The naturally occurring isotopes of Li are Li-6 of mass 6.015121 amu and Li-7 of mass 7.016003 amu. The atomic mass of Li is 6.9409 amu, the percent abundance can be calculated using the following relation.
Atomic mass=m(Li-6 )×%(Li-6 )+m(Li-7 )×%(Li-7 )
Let the percent abundance of Li-6 be X thus, that of Li-7 will be 1-X, putting the values,

Or,

Or,
X=0.075
Thus, 
Thus, percent abundance of Li-6 is 0.075 or 7.5 % and that of Li-7 is 0.925 or 92.5%.
The wood is using the oxygen for fuel
Answer:
Heat transfer in the atmosphere from the equatorial regions to higher latitudes occurs through the process of Convection
Explanation:
The equatorial regions of the earth's surface receive the most heat from the sun than any other region of the earth. This is because the are most directly in line with the direct heat from the sun.
Due to this heat from the sun, atmospheric air around the equatorial regions are hot and less dense than air in regions of higher latitudes, and thus, rises above the equator. The rising air at the equator is replaced by colder and denser air from higher latitudes north and south of the equator. As the rising air of the equatorial regions are being replaced by colder and denser air from higher latitudes, the hot and humid air moves away from the equator, toward regions of higher latitude, north and south thereby setting up a convection current of heat flow.
Phase of matter
Explanation:
The phase of matter strictly is a function of its temperature. Matter exists in different phases at different temperatures.
- Matter is anything that has weight and occupies space.
- There are three states of matter:
- Solid
- Liquid
- Gas
These phases of matter depends on temperature.
For example;
- Water exists as gases above boiling point
- Water is also solid at freezing point.
- Between the freezing and boiling point, water is a liquid.
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