Physics, Chemistry, Mathematics Forums

Why do we say that the gravitational power of the earth is maximum at the poles and it is minimum at the center ?

A disc shaped photoelectric detector of area 0.5cm² generates current when light of frequency greater than that of yellow light falls on it.The photoelectron generation efficiency is 20%.In the arrangement shown(please refer to attachment),S is an isotropic 100 W point monochromatic light source with wavelength =4000 Å.The focal length of lens is 20 cm and its circular area is 4 cm².Find the photocurrent in the detector assuming all rays to be paraxial wrt lens.

Hi, I have a few questions that I am struggling with. Any help would be greatly appreciated.

Question 1

Calculate the molar mass of calcium chloride dihydrate, CaCl2

Please use the Periodic Table values rounded to the hundredths place for your calculation and round your answer to the hundredths place and remember, the "dot" (

Question 2

What is the theoretical yield of calcium carbonate if 2.97 grams of calcium chloride dihydrate reacts with excess sodium carbonate according to the balanced chemical reaction shown below?

Please use molar mass values calculated and rounded to the hundredths place, and round your answer to the hundredths place.

Question 3

What is the percent yield of calcium carbonate if your theoretical yield was 2.07 grams, and your actual yield was 1.46 grams, from the balanced chemical reaction shown below?

Please round your answer to the tenths place.

CaCl2•2H20(aq)+Na2CO3(aq)->CaCO3(aq)+2NaCl(aq)+2H20(I)

• 2H2O.•) means closely associated, reprsenting the ADDITION of two waters of hydration to the calcium chloride formula unit.

5.2g of a limestone sample was dissolved in dil HCl and the solution was made upto 1 dm³. 25cm³ of this solution was treated with ammonium oxalate. The resulting ppt. of calcium oxalate was titrated aganist 0.111N KMnO₄ in acidic medium. The end point was 22.2cm^3. Calculate the percentage of calcium carbonate in the sample.

hi,
i want to ask all of you. how to make acetophenone by eugenol. cause to make it, i always failed.. please help me,when i did the reaction by AlCl3, the result is polymer of eugenol...
thanks..

Given the family of lines : a(3x+4y+6) + b(x+y+2) = 0. Find the equation of the line of family situated at the greatest distance from the point P(2,3) .

I have the answer as : 4x+3y+8 = 0

Let(x,y) be the point w.r.t. to an oblique axis,and (x',y') be another point w.r.t. another oblique axis with the same origin.If formula of transformation is x=px'+qy' and y=p'x'+q'y'. Then find the value of p^2+p'^2-1/q^2+q'^2-1 The answer I have is pp'/qq'.

An organic compound (A) contains C,H,O & Cl. It reduces Fehling`s solution and on oxidation gives monocarboxylic acid (B). B when distilled with sodalime gives sweet smelling liquid (C) which can also be obtained by heating (A) with alkali. (A) can also be obtained by the action of chlorine with ethyl alcohol. Deduce the structure of A,B,C.

All the roots of the equation a₁z³+ a₂z²+a₃z+a₄=3,where|a_i|<=1,

i=1,2,3,4, lie outside the circle with centre origin and radius r:  What is the value of r?

X and Y are two sets and f: X->Y.If {f(c)=y;c C X, y C Y} and {f^-1(d)=x;dCY, XCY}, then the true statement is

a) f(f^-1(b))=b (b) f^-1(f(a))=a (c) f(f^-1(b))=b, bCy

(d) f^-1(f(a))=a , aCx

Please explain both question and answer.