1.- A solution is prepared by mixing 45 grams of NaCl with 135 grams of water. a) Determine the% mass / mass of the solution DATA:
Solute:
Solvent:
Solution:

b) How many grams of NaCl are in 890 g of solution?

2.- Caffeine is an organic compound of the alkaloid family and we can find it in coffee and tea, among other plants. A coffee maker indicates on the product label than in one serving (one teaspoon) of dough 1.8 g of hay 0.07 g of caffeine. What is the percentage by mass of caffeine in soluble coffee?
DATA:
Solute:
Solvent:
Solution:

Answer asap need 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.