Answer:
Explanation:
Melting and boiling point variations are not clear (do not have uniform pattern) in periodic table. But we can see, some elements have higher melting and boiling points and some have less. Here we study melting and boiling points of s, p, d blocks elements. IVAth group elements (C,Si) show high melting and boiling points because they have covalent gigantic lattice structures.
Answer: There are 0.00269 moles of acetic acid in buffer.
Explanation:
To calculate the number of moles for given molarity, we use the equation:
.....(1)
Molarity of acetic acid solution = 0.0880 M
Volume of solution = 30.6 mL
Putting values in equation 1, we get:

Thus there are 0.00269 moles of acetic acid in buffer.
A, The moon pulls on the earth making the tides rise and fall
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.
<span>There are three different subatomic particles present in the atoms of each element: neutron, proton and </span>electron<span>. It is the </span>electrons<span>, and more specifically the valence </span>electrons<span>, that determine the reactivity of an element.</span>