A sample of what was thought to be gold was removed from a mine in San Francisco during the gold rush. After analysis, it was determined that it was actually fool's gold, or pyrite. The sample. contained 17.6 grams of iron and 10.3 grams of sulfur. What is the percentage composition of each element in pyrite?

Which of the following is a testable hypothesis? a. if i brush my teeth, i will get fewer cavities than if i don't brush my teeth. b. green toothpaste tastes better than blue toothpaste or red toothpaste. c. smart, careful, healthy people always brush their teeth. d. it's wrong to not brush your teeth before you have an important conversation with someone.

Ammonia and oxygen react to form nitrogen monoxide and water, like this: 4nh3 (g) + 5o2 (g) → 4no (g) + 6h2o (g) also, a chemist finds that at a certain temperature the equilibrium mixture of ammonia, oxygen, nitrogen monoxide, and water has the following composition: compound pressure at equilibrium nh3 65.1atm o2 31.3atm no 62.7atm h2o 65.8atm compound pressure at equilibrium nh3 65.3 atm o2 7.79 atm no 12.1 atm h2o 65.8 atm calculate the value of the equilibrium constant kp for this reaction. round your answer to 2 significant

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.