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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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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...
RP
Answered by Reena P. • Maths tutor
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Vous êtes en vacances et vous envoyez une carte postale à votre ami. Dites où vous êtes, le temps qu’il fait, ce que vous avez fait et ce que vous avez l’intention de faire pendant le reste du séjour

Coucou Fleur! Ça va? Moi, ça va super bien! Je suis en Espagne à Malaga avec ma famille pour mes vacances. Nous logeons dans une villa au bord de la mer, c’est fantastique! Ici il fait très beau et très chau...
MH
Answered by Mariam H. • French tutor
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How can I identify components of a website?

We've all been on websites before, at this precise moment you are interacting with one. You have to just remember the specific names that are used for each component. A website banner is an essential and mos...
KC
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Why do different blood vessels have different lumen sizes (relative to their overall size)?

Lumen sizes in blood vessels differ due to the differing functions of the vessels themselves. Arteries have to carry oxygenated blood away from the heart to the tissues at high pressure. Small lumen (relativ...
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Answered by Jessica S. • Biology tutor
82851 Views