Mixing two clear liquids results in the formation of a whit solid. Is this a physical or chemical change?

Calculate the number of molecules present in 0.750 mol of mgo.

He table below gives the atomic mass and relative abundance values for the three isotopes of element m. relative abundance (%) atomic mass (amu) 78.99 23.9850 10.00 24.9858 11.01 25.9826 what is the average atomic mass (in amu) of element m? 2.86 5.36 24.30 24.98

Which change will decrease the number of effective collisions during a chemical reaction? a. adding a catalyst b. increasing the surface area c. decreasing the temperature d. increasing the reactant concentrations e. increasing the volume of the reactants