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# AS chemistry question im baffed watch

1. In a reaction between a solution of a metallic hydroxide, MOH, and dilute hydrochloric acid, 20.0cm3 of the alkali reacted with 25.0cm3 of the acid. The acid concentration was 4.00g per litre and that of the alkali 7.67g per litre. Calculate
(a) the relative molecular mass of the alkali,

(b) the relative atomic mass of the metal, M

I don't know who to approach this question or what do at all, I know the balanced equation is
MOH + HCL => MCL + H20 and that's just about it, if you could explain the different steps I need to take to get the answer that would be amazing, much appreciated!!1
2. sadly i cant help you as i am in the middle of revising some second year chemistry stuff (pH to be precise)
but here's a general tip for titration questions as i used to HATE them and never got them until i learnt this:

information normally comes in pairs (e.g. alkali here has a volume and a concentration)
By converting to SI units (e.g. g/dm3 to mol/dm3)
and knowing the two big formulae n=m/Mr and n=cv you can go a long way in these questions.
hope that helps you get started

another tip is to write the equation in big and on reactant side write each reactant information under the respective reactant and on the products that information as otherwise its easy to mix them up and get the wrong answer
3. (Original post by Toasticide)
sadly i cant help you as i am in the middle of revising some second year chemistry stuff (pH to be precise)
but here's a general tip for titration questions as i used to HATE them and never got them until i learnt this:

information normally comes in pairs (e.g. alkali here has a volume and a concentration)
By converting to SI units (e.g. g/dm3 to mol/dm3)
and knowing the two big formulae n=m/Mr and n=cv you can go a long way in these questions.
hope that helps you get started

another tip is to write the equation in big and on reactant side write each reactant information under the respective reactant and on the products that information as otherwise its easy to mix them up and get the wrong answer
Yeah thats helped alot, ive began the calculate and found the reacting mass of the metal how would i use the reacting mass to find find out element being used?
4. (Original post by ricardo_va)
Yeah thats helped alot, ive began the calculate and found the reacting mass of the metal how would i use the reacting mass to find find out element being used?
the only formula that uses mass is n=m/Mr where Mr is the relative molecular mass of the compound, mass you just worked out. If you can get the no. of moles its easy substitution from there

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