Recent content by Radwa Kamal

HELP! trigonometry Homework Statement without using calculator: prove that: sin18 = √5-1/4 Homework Equations Double-angle formulae sin 2a = 2sin a.cos a cos 2a = cos^2a - sin^2a = 1 - 2sin^2a = 2cos^2a - 1 sin^2 a + cos^2 a=1 The Attempt at a Solution let 18=a sin a = sin(90 -...

yea u r right Thanx 4 ur time

HI THERE, Although silver has d-sub-shell completely filled in atomic state and oxidation state as it loses one electron it is classified as a transition element. while transition element definition is an element whose atom has an incomplete d sub-shell, or which can give rise to cations with an...

Homework Statement Calculate the oxidation no. of Nitrogen in: NH4NO3 Homework Equations O=-2 H=+1 The Attempt at a Solution N H4 N O3 +4 -6 = -2 to make it equal zero then 2N=+2 hence N=+1 Or NH4=+1 then N=-3 NO3=-1 then N=+5

Thanx 4 enrichin me by this info in fact my study is somehow limited because am still in high school I didn't study QM calculations

I think it is purely ionic because for metals with weak metallic bond like alkaline metals it's a must to lose its valence electron completely for them they are are rarely found in covalent compounds.

Any alkaline metal hydride is ionic Ionic hydrides Ionic or saline hydride, is a hydrogen atom bound to an extremely electropositive metal, generally an alkali metals or alkaline Earth metals. source:http://en.wikipedia.org/wiki/Hydride#Ionic_hydrides

Although the electronegativity difference between sodium and hydrogen in NaH is less than 1.7 , it is ionic bond WHY??

Homework Statement If the roots of the equation ax^2+bx+c=0 are α , β and if the roots of the equation a′x^2+b′x+c′=0 are (α +γ) , (β+γ) , prove that : a′^2(b^2-4ac)=a^2+(b′^2-4a′c′) Homework Equations The Attempt at a Solution

they are awesome

I found it :) m1v1f + m2v2f= m1v1i+ m2v2i momentum before collision=2mv+zero=2mv momentum after collision=2m(1/3v)+m(4/3v)=2/3mv+4/3mv=6/3mv=2mv then Momentum before collision =Momentum after collision

Homework Statement A body of 2M(KG) mass at velocity V collided with a body of mass M(KG) at rest. The first body after collision has a velocity ao 1/3V , and the second moves at 4/3V. Verify both laws of conservation of linear momentum and energy with explanation. Homework Equations...