Atom is the
most basic unit of matter. They are the general term used to describe pieces of
matter. But a different kind of atom makes up an element. A combination of atom of different elements
creates a molecule. For example, you have water; it has a chemical formula of
H2O. If you separate H from O, you have two atoms. Two atoms for hydrogen and
one atom for oxygen. However, they are of different elements. And when you
combine them to form H2O, you create a molecule.
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You have to use density=mass/volume formula:

Solve for x and you get
2282.75 grams
26 elements are man-made ..........
Seven diatomic elements are H₂, Cl₂, N₂, F₂, Br₂, I₂ and O₂.
<h3>Which are diatomic molecules?</h3>
Diatomic molecules are those molecules in which two atoms of same elements are present, and they are combined to attain the stability.
The seven diatomic molecules which are exist in the chemistry are:
- Hydrogen gas (H₂)
- Chlorine gas (Cl₂)
- Nitrogen gas (N₂)
- Fluorine gas (F₂)
- Bromine gas (Br₂)
- Iodine gas (I₂)
- Oxygen gas (O₂)
Hence H₂, Cl₂, N₂, F₂, Br₂, I₂ and O₂ are 7 diatomic molecules.
To know more about diatomic molecules, visit the below link:
brainly.com/question/14466404
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Answer:
This reaction is exothermic because the system shifted to the left on heating.
Explanation:
2NO₂ (g) ⇌ N₂O₄(g)
Reactant => NO₂ (dark brown in color)
Product => N₂O₄ (colorless)
From the question given above, we were told that when the reaction at equilibrium was moved from room temperature to a higher temperature, the mixture turned dark brown in color.
This simply means that the reaction does not like heat. Hence the reaction is exothermic reaction.
Also, we can see that when the temperature was increased, the reaction turned dark brown in color indicating that the increase in the temperature favors the backward reaction (i.e the equilibrium shift to the left) as NO₂ which is the reactant is dark brown in color. This again indicates that the reaction is exothermic because an increase in the temperature of an exothermic reaction will shift the equilibrium position to the left.
Therefore, we can conclude that:
The reaction is exothermic because the system shifted to the left on heating.