Zadanie 29
Reduction of which compound gives pentan-2-ol? A. Pentan-2-one B. Pentan-3-one C. Pentanal D. Pentanoic acid
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Reduction of which compound gives pentan-2-ol? A. Pentan-2-one B. Pentan-3-one C. Pentanal D. Pentanoic acid
A direct formic acid fuel cell generates electricity by oxidizing formic acid, HCOOH, with oxygen at the two electrodes, shown below as separate half-equations. Anode: HCOOH(aq) → CO2(g) + 2 H+(aq) + 2 e− Cathode:…
Which equation represents a propagation step in the radical substitution of ethane by bromine? A. Br2 → 2 Br ⋅ B. ⋅ C2H5 + Br ⋅ → C2H5Br C. C2H6 + Br ⋅ → C2H5Br + H ⋅ D. ⋅ C2H5 + Br2 → C2H5Br + Br ⋅
Which is a conjugate acid-base pair? A. H2CO3 / CO32− B. H2SO4 / SO42− C. HSO4− / SO42− D. CH3NH3+ / CH3NH−
Which methods for separating the components of the given mixtures are correct? A. I and II only B. I and III only C. II and III only D. I, II and III
Calculate the mass of solid potassium hydroxide that has to be weighed out.
Describe how the student should prepare this standard solution from the weighed solid using a 250.0 cm3 volumetric flask.
The student pipetted 25.00 cm3 of the potassium hydroxide solution into a conical flask and titrated it with nitric acid, HNO3(aq), of concentration 0.1250 mol dm−3. The burette readings before and after the titration are…
Using the concentration determined in 1c and the intended concentration of 0.1500 mol dm−3, calculate the percentage error in the concentration of the potassium hydroxide solution. If you have no value from 1c, take the concentration to be…
Explain why the potassium hydroxide solution has to be standardized before it is used in the titration. Assume that there are no systematic errors in the procedure.