just constants.

I'm asking these questions because I've honestly never done them in class, the teacher was absent today, and I haven't been able to find the solution in the textbook: An eye of mean diamter 2.5 cm has a near point of 15 cm and far point of 120 m. 1. When this eye looks at an object placed at its far point, what will it's focal length be? 2. When an object is 1 cm from the eye, what is the power of the eye's focusing system in dioptres? I've done all the other questions that I was given, and this is due tomorrow. Once again, thanks for guiding us students.

An exercise I have problems with: In a thermos bottle with heat capacity 90 J/K there is 0.4 kg water. The temperature of the water and the thermos bottle is 313 K. Brass with mass 0.1 kg has temperature 363 K and specific heat capacity 380 J/(kg *K). It is dropped into the thermos bottle. a) What will the temperature of the water be? b) 0.02 kg ice with temperature 273 K is added. What will the temperature of the water be now? I presume that no heat will leak from the thermos bottle. I think I will manage a), but b) is more difficult. Help will be appreciated.

hey, i really need help with my osmosis coursework,any1 hav gud ideas as to how i explain that osmosis will change the weight of the potato chips??

4. List 6 types of cell found in the retina and briefly describe their functions. 5. Compare and contrast the gross and microscopic structure of the small and large intestine and briefly relate this to function. Need to write an essay from these questions if anyone can help me with the research I will be very greatfull.

How do the xylem vessels produced in a tree change within a season

Okay, the question asked me to provide an example of an element that had the properties that it specified. All the others were easy, but I'm really confused about this one: - Lacks metallic lustre - Lacks ductility - Good conductor of electricity as a solid - Very unreactive - Solid at room temperature Here's what I think: - Can't be a metal then - Metalloid or non-metal then - Good conductor? ... - Very unreactive, noble gases? (since gold was eliminated) - Solid? Not the noble gases then... So what could this element be?

6: How do the xylem vessels produced in a tree change within a season? i dont know at all no site is telling me;(

New to forum. Learning Phys I on my own distant learning. I get Trans. Equil as sum of all forces = 0 however choices not so simple. Choices are: 1) only if at rest 2) only if moving at constant velocity 3) only if it is either at rest or moving with constant velocity 4) if it is moving with either constant velocity or constant acceleration boy (unk mass)-----4m--------(fulcrum)----1m-----80kg man balanced What is downward force exerted on fulcrum? 1) zero Newtons 2) 100N 3) 600N 4) 800N 5) 1000N

Well, I've been doing Gr.12 U Chemistry and have been finding it difficult most likely because I do not have any of the prerequistes for the class. Anyways, I was wondering if anyone could verify any of my anwsers as I have been struggling with it...Here it is if anyone is interested: In cases of severe diabetes, a patient’s tissues cannot break down glucose, and, instead, the body breaks down fat for its energy. The fats are broken down in the liver and muscles, producing several compounds called “ketone bodies,” one of which is acetone. a. The acetone produced in this process is carried in the blood and urine. Explain why acetone is soluble in these aqueous solu…

does anyone happen to know what special enviornmental conditions taproots have adapted to?

It is the molecule of heredity It contains purines It contains deoxyribose and phosphate It is single Standed It contains pyrimidines

which one does not indicate compound? Co2 N2 HCI H2O NacI

Hello there! My 16 year old son is in the process of doing his science (foundation) GCSE and is really struggling with a coursework regarding 'oil droplets'. His coursework involves molecules/hydrocarbons and it seems really challenging. I would attempt to help him, however my science knowledge is severely lacking! Have any of you scientific guys come across this coursework before? If so is there anything you remember about it etc? any help/tips would be greatly appreciated! thanks, Sally

What four elements making up about 96% of body O,ca,H,Na O,C,H,N O,C,He,Na O,H,K,N O,Ca,H,Ni i AM LITTLE CONFUSED ABOUT HERE, i THINK MY ANSWERS IS oXYGEN. CARBON, hYDROGEN, NITROGEN BUT I M NOT SURE PLS HELP ME. IS THIS ANSWER RIGHT OR NO.

Hi, I really need help with this question I've tried everything! let's assume a critical/flat universe. Ho=70 km/s/Mpc. I computed Boltzman law for energy (volume) density by integrating Planck's law p rad= alpha*T^4. alpha= 7.56*10^-15 ergs/cm^3/K^4 (Which I computed to be 7.56*10^-16 Joules/m^3/K^4) I dont know where to begin with this question.. there's no other values provided . I'm supposed to somehow find out the redshift at which the universe switched from being radiation dominated to matter dominated (point of time at which radiation density is equal to mass density). and the temperature of the universe at that time .

I was doing an experiment, and I had to balance the equations. Think you could tell me if I did these correctly? [math]2Mg + O_{2} -bunsen burner-> 2MgO_{(s)}[/math] [math]2 MgO + 2H_{2}O --> 2Mg(OH)_{2}[/math] 1) Magnesium + oxygen = Magnesium oxide 2) Magnesium oxide + water = Magnesium Hydroxide

Got this (rather tricky) separation of variables problem: Expanding the LaPlace's equation, I get my two ODEs: d²X / dx² - k²X = 0 d²Y / dy² + k²Y = 0 Because one of the boundary conditions has a sin(pi*x/L) term in, I've written the general solution for d²X / dx² - k²X = 0 as: X(x) = Asin(kx) + Bcos(kx) (think that's right...) However I'm having major problems with part (b)... my natural assumption would be that the entire general solution reads as: T(x,y) = [Asin(kx) + Bcos(kx)][Ce^ky + De^ky] However using that I can't zero enough terms given my boundary conditions to get anywhere. HELP!!!!

Assume that the current age of the universe is 13.4 billion years old, and that we live in a matter-dominated, omega_m = 1, critical universe, what is the age of the universe at redshift 0.6? HINT: use the current age of the universe to pin down the proportionality relationship between age and the scale factor I know that (t_o) proportional to (1/H_o) proportional to (1/z), but I don't know how to connect this with the scale factor...and I have no idea how to "use the current age of the universe to pin down the proportionality relationship between age and the scale factor"

Hey Guys Its me men of steel here i just want u to derive me 3 equations of motions with explaination. I have been doing it but cant do it so need help here. I would appreciate that. Thnx