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A student wishes to determine the concentration of sulfuric acid. They run a titration and discover that 62.5cm^3 is needed to neutralise 20cm^3 of sodium hydroxide of concentration 2moldm^-3. Work out the concentration of the acid.

To answer this question the first thing that needs to be done is to write a chemical equation, making sure it is balanced and includes state symbols:H2SO4 (aq) + 2NaOH (aq) --> Na2SO4 (aq)+ 2H2O (l)Next w...
EC
Answered by Ellen C. • Chemistry tutor
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In aqueous solution, sulphuric acid dissociates into ions in 2 stages. The pKa for the first dissociation is -3. Calculate the pH of a 0.025 mol dm-3 solution of sulphuric acid using the pKa value of the 1st dissociation.

Ka = 10 -pKa = 10 --3 = 1000[H + ] = √ Ka [0.025] = √1000 x 0.025 = 0.791pH = -log [H] = -log(0.791) = 0.102 = 0.1
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Answered by Octavia M. • Chemistry tutor
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Balance the equation C4H8 + O2 ->CO2 + H2O

C 4 H 8 + O 2 -> CO 2 + H 2 O Want to deal with only one element at the time, recap that you can only add coefficients to the front of chemical formulae, you cannot change the little numbers (number of at...
CD
Answered by Claire D. • Chemistry tutor
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Magnesium has 12 as its atomic number, how many protons does it have?

12 -the proton number of an atom is also its atomic number
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Answered by Jacob J. • Chemistry tutor
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An isotope of Nitrogen has an atomic number of 7 and a mass number of 15. How many electrons, neutrons, and protons does an atom of this isotope have?

Atomic number = the number of protons per atom of this isotopeMass number = total number of protons + neutrons per atom Therefore, an atom of this isotope has 7 protons and 15-7=8 neutrons. As an atom is neu...
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Answered by Sophie I. • Chemistry tutor
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