textbook 5H Q3

[Ava 1D]

Hi, for this question how do you know to multiply the two values from the given table. In this case, why do you need to multiply 377k by 4x10^31k to get 1.508x10^34. Thanks

[Krishnaya Coleman Salgado 1I]

Hi!

So this is actually a case of composite equations. When two chemical reaction equations can be added together to form the given equation, and you are given the K values of the two being added together, those K values multiply together to get the value of K for the third equation. In this case, the given equation 2BrCl + H2 ---> Br2 + 2HCl can be made from combining 2BrCl ---> Br2 + Cl2 and H2 + Cl2 ---> 2HCl. The Cl2 cancels out, since it is on the products side of one and reactants side of the other. The K values from those equations are then multiplied together to get the K value of the composite equation.

Hope this helps!