Answer:
0.44 moles
Explanation:
Given that :
A mixture of water and graphite is heated to 600 K in a 1 L container. When the system comes to equilibrium it contains 0.17 mol of H2, 0.17 mol of CO, 0.74 mol of H2O, and some graphite.
The equilibrium constant ![K_c= \dfrac{[CO][H_2]}{[H_2O]}](https://tex.z-dn.net/?f=K_c%3D%20%20%5Cdfrac%7B%5BCO%5D%5BH_2%5D%7D%7B%5BH_2O%5D%7D)
The equilibrium constant 
The equilibrium constant 
Some O2 is added to the system and a spark is applied so that the H2 reacts completely with the O2.
The equation for the reaction is :

Total mole of water now = 0.74+0.17
Total mole of water now = 0.91 moles
Again:
![K_c= \dfrac{[CO][H_2]}{[H_2O]}](https://tex.z-dn.net/?f=K_c%3D%20%20%5Cdfrac%7B%5BCO%5D%5BH_2%5D%7D%7B%5BH_2O%5D%7D)
![0.03905 = \dfrac{[0.17+x][x]}{[0.91 -x]}](https://tex.z-dn.net/?f=0.03905%20%3D%20%20%5Cdfrac%7B%5B0.17%2Bx%5D%5Bx%5D%7D%7B%5B0.91%20-x%5D%7D)
0.03905(0.91 -x) = (0.17 +x)(x)
0.0355355 - 0.03905x = 0.17x + x²
0.0355355 +0.13095
x -x²
x² - 0.13095
x - 0.0355355 = 0
By using quadratic formula
x = 0.265 or x = -0.134
Going by the value with the positive integer; x = 0.265 moles
Total moles of CO in the flask when the system returns to equilibrium is :
= 0.17 + x
= 0.17 + 0.265
= 0.435 moles
=0.44 moles (to two significant figures)
The following are the statements, which indicates that the fossil record suggests about evolution on Earth:
1. Humans have only recently existed on Earth.
2. The organisms originally lived only in Earth's water.
3. The plants did not have flowers when dinosaurs existed.
The fossil remains have been discovered in the rocks of all the ages. The simplest organisms fossils are witnessed in the oldest rocks, and the fossils of more composite species are found in the newest rocks. This supports the theory of evolution suggested by Darwin, according to which the simple life forms slowly gets evolved into more composite ones.
Answer:
D
Explanation:
Organic compounds are chemical compounds which usually contains one or more atoms of carbon, hydrogen, oxygen and sometimes nitrogen or sulphur. Carbon and hydrogen are the main element that is contained in most organic compounds.
Option A is wrong because calcium phosphate is not an organic compound, although all the other compounds in the option are organic compounds.
Option B is wrong because calcium chloride is not an organic compound
Option C is wrong also as calcium sulphate is not an organic compound
Option D is correct as all are organic compounds
Answer:
C) 2 Na + 2 H2O → 2 NaOH + H2.
Explanation:
Hello there!
In this case, according to the given chemical reactions, it is possible to firstly understand that a single displacement reaction is characterized by the presence of a single element as the first reactant and a compound as the second one, thus, yielding a compound as the first product and a single element as the second one.
In such a way, according to the given choices, it possible to note that C) 2 Na + 2 H2O → 2 NaOH + H2 is the only one with the aforementioned condition as the element at the reactants side is Na and at the products side is H2.
Best regards!
Answer:
its stored in the covalent bonds