Answer:
Oxygen molecule is 2 oxygen atoms in a covalent bond, whereas an oxygen atom is an atom with 8 electrons (6 valence electrons).
Thus, clearly, any element in a bonded state is always more stable than when in an un-bonded state.
Explanation:
<h2>Answer:</h2>
This is a physical change.
<h3>
Explanation:</h3>
Hot asphalt is mixed with the sand crushed stones and spread onto the roads, when it gets dry it becomes hard giving a smooth straight surface of the road.
Asphalt is used to stick together stones and sand in the road.
It is a physical change because the phase of the asphalt changed from the liquid to solid.
At high temperature, asphalt is in liquid form and at room temperature, it is present in hard solid form.
Answer : The temperature of this gas will be, 206.9 K
Explanation :
The expression for the kinetic energy per molecule of monoatomic gas (argon) is:
...........(1)
The expression for the kinetic energy per molecule of diatomic gas (nitrogen gas) is:
.............(2)
The total kinetic energy of the molecule will be,

Now put all the expression in this, we get:


Now put all the given values in this expression, we get:


Therefore, the temperature of this gas will be, 206.9 K
I think the answer is water and hydrochloric acid
Answer : The mass of liquid sodium needed are, 
Explanation :
First we have to calculate the number of moles of liquid sodium.

where,
q = heat absorb = 1.20 MJ = 1.20 × 10⁶ J
n = number of moles of liquid sodium = ?
c = specific heat capacity = 
= change in temperature = 
Now put all the given values in the above formula, we get:


Now we have to calculate the mass of liquid sodium.
Molar mass of Na = 23 g/mol


Therefore, the mass of liquid sodium needed are, 