40pionts
a blacksmith making a tool heats 525 grams of steel to 1230°c. after hammering the steel, she places it into a bucket of water to cool it. when she removes the steel from the water, it’s at 50°c. how much heat does the steel release if its specific heat capacity is 0.486 joules/gram degree celsius?

Problem One (left)

This is just a straight mc deltaT question

Givens

m = 535 grams

c = 0.486 J/gm

tf = 50

ti = 1230

Formula

E = m * c * (ti - tf)

Solution

E = 535 * 0.486 * ( 1230 - 50)

E = 535 * 0.486 * (1180)

E = 301077

A

Problem Two

This one just requires that you multiply the two numbers together and cut it down to 3 sig digits.

E = H m

H = 2257 J/gram

m = 11.2 grams

E = 2257 * 11.2

E = 25278  to three digits is 25300 Joules. Anyway it is the last one.

Three

D and E are both incorrect for the same reason. The sun and stars don't contain an awful lot of Uranium (1 part of a trillion hydrogen atoms). It's too rare. The other answers can all be eliminated because U 235 is pretty stable in its natural state. It has a high activation complex.

Your best chance would be enriched Uranium (which is another way of saying refined uranium). That would be the right environment. Atomic weapons and nuclear power plants (most) used enriched Uranium. You can google "Little Boy" if you want to know more.

B

Four

The best way to think about this question is just to get the answer. Answer C.

A: incorrect. Anything sticking together implies a larger and larger result. Gases don't work that way. They move about randomly.

B: Wrong. Heat and Temperature especially depend on movement. Stopping is not permitted. If a substance's molecules stopped, the substance would experience an extremely uncomfortable temperature drop.

C: is correct because the molecules neither stop nor do they stick. The hit and move on.

D: Wrong. An ax splitting something? That is not what happens normally and not with ordinary gases. It takes more energy that mere collisions or normal temperatures would provide to get a gas to split apart.

E: Wrong. Same sort of comment as D. Splitting is not the way these things work. They bounce away as in C.

Five

Half life number 1 would leave 0.5 grams behind.

Half life number 2 would leave 1/2 of 1/2 or 1/4 of the number of grams left.

0.25

Answer C

vanderwaal's forces of attraction are the electrostatic intermolecular forces that exist in a molecule due to the temporary or permanent dipoles that are developed in a molecule. in , the major intermolecular forces are dipole-dipole interactions as the molecule is polar (bent structure). so the vanderwaal's forces of interaction in between molecules are the permanent dipole-dipole interactions that develop due to the dipole that exists in between the polar h - s bond. the positively charged hydrogen atom is attracted towards the negative end of the dipole that is sulfur of the adjacent molecule. therefore, these forces of attraction are relatively stronger than that of london dispersion forces that exist in non polar molecules.