Answer:
Explanation:
Given :
Mass of a bar of lead = 115.2 g
Initial water level 
= 25 mL
Final water level = 35.5 mL
Difference in the water level = 35.5 - 25
= 10.5 mL
= 
We know that when a body is submerged in water, it displaces its own volume of water.
Therefore, the volume of the lead bar = volume of the water displaced = 10.5 mL =
We know that mathematically, density is the ratio of mass of body to its volume.
Density of the lead bar is given by :
=
Explanation:
As per the Hess’s law of constant heat summation, the heat absorbed or evolved in a given chemical equation is the same whether the process occurs in one step or several steps.
Hence, according to this law the chemical equation can be treated as ordinary algebraic expression and can be added or subtracted to yield the required equation. This means that the enthalpy change of the overall reaction is the sum of the enthalpy changes of the intermediate reactions.
..........(1)
..............(2)
The final reaction is as follows:
.............(3)
Therefore, adding (1) and (2) we get the final equation (3) and value of 
at 298 K will be as follows.
= 
+ 
= -314 kJ + (-80) kJ
= -394 kJ
Thus, we can conclude that 
at 298 K for the given process is -394 kJ.
Answer: 106.905
Explanation: If there are only 2 isotopes, and 1 of them is 48.16%, the second must, by default, be (100 - 48.16%) = 51.84% The final, averaged, atomic mass is 107.868. This is made up of each isotope's atomic mass times the percentage of that isotope in the total sample. The weighted value of the known isotope (109) plus that of the unknown must come to the observed value of 107.868 amu. (107.868 - 52.45 = 55.42). Divide that by the % for that isotope (55.42/0.5184) = 106.90 amu for the second isotope.
<u>Atomic Mass</u> <u>% of Sample</u> <u>Weighted Value</u>
108.905 48.16% 52.45
X 51.84% <u>55.42</u>
107.87
X = (55.42/0.5184) = 106.90 amu
Temperature. In case you have ever baked, you can relate to this. For example, when you make caramel, you simply put the caramel on a boiling hot pan and sit back and watch it. It always goes fastest this way.
0.500 grams would be left after 56.0 days.
After 14 days=4.00 g
After 28 days=2.00 g
After 42 days=1.00 g
After 56 days=0.500 g
This is after four half lives.
