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25 cm^3 of a solution of known 0.2M HCl is neutralised by titration by 21.5cm^3 of NaOH solution. Calculate then concentration of the NaOH solution to 3dp.

Recall n = c *(v/1000) if the volume is in Cm 3 . Now, n(HCl)= 0.2 x (25.0/1000) n(HCl) = 5x10 -3 Since the relationship stoichiometrically is 1:1 (H + : OH - ), we can infer that n(NaOH) = 5x10 -3 and by re...
WF
Answered by Will F. • Chemistry tutor
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Derive the quadratic formula (Hint: complete the square)

Firstly, the quadratic formula finds the roots of a quadratic equation. So this means f(x) = 0. A general polynomial with highest power 2 looks like: ax 2 + bx +c. Usings the two facts we just stated, we sol...
RK
Answered by Riu K. • Maths tutor
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Describe the Le Chantelier principle

If a factor affecting the position of an equlibirum is altered, the position fo equlibrium shifts to oppose the effect of the change.
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Answered by Sudip S. • Chemistry tutor
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Describe the process of nuclear fission is induced

Single and slow moving neutron strikes a uranium nucleus. This results in the nucleus to be large and unstable. The unstable nucleus splits into two unequal nuclei and some fast neutrons. The neutrons can in...
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Answered by Sudip S. • Physics tutor
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Factorise 7x^2+4x-3

look for common factors but there are not any in this case, it is a quadratic with 3 terms therefore it can be factorised into 2 brackets. First we look at the first term, since 7 is a prime number you can o...
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Answered by Reena P. • Maths tutor
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