50 points Please show all your work.

Dr. Nancy is researching a substance. After placing a some drops of the substance in water, Dr. Nancy measured the pOH to be 8.38 at 25.0°C. The concentration of
the unknown substance is 6.78%

The density of the solution is 0.899 g/mL

The molar mass of the substance is
143.987 g/mol.

Determine the pka of the unknown solution ???

The diagrams show objects’ gravitational pull toward each other. which statement describes the relationship between diagram x and y? gravity attracts only larger objects toward one another. gravity attracts larger objects only if they are close to one another. if the masses of the objects increase, then the force between them also increases. if distance between the objects increases, then the amount of force also increases.

What will most likely happen when two bromine atoms bond together?

Which statement is true about a catalyst? a: a catalyst decreases the rate of the reaction. b. a catalyst is consumed during a chemical reaction. c. a catalyst lowers the activation energy of a reaction. d. a catalyst increases the reactant concentration during a reaction.