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HSC Stuff => HSC Science Stuff => HSC Subjects + Help => HSC Chemistry => Topic started by: dermite on February 14, 2018, 10:07:46 pm

Title: Need some help with an LCP Qn
Post by: dermite on February 14, 2018, 10:07:46 pm

Hi there,
I need some help with the following question (Acidic Env)

(a) If a can of soft drink such as Coca-Cola is left in the freezer it may explode. State 2 possible reasons for this.
(b) Outline the effect on solubility of CO2 in water if alkali is added to the solution

Thanks in advance, any help appreciated

Title: Re: Need some help with an LCP Qn
Post by: arii on February 15, 2018, 12:24:19 am

Hey there,

(a) Based on memory, Coca-Cola is like 89% water. The water molecules expand in freezing temperatures. On a molecular scale, the hydrogen atoms in water molecules are attracted to oxygen atoms in nearby water molecules, forming a rigid structure as the water forms ice crystals. The rigid structure takes up more space than those same molecules did as a liquid, causing the ice in the soda container to expand and force out the CO2 inside it in the process. Also, the pressure of CO₂ increases as it gets cooler, which also contributes to a potential soft-drink can explosion.

(b) CO₂ + H₂O <-> H₂CO₃ <-> HCO₃^- + H⁺
(Alkali = basic) An example of an alkai is NaOH. OH^- ions neutralize H⁺ ions and cause a shift towards the products side (right).
This increases H+ ions, decreases pH and increases solubility of CO₂ in water.