Using deep-sea sediment cores found that Milankovitch cycles correspond with periods of major climate change over the past 450,000 years, with Ice Ages occurring when Earth was undergoing different stages of orbital variation.
Fixed vs Variable Oxidation is given below.
Explanation:
1.In its compounds, hydrogen has an oxidation number of +1, except. hydrides where the. oxidation number of hydrogen is -1. In their compounds, the metals with fixed oxidation states have the oxidation number that. corresponds with the fixed oxidation number.
A variable oxidation state is a value that determines the charge of the atom depending on certain conditions.
2. Oxidation state of elements is considered to be of the most important in the study of chemistry. For some elements, this figure is constant known as fixed oxidation , while for others it is variable is called variable oxidation state.
3. MgCl2 : magnesium is in Group IIA and all elements in Group IIA have fixed oxidation numbers of +2
FeCl2 : iron has a variable oxidation number of either +2 or +3 and is not fixed
Forces affect how objects move. They may cause motion; they may also slow, stop, or change the direction of motion of an object that is already moving. Since force cause changes in the speed or direction of an object, we can say that forces cause changes in velocity. Remember that acceleration is a change in velocity. Let’s say an object is moving along a table on earth, suddenly the finite table ends, resulting in the object being present in the air, which means there is no normal contact force N to combat the force by gravity mg, which is why there is an acceleration downwards. This proves as a projectile motion since the direction of motion start changing from horizontal to vertical. Another example is one throwing an object up. It moves up and slows down, reaching its maximum point, leading to it starting to move downwards. This too is a change in motion.
Answer: Moles of hydrogen required are 4.57 moles to make 146.6 grams of methane, 
.
Explanation:
Given: Mass of methane = 146.6 g
As moles is the mass of a substance divided by its molar mass. So, moles of methane (molar mass = 16.04 g/mol) are calculated as follows.
The given reaction equation is as follows.
This shows that 2 moles of hydrogen gives 1 mole of methane. Hence, moles of hydrogen required to form 9.14 moles of methane is as follows.
Thus, we can conclude that moles of hydrogen required are 4.57 moles to make 146.6 grams of methane, .
