Calculate the molality of a 35.4% (by mass) aqueous solution of phosphoric acid, H3PO4 (molar mass = 98 g/mol).​

The answer for #3 is c but i don't know why

Check the correct box to describe the periodic trends in electronegativity. electronegativity across a period: decreases. increases. electronegativity down a group: decreases. increases.

Water (2510 g ) is heated until it just begins to boil. if the water absorbs 5.09×105 j of heat in the process, what was the initial temperature of the water?