3. Other names for S- waves are secondary waves, shear waves, and sometimes elastic S-waves. Other names for P-waves are primary waves and compressional waves.
4. You need 3 stations, because scientists find the difference between the arrival times of the primary and the secondary waves at each of the 3 stations, then the time difference is used to determine the distance of the epicentre from each station. The greater the difference in time, the further away the epicentre is. A circle is drawn around each station, with a radius corresponding to the epicentre’s distance from that station. The point where the three circles meet is the epicentre. If you only had two stations, you could only predict the epicentre, as the point where all three circles meet wouldn’t be complete, you’d have to try and estimate where the third one would intercept. This would greaten the chance of error and isn’t as accurate.
Hope this helps!
Answer: 44.8 L
Explanation:
According to avogadro's law, 1 mole of every substance occupies 22.4 L at STP and contains avogadro's number 
of particles.
Standard condition of temperature (STP) is 273 K and atmospheric pressure is 1 atm respectively.
To calculate the moles, we use the equation:
1 mole of 
occupies volume = 22.4L at STP
Thus 2 moles of magnesium react with=
Thus the volume of 
molecules of nitric oxide gas is 44.8 L.
Calories heat added = Mass of glass times temp. increase times specific heat of glass
calories (small calories) = l.0 g x 20 degrees x .16 calories/gm/degree C = 3.2 calories
Sulfur reacts with oxygen to yield SO3 as shown in the equation below;
2S(g)+ 3O2(g) = 2SO3(g)
From part A 7.49 g of S were used.
The atomic mass of sulfur is 32.06 g/mol
Hence, the number of moles of sulfur used
7.49 / 32.06 = 0.2336 moles
The mole ratio of S : SO3 is 1:1
Thus the mass of SO3 will be ( 1 mol of SO3= 80.06 g)
0.2336 moles × 80.06 = 18.7 g
