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The glucose level is regulated in pancreas by negative feedback loop, which means that when there is too much glucose, it is removed from the blood, and when there's too little, it is released into the blood.
When there is too much glucose, beta cells in the islets in the pancreas are activated and produce hormone insulin. What insilin does is that it minds to receptors on muscles and liver and stimulate the uptake of glucose from blood. The uptaken glucose is then either used in cell respiration (muscles) or stored in a long-term form as a glycogen (liver). Thus the level of glucose decreases to the desired level.
On the other hand, when the glucose level is too low, glucose needs to be replenished in the bloodstream. Low level glucose activates the alpha cells, which produce glucagon and release it into the blood. What glucagon does is that it stimulates breakdown of glycogen stored in the liver and converts it to glucose (reverse of what insulin does in liver). Glucose is released and the glucose level in the blood increases up to the required amount.see more
Here, we have to focus on the term strong acid. It is defined as an acid that is dissolved completely in an aqueous solution. We say that the reaction of dissociation of the acid goes to completion, and we write it as HA(aq) -> H+(aq) + A-(aq). Notice that the arrow points only in one direcition, and this is because for strong acids, the dissociated form H+ + A- is preferred, therefore the reaction doesn't go the other way.
Based on this knowledge, we can define the the term weak acid, which can be seen as any acid, which is not strong acid. This means that the acid is not completely dissolved in the aqueous solution, but only partially. The reason why I derived the weak acid from the strong is because strong acid has to dissolved completely, but any acid, which dissolves only a tiny bit, or quite a lot but not completely, is considered a weak acid, so the range of the weak acid is much bigger. The equation of dissociation is HA(aq) <–> H+(aq) + A-(aq), because as it is not completely dissolved, the two forms of the acid create an equilibrium, hence the two way arrow.
With this knowledge, we can move on to the question. First notice, that this question is for 3 points, and asks us for one definition and 2 equations, therefore it is sensible to expect that the definition is for one point and so is each equation.
The distinction between strong acid and weak acid is that strong acid is dissolved completely in an aqueous solution, while weak acid is dissolved only partially. (it is safer to involve both terms strong acid and weak acid in the answer to receive the point for it.)
Hydrogen bromide, HBr, is a strong acid, hence it's equation of dissociation is HBr(aq) -> H+(aq) + Br-(aq). Hydrogen flouride, HF, forms a weak acid, therefore the equation is HF(aq) <–> H+(aq) + F-(aq).
Always write also the state of the molecules! Keep in mind that weak acids form equilibri, hence the two way arrow!see more