The property of liquid oxygen that makes it especially difficult and potentially harmful to work with at home would be its cryogenic temperature. Liquid oxygen is being produced from the compression of oxygen gas to -196 degrees Celsius. As you can see, it has a very cold temperature that is why it used in cryogenics. Although liquid oxygen is non-toxic to humans, it would cause burns that are severe when being touched. Also, it would make certain materials brittle and unstable. Another property that makes it dangerous for use at home would be that it is very flammable. Proper handling is a must for this substance.
Non-volatile solutes such as salt raises the boiling point of water. Hope the answer helps! Good luck!
Answer:
Excited state
Explanation:
Excited state is the name of the state when electrons absorb energy and move to a higher energy level.
Hope this helps!
Answer:
The molar concentration of Cu²⁺ in the initial solution is 6.964x10⁻⁴ M.
Explanation:
The first step to solving this problem is calculating the number of moles of Cu(NO₃)₂ added to the solution:

n = 1.375x10⁻⁵ mol
The second step is relating the number of moles to the signal. We know the the n calculated before is equivalent to a signal increase of 19.9 units (45.1-25.2):
1.375x10⁻⁵ mol _________ 19.9 units
x _________ 25.2 units
x = 1.741x10⁻⁵mol
Finally, we can calculate the Cu²⁺ concentration :
C = 1.741x10⁻⁵mol / 0.025 L
C = 6.964x10⁻⁴ M
Answer : The final temperature of the copper is, 
Solution :
Formula used :

where,
Q = heat gained = 299 cal
m = mass of copper = 52 g
c = specific heat of copper =
= final temperature = ?
= initial temperature = 
Now put all the given values in the above formula, we get the final temperature of copper.


Therefore, the final temperature of the copper is, 