If 2.8x10 to the 5th power j of heat are added to a sample of water and it’s temperature changes from 63.5 degrees to 78.5 degrees Celsius, then what is the mass of the water

Compare and contrast physical changes with chemical changes.

Answer asap need to be answered by wednesday morning explain how a buffer works, using an ethanoic acid / sodium ethanoate system including how the system resists changes in ph upon addition of a small amount of base and upon addition of a small amount of acid respectively. include the following calculations in your i. calculate the ph of a solution made by mixing 25cm3 0.1m ch3cooh and 40cm3 0.1m ch3coo-na+. [ka = 1.74 x 10-5 m] ii. calculate the ph following the addition of a 10cm3 portion of 0.08 m naoh to 500cm3 of this buffer solution. iii. calculate the ph following the addition of a 10cm3 portion of 0.08 m hcl to 200cm3 of the original buffer solution.

Acandle’s wick is the fabric string that holds the flame, and it burns down at a constant slow pace when the candle is lit. the wick is usually surrounded by wax. which is the most important property of covalent compounds that makes them useful for making candle wax? a low boiling point a low melting point a high boiling point a high melting point