Covalent bond a chemical bond formed by two electrons that are shared between two atoms
ionic bond<span> a chemical bond formed by the electrostatic attraction between ions</span>
metallic bond<span> a bond characteristic of metals in which mobile valence electrons are shared among positive nuclei in the metallic crystal</span>
Answer:
-100 kJ
Explanation:
We can solve this problem by applying the first law of thermodynamics, which states that:

where:
is the change in internal energy of a system
Q is the heat absorbed/released by the system (it is positive if absorbed by the system, negative if released by the system)
W is the work done by the system (it is positive if done by the system, negative if done on the system)
For the system in this problem we have:
W = +147 kJ is the work done by the system
Q = +47 kJ is the heat absorbed by the system
So , its change in internal energy is:

Answer:
4121 years
Explanation:
From;
0.693/t1/2 = 2.303/t log No/N
t1/2= half life of the carbon-14
No= count rate of the living tissue
N= count rate of the sample
t = age of the sample
0.693/5730 =2.303/t log (13.5/8.2)
1.21 * 10^-4 = 2.303/t * 0.2165
1.21 * 10^-4 = 0.4986/t
t = 0.4986/1.21 * 10^-4
t = 4121 years
Answer : The temperature in degree Celsius is, 
Explanation :
The conversion used for the temperature from Kelvin to degree Celsius is:

where,
= temperature in Kelvin
= temperature in centigrade
As we are given the temperature in Kelvin is, 2.7
Now we have to determine the temperature in Kelvin.



Therefore, the temperature in degree Celsius is, 
Answer:
16.0%.
Explanation:
Volume percent of a substance is the ratio of the substance volume to the solution volume multiplied by 100.
V % of ethanol = (volume of ethanol / volume of the solution) x 100.
volume of ethanol = 90.0 mL, volume of the solution = 550.0 mL.
∴ V % of ethanol = (90.0 mL / 550.0 mL) x 100 = 16.36% ≅ 16.0%.