Answer:
D. They involve changes in energy.
The last one
Explanation:
have a good day
D. Magma is injected into surrounding rock forming an igneous intrusion.
Igneous intrusion forms when magma from under the surface of the earth is slowly pushed up to occupy spaces or cracks found among rocks and cools down and solidifies before it reaches the surface of the earth.
I believe the correct answer from the choices listed above is option A. A direct relationship can be represented by the expression:
y/x = k
<span>A direct relationship is an expression between two numbers or other variables where an increase or decrease in one variable causes the same change in the other value.</span>
Answer:
4 Fe + 3 O2 = 2 Fe2O3
Explanation:
In order to balance the equation, there should be equal number of iron atoms (Fe) and oxygen atoms (O2) in Iron(III) oxide (Fe2O3).
Since there are two atoms of Oxygen in 1 oxygen molecule and 3 atoms of Oxygen in 1 Iron Oxide, the least common multiples of the total oxygen atoms which would equal each other is 6 atoms of Oxygen. This results in 3 molecules of O2 and 2 molecules of Fe2O3.
In order to balance out the amount of iron in iron oxide, you must then calculate the total iron atoms in iron oxide; since there are 2 atoms of Fe in each molecule of Iron Oxide and there is 2 molecules of Fe2O3, the total is 2*2 = 4 atoms of iron, Fe.
In order to get 4 atoms of iron from molecules of Fe, you need 4 molecules of Fe, since each molecule contains 1 Fe.
Answer: (A) 
(B) 
Explanation:
(A) As we know that HCl is a strong acid and when it is added to an aqueous solution then it leads to increase in the concentration of hydrogen ions. And, when an acid or base is added to a solution then any resistance by the solution in changing the pH of the solution is known as a buffer.
This means that addition of buffer into the given solution will not cause much change in the concentration of 
in large amount.
As both the buffer components are salt then they will remain dissociated as follows.
Hence, net ionic equation will be as follows.
(B) When we add small amount of sodium hydroxide into the solution then there will occur an increase in concentration of hydroxide ions into the solution. But then due to the presence of buffer there will occur not much change in concentration and the acid will get converted into salt.
The net ionic equation is as follows.
