most events like the rising and setting of the Sun were used a natural measurement of time until recently.
Solar time, which is based on the motion of the Sun, is not the only way of measuring time, however. One might keep track of the regular appearance of the full Moon. That event occurs once about every 29.5 solar days. The time between appearances of new moons, then, could be used to define a month.
One also can use the position of the stars for measuring time. The system is the same as that used for the Sun, since the Sun itself is a star. All other stars also rise and set on a regular basis.
Although any one of these systems is a satisfactory method for measuring some unit of time, such as a day or a month, the systems may conflict with each other. It is not possible, for example, to fit 365 solar days into 12 or 13 lunar months exactly. This problem creates the need for leap years
Read more: http://www.scienceclarified.com/Ti-Vi/Time.html#ixzz5e1E705sr
I abbreviated most of it but there is a ton more at this link if you still need more.
Answer:
The oxidation state of N in the KNO3 is +5
Explanation:
Oxidation rules:
1. Oxygen is -2, unless in peroxides.
2. Group 1 metals = +1
3. Group 2 metals = +2
4. If the molecule is neutral, all of the oxidation numbers have to add up to zero.
5. If the molecule is charged, all of the oxidation numbers have to add up to the charge of the molecule.
So, the given formula represents the salt compound formula unit of potassium nitrate: KNO3
The formula unit is uncharged.
From our rules, we know that,
O = -2
And we can find K on the periodic table, in the first group, thus giving it a +1 charge. Now let's put it all together.
K = +1
N = x
O = -2
Let's take into account the number of atoms of each element we have and make an equation since we know everything has to add up to zero since the molecules are neutral.
+1 +x+3 (-2) = 0 (notice we multiplied 3 by -2 because in the formula we have 3 atoms of oxygen with -2 charge each)
x - 5 = 0
x = 5
Therefore, the oxidation number of N in KNO3 is +5.
Answer:
19.79%
Explanation:
mass % = (mass solute / total mass) * 100
total mass = 129.54 + 525 = 654.54
solute = C6H12O6
(129.54/654.54) = .1979
.1979 * 100 = 19.79%
No it depends on the molecules strength
