OCR chemistry...please help

    • Thread Starter

    Okay, I am trying my best to achieve an A or A* grade in ocr chemistry gcse, and I think I can do it, if I learn how to do the hard equations in C5. A question I just attempted (and epically failed at..) was this one:

    KOH + HNO3 -> KNO3 + H2O

    The concentration of potassiumhydroxide solution is 0.100mol/dm3

    Calculate thenumber of moles in 25.0com3 of potassium hydroxide solution

    Hey! First of all, you must convert the cm3 used in the volume into dm3, which you do by dividing it by 1000.

    So the volume is 25.00/1000 = 0.025 dm3.

    Then, to get the number of moles of solution, multiply the volume (dm3) by the concentration.

    0.025 * 0.1 = 0.0025 mol

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