Answer:
a. The student's mistake was that the student did not swing the pendulum and start the watch at the same time.
b. 1.2 s per swing.
c. The likely effect of her reaction time is that they will should subtract two seconds off the time.
Explanation:
I'm going to answer this by using rounded numbers for the atomic masses. You need only go back and put the numbers in from your periodic table. My answers will be close, but not what you should get.
Find the Molar Mass of MgCl2
Mg = 24 grams
2Cl = 2 * 35.5 = 71 grams
Total = 95 grams
Find the mols in 339 grams
1 mole = 95 grams
x mol = 339
Solve
339 = 95x Divide by 95
339/95 = x
x = 3.67 mols Answer
Kinetic Energy = (1/2) mv^2.
m = 57.7 g = 57.7/1000 = 0.00577 kg.
v = 325 m/s.
E = 0.5 * 0.00577 * 325^ 2. Use your calculator.
E = 304.728125 J.
That's the kinetic energy.
Im guessing it's (a) since the numbers go in chronological order and you read the periodic table left to right
