HELP PLEAS we dissolved Alka-Seltzer in water and the mass decreased about 0.13g after mixing. The missing mass left as

12. complete each of the following word equations for synthesis reactions. a. sodium + oxygen -> b. magnesium + fluorine -> 13. complete and balance the equations for the decomposition reactions. a. hgo -> [with the triangle heat symbol above the arrow] b. h2o(l) -> [with "electricity" written above the arrow]

What is the approximate mass of 25 cm3 of silver, if the density is 10.5 g/cm3? a. 0.42 g b. 2.4 g c. 42 g d. 260 g

Equal numbers of moles of he(g), ar(g), and ne(g) are placed in a glass vessel at room temperature. if the vessel has a pinhole-sized leak, which of the following will be true regarding the relative values of the partial pressures of the gases remaining in the vessel after some of the gas mixture has effused?