Is a mixture of stones?

homogeneous or heterogeneous

Consider this initial-rate data at a certain temperature for the reaction described by

Voltaic cells produce a positive overall charge. what does this indicate? a. the reaction is likely to be endothermic. b. the reaction is spontaneous. c. the reaction is not likely to occur. d. the reaction is not spontaneous.

Which element has the lowest electronegativity? calcium(ca) gallium(ga) selenium(se) bromine(br)