Option c. dendrochronology
tree rings or dendrochronology they allow to use it in calibration for carbon-14 on temporal placements of fragments of wood (from long dead trees).
Example Bristle cone pines (1957) 4723 years old
Answer:
M = 0.050 M
Explanation:
WE have an acid base reaction between NaOH and HCl. The reaction is as follow:
HCl + NaOH -------> NaCl + H₂O
As we can see, we have a balanced equation already, and we can also see that the mole ratio between the HCl and NaOH is 1:1, therefore we can use the following expression:
M₁V₁ = M₂V₂ 1: acid; 2: base
This expression is used when the reactions has reached the equivalence point. As we want to know the concentration of the base, we just solve for M₂ above so:
M₂ = M₁V₁ / V₂
All we have to do now is replace the given values and solve for the concentration:
M₂ = 0.15 * 27 / 81
<h2>
M₂ = 0.050 M</h2><h2>
This is the concentration of the base</h2>
Answer:
It is less dense than oxygen gas.
Explanation:
Density is a physical property. Reactivity, flammability, and acid compounds are all chemical properties.
Hope that helps.
The correct answer is D:
it involves breaking molecular bonds between copper compounds
.
The explanation :
-when we melt a copper it is a physical change because the substance is still copper and have the same shape.
- but for example Burning a copper it is a chemical change. Fire activates a chemical reaction between copper and oxygen.
-The oxygen in the air reacts with the copper and the chemical bonds are broken.
- the chemical change is changing the other compound bonded to the copper atoms.
So, the correct answer is D
The problem ask to show the reaction between the two elements which is calcium and oxygen to form an ionic compound. Base on the data that Calcium has n electronic compound of 2.8.8.2 and oxygen has 2.6, the reaction of the both is to add 2 electron in Calcium and also in the oxygen because both of the m has 2 extra electron
