Problem One (left)
This is just a straight mc deltaT question
<em><u>Givens</u></em>
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
Answer: 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.
Answer: 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.
Answer: 0.25
Answer C
M1V1 = M2V2
(2.50)(100.0) = (0.550)V2
V2 = 455mL
You can make 455mL of 0.550M solution from 100.0mL of 2.50M solution.
<u>Answer:</u>
<em>The sign of work for this process will be Negative.</em>
<em></em>
<u>Explanation:</u>
Work done by the system on the surroundings is negative
So, If work is done on the system, its sign is positive. If work is done by the system, its sign is negative
Here we see the system that is argon gas is expanding and the work is done by the system into the surroundings (vessel) and the sign is Negative
Therefore, the sign of work for this process will be Negative.
Answer:
C. pieces of hair found at the crime scene.
Explanation:
using the pieces of hair, you can get the DNA of the person. This will give u a better lead in solving the crime.
Hope it helps u ....
Answer:
1.65 A
Explanation:
The hydrogen gas dissociates following the equation:
H₂(g) → 2H⁺ + 2e⁻
So, for 1 mol of H₂, 2 moles of electrons are given. The current is formed because of the presence of the electrons. Thus, the number of moles of electrons is the double of the moles of hydrogen gas: 1.026x10⁻³ mol.
By the Faraday law, 1 mol of electrons produces 96500 C of charge, thus:
1 mol --------------- 96500 C
1.026x10⁻³ mol ---- x
By a simple direct three rule:
x = 99.009 C
The current is the charge divided by the time. So, for 1 min = 60 s,
i = 99.009/60
i = 1.65 A
