A student determines that an aqueous solution that contains 0.302 M sodium fluoride and 0.103 M hydrofluoric acid, also has a H3O+ concentration of 2.95×10-4 M. Based on these data, calculate the value of the equilibrium constant K for the equilibrium: HF(aq) + H2O H3O+(aq) + F-(aq)

(1) as is usually done, without the inclusion of water in the expression for K: K =

(2) for comparison, with the inclusion of water in the expression for K: K

The atomic radius of sodium is 186 pm and of chlorine is 100 pm. the ionic radius for na+ is 102 pm and for cl– is 181 pm. in going from na to cl in period 3, why does the atomic radius decrease while the ionic radius increases? a. the inner electrons in the sodium cation shield its valence electrons more effectively than the inner electrons in the chloride anion do. b. the inner electrons shield the valence electrons more effectively in the chlorine atom than in the chloride anion. c. the outermost electrons in chloride experience a smaller effective nuclear charge than those in the sodium cation do. d. the outermost electrons in chloride experience a larger effective nuclear charge than those in the sodium cation do. e. monatomic ions are bigger than the atoms from which they are formed.

Joan writes four numbers on the board in standard form, and then she writes their scientific notation

Select the correct answer a modure consists of glucose and water. what is the percent composition of glucose in the mixture if it contains 1.3 moles of glucose (cho total mass of the mature is 276 grams? ) and the a 1775