Answer:
Potential energy = 441 N
Explanation:
Given:
Mass M = 15 kg
Height = 3 m
Find:
Potential energy
Computation:
Potential energy = mgh
Potential energy = (15)(9.8)(3)
Potential energy = 441 N
Answer:
The final temperature at 1050 mmHg is 134.57
or 407.57 Kelvin.
Explanation:
Initial temperature = T = 55
= 328 K
Initial pressure = P = 845 mmHg
Assuming final to be temperature to be T' Kelvin
Final Pressure = P' = 1050 mmHg
The final temperature is obtained by following relation at constant volume

The final temperature is 407.57 K
Answer:
Single Replacement; 2, 1, 1, 1
Explanation:
2HCl + Zn → H2 + ZnCl2
In a single replacement reaction, one specie is replaced by another specie in a chemical reaction.
If we look at the reaction above, zinc metal reacted with hydrochloric acid. The reaction proceeds in such a manner that zinc replaces hydrogen in hydrochloric acid. This is a single replacement reaction because only one chemical specie is displaced in the reaction.
Answer:
a. positive
b. negative
c. positive
d. negative
Explanation:
In a exothermic reaction, heat is written as a product (del H is negative), whereas in an endothermic reaction heat is written on the reaction side (del H is positive).
For a, it is endothermic process. We know this because to go from solid to liquid you need to put energy into the system. When we put energy into a chemical system it is said to be an endothermic reaction.
For b, it is exothermic reaction. This is because you have to lose the extra energy to go from less ordered states (gas) to more ordered state (liquid). Gas is less ordered because its molecules are freely moving and such. Another way of thinking about this question is just putting the heat on product side and think if I was going in reverse direction I would put heat in product because I would need to add heat to liquid to turn to gas (and if heat is added to product side we know its exothermic). Two ways of thinking whichever you prefer.
The rest have similar explaination.
The idea behind a tree diagram is to start on the left with the whole thing, or one. Every time several possible outcomes exist the probability in that branch splits off into a smaller branch for each outcome.