Zadania z chemii IB SL

When sodium hydroxide solution is added to the water, a larger amount of bromine reacts. Explain this observation.

A student compiles data on the solubility of bromine in water at different temperatures from several websites and textbooks. Source Temperature / °C Solubility of bromine A 5 3.90 g per 100 $\mathrm{cm^3}$ of water B 15 1.15 $\mathrm{cm^3}$ of liquid bromine…

Suggest why hot-tub owners rarely add bromine itself to the water and instead use solid tablets that release HOBr.

In water, HOBr partly ionizes to give the hypobromite ion, $\ce{OBr-}$; the ion is a much weaker sanitizer than the un-ionized acid. The graph shows how the percentages of the dissolved bromine present as HOBr(aq) and as $\ce{OBr-}$(aq) vary with pH at 25 °C.…

Ammonia from sweat and skin-care products reacts with HOBr to form bromamines: $\ce{NH2Br}$, $\ce{NHBr2}$ and $\ce{NBr3}$. (i) Deduce an equation for the reaction of ammonia with HOBr(aq) that produces dibromamine, $\ce{NHBr2}$(aq). (ii) The graph shows how…

Hot tubs are usually kept at 38–40 °C. Suggest two reasons why running a hot tub at a lower temperature would be better for the environment.

Determine the empirical formula of HA.

A $20.00\ \mathrm{cm^3}$ sample of a solution containing 1.21 g of HA is titrated with $0.500\ \mathrm{mol\,dm^{-3}}$ sodium hydroxide solution, NaOH(aq). Exactly $27.40\ \mathrm{cm^3}$ of the NaOH(aq) is required to neutralize the acid completely. Determine…