According to the cooling curve given above, at temperature 275K, the phases that will be observed is LIQUID AND SOLID.
The flat points on the graph represent the points where phase changes are taking place.The beginning of the first flat point represent the point where the gas become liquid, the extreme end of this point indicate the point where the liquid has started turning to liquid and that is the point of 275K. Thus at that point both phases are present.
A pure substance, only one type of atom
Answer:

Explanation:
We can convert the formula units to moles and then use the molar mass to find the mass.
1. Moles of Pb(MnO₄)₂

2. Mass of Pb(MnO₄)₂

Bond energy refers to the energy that must be taken in to break a bond. It is also the energy required to form the bond.
<h3>What is Bond energy?</h3>
The term bond energy refers to the energy that must be taken in to break a bond. It is also the energy required to form the bond.
The energy that must be supplied to break the bonds in two molecules of HCl is 862 J. The energy released is obtained from; 862J - [436 +262] = 164J.
The total energy of the reaction is 164J, this is called the enthalpy change. Based on this value of the total energy, the reaction is endothermic. Hence, it is true that; "It takes more energy to break the two H–Cl bonds than is released when forming the H–H and Cl–Cl bonds."
Learn more about bond energy:brainly.com/question/16754172?
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Answer:
Element.
General Formulas and Concepts:
<u>Chemistry</u>
- Reading a Periodic Table
- Diatomic Elements
Explanation:
Diatomic Elements are elements that are bonded to themselves. Naturally, these elements are not found alone in nature.
Diatomic Elements:
Hydrogen
Nitrogen
Oxygen
Fluorine
Chlorine
Bromine
Iodine
Since Nitrogen is a diatomic element, we would find Nitrogen in nature as N₂.