Answer:
Are basic:
[OH⁻] = 3.13x10⁻⁷M and [H₃O⁺] = 9.55x10⁻⁹M
Explanation:
A solution is basic when pH = - log [H₃O⁺] is higher than 7.
It is possible to convert [OH⁻] to [H₃O⁺] using:
[H₃O⁺] = 1x10⁻¹⁴ / [OH⁻]
a. [OH⁻] = 3.13x10⁻⁷M
[H₃O⁺] = 1x10⁻¹⁴ / [3.13x10⁻⁷M]
[H₃O⁺] = 3.19x10⁻⁸M
pH = - log [H₃O⁺] = 7.50
[OH⁻] = 3.13x10⁻⁷M is basic
b. pH = -log [H₃O⁺] = - log 0.000747M = 3.13.
This solution is not basic
c. [H₃O⁺] = 9.55x10⁻⁹M
pH = 8.02
This solution is also basic.
There are several ways to give an object potential energy. One can move the object against the force of gravity to increase. One can also stretch an object out or put pressure on it.
Mixtures are of 2 types.
1) Homogeneous mixture : In this type of mixture, the components of the mixture are present in the same phase. For example, Air. Air is a mixture of different gases which cannot be distinguished from each other.
2) Heterogeneous mixture : In this type pf mixture, 2 or more phases can be seen. The composition of the different components is not the same throughout the mixture.
Ex. mixture of oil and water. Here we can see 2 different phases one consisting of oil layer and the other made of water layer.
Salt water is a mixture of salt and water. Since salt is completely soluble in water, it creates a homogeneous mixture when mixed with water. We cannot distinguish salt and water once they are mixed.
To get fresh water from the salt water in the ocean, we can set up a simple distillation unit . In this, the salt water is heated to its boiling point and the vapors thus formed are allowed to cool which condense and create liquid water. This can be used as fresh water.
The reaction for the formation of MgO(s):
2 Mg (s) + O2(g) -à
2MgO(s) ΔH = -601.24
kJ/mol
<span>The enthalpy
information is taken from: http://webbook.nist.gov/cgi/inchi?ID=C1309484&Mask=2</span>
From the equation and with an enthalpy change of -231 kJ:
-231 kJ * 2 mol Mg * (1/-601.24 kJ/mol) = 0.76841 mol Mg
Then, with the molar mass of MgO = 40.3,
0.76841 mol Mg *(2 mol MgO/2 mol Mg)* 40.3 g/mol MgO = <span>30.967 g MgO</span>