Chemistry
If you have a list of acids or bases and their conjugate salts, and are asked which pairs create the best buffer, how would you know which are best?
chemistry
We're studying acids and bases; the question states that 50mL of 0.1M HNO3 solution is mixed with 25mL of 0.1M NaOH. What is the pH? I thought that I would use the Henderson-Hasselbach equation; but my answer does not match the one give in the solution. Any help?
CHEMISTRY
I am struggling with organizing stoichiometry problems; I know how to solve them after they're set up. Here is an example: "An organic compound with a FW of 417 was analyzed for ethoxyl {CH3-CH2O-} groups with the rxn: ROCH2CH3 + HI --> ROH +CH3CH2I CH3CH2I + Ag + ...
Physics
Two point charges lie on the x axis. A charge of + 6.5 µC is at the origin, and a charge of -1.5 µC is at x = 10.0 cm. What is the net electric field at x = -2.0 cm? I found the electrical field for each charge using the equation E= k(q)/ r^2. My calculations were:...
physics
At a recent rock concert, a dB meter registered 112 dB when placed 1.70 m in front of a loudspeaker on the stage. (a) What was the power output of the speaker, assuming a hemispherical radiation of the sound and neglecting absorption in the air? (b) How far away would the inte...
physics
A 64.0 kg person stands on a lightweight diving board supported by two pillars, one at the end of the board, the other 1.20 m away from the end. The pillar at the end of the board exerts a downward force of 829 N. How far from the pillar at the end of the board is the person s...
Physics
A neutron collides elastically with a helium nucleus (at rest initially) whose mass is four times that of the neutron. The helium nucleus is observed to rebound at an angle '2 = 41° from the neutron's initial direction. The neutron's initial speed is 5.6 105 m/...
physics
An explosion breaks an object into two pieces, one of which has 3.20 times the mass of the other. If 8000 J were released in the explosion, how much kinetic energy did each piece acquire? I started with using KE = (1/2)mv^2 and m1v1 = m2v2. Then (1/2)m1(v1)^2 + (1/2)m2(v2)^2 =...
physics
A 85 kg trampoline artist jumps vertically upward from the top of a platform with a speed of 3.5 m/s. How fast is he going as he lands on the trampoline, 3.0 m below? If the trampoline behaves like a spring of spring constant 5.2 x 10^4 N/m, how far does he depress it? My prof...
physics
A person is to be released from rest on a swing pulled away from the vertical by an angle of 15.8°. The two frayed ropes of the swing are 2.75 m long, and will break if the tension in either of them exceeds 350 N. What is the maximum weight the person can have and not brea...
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