Answer:
The net change in enthalpy for the formation of one mole of acrylic acid from calcium carbide, water and carbon dioxide is -470.4 kJ/mol.
Explanation:
Step 1 : Calcium carbide and water react to form acetylene and calcium hydroxide
..[1]
Step 2 : Acetylene, carbon dioxide and water react to form acrylic acid
..[2]
Using Hess's law:
[1] × 6 + [2]
The energy released on formation of 5 moles of acrylic acid = -2352 kJ
The energy released on formation of 1 moles of acrylic acid :
Hence, the net change in enthalpy for the formation of one mole of acrylic acid from calcium carbide, water and carbon dioxide is -470.4 kJ/mol.
I think the answer would be b because your throat is reacting to the cough?
1) You need to use the atomic mass of copper.
You can find it in a periodic table. It is 63.546 amu.
2) The atomic mass is the weigthed mass of the different isotopes.
This is, the atomic mass of one element is the atomic mass of each isotope times its corresponding abundance:
=> atomic mass of the element = abundance isotope 1 * atomic mass isotope 1 + abundance isotope 2 * atomic mass isotope 2 + ....+abundance isotope n * atomic mass isotope n.
3) The statement tells there are two isotopes so the abundance of one is x and the abundance of the other is 1 - x
=> 63.546 amu = x * 62.9296 amu + (1-x)*64.9278
=> 63.546 = 62.9296x + 64.9278 - 64.9278x
=> 64.9278x - 62.9296 = 64.9278 - 63.546
=> 1.9982x = 1.3818
=> x = 1.3818 / 1.9982 = 0.6915 = 69.15%
=> 1 - x = 1 - 0.6915 = 0.3085 = 30.85%
Answer:
Cu-63 69.15%;
Cu-65 : 30.85%
A carbon-12 atom has 6 protons (6P) and 6 neutrons (6N). But some types of carbon have more than six neutrons. We call forms of elements that have a different number of neutrons, isotopes. For example, carbon-14 is a radioactive isotope of carbon that has six protons and eight neutrons in its nucleus.
Hope that helps
