Chemical compounds

a.
are always made up of one type of element and one type of atom.

b.
can be made up of a combination of different elements.

c.
are always made up of several atoms with the same number of protons.

d.
can be made up of one atom with several different elements in it.

Air initially at 0.75 bar, 1000 k, and occupying a volume of 0.12 m^3 undergoes two processes. process 1-2: the air is compressed isothermally until the volume is halved. process 2-3: the air undergoes a constant pressure process until the volume is halved again. assume ideal gas behavior. a) determine the mass of the air, in kg. b) the work and the heat transfer for each of the two processes, in kj. (100 kj = 1 bar . m^3)

The base of a 50-meter tower is at the origin; the base of a 50-meter tree is at (0, 50, 0). the ground is flat and the z-axis points upward. the following parametric equations describe the motion of six projectiles each launched at time t = 0 in seconds. (i) r (t) = (50 + t2)k (ii) r (t) = 2t2 j + 2t2k (iii) r (t) = 50 i + 50 j + (50 − t2)k (iv) r (t) = 2t j + (50 − t2)k (v) r (t) = (50 − 2t) i + 2t j + (50 − t)k (vi) r (t) = t i + t j + tk (a) which projectile is launched from the top of the tower and goes downward? at time t = , the projectile hits the ground at point (x, y, z) = . (b) which projectile hits the top of the tree?

To find the mass defect for uranium-238 several calculations must be made. which is the calculation that should be made first? assume atomic number for uranium-238 is 92. a. 92(1.0073) x 92(1.0087) = b. 92(1.0073) x 146(1.0087) = c. 146(1.0073) x 238(1.0087) = d. 238(1.0073) x 238(1.0087) =