Given the balanced equation representing a reaction:

2HCl(aq) + Na2S2O3(aq)--> S(s) + H2SO3(aq) + 2NaCl(aq)

Decreasing the concentration of Na2S2O3(aq) decreases the rate of reaction

because the

(1) activation energy decreases

(2) activation energy increases

(3) frequency of effective collisions decreases

(4) frequency of effective collisions increases

(3) frequency of effective collisions decreases

Explanation:

According to the collision theory , the number of collisions that take place per unit volume of the reaction mixture is called collision frequency. The effective collisions are ones which result into the formation of products.

For the given reaction :

According to collision theory , the rate at which a reaction takes place is proportional to rate of collision of reactants i.e and in the given case.

Thus according to collision theory, with decrease in concentration of reactants , the rate of reaction also decreases. This is because if the concentration of reactants decreases , the chances of effective collision between molecules also decreases. This decreases the reaction rate.

it is to be noted that an alpha particle is an helium nucleus. so it contains 2 protons 2 neutrons and has a mass number of 4. when alpha decay particles are ejected from the nucleus it gets transformed into an atom which has atomic number less than 2 and a mass number less than 4.

an equation that could represent alpha decay is radium 226 decay of alpha particle forms radon 222.

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1. for the first question, we must find the mass of the anhydrous salt, mgso₄. the molar mass for mgso₄·7h₂o is 246.47 g/mol, while that of mgso₄ is 120.37 g/mol.7.834 g mgso₄·7h₂o * 1 mol mgso₄·7h₂o/246.47 g * 1 mol mgso₄/1 mol mgso₄·7h₂o * 20.37 g mgso₄/mol = 0.647 g mgso₄

2. mass of water = mass of sample - mass of anhydrous salemass of water = 7.834 - 0.647 = 7.19 gpercent water in hydrate = 7.19/7.834 * 100 = 91.74%