Explanation:
d. endothermic change as
heat is added to solid ice to change it to liquid water
Carbon has four valence electrons. These electrons are associated for a specific atom and is responsible for forming a bond to different atoms. For carbon, in order to agree with the octet rule, it should have 4 more electrons. For an oxygen atom, there are 6 valence electrons present so it would need two more electrons. Thus, carbon atoms would share electrons with another two oxygen atoms wherein each oxygen atom would form double bonds with the carbon atom. So, the characteristics of these bonds would be that all of the four valence electrons of the carbon are being shared.
<span>Isotopes of the same element differ in their "Atomic masses"
Hope this helps!</span>
Answer:
The pH of 500 cm³, 0.2 mol/dm³, Ca(OH₂) is ≈ 13.6
Explanation:
The given parameters are;
Concentration of the calcium hydroxide, Ca(OH₂) = 0.2 mol/dm³
Volume of the calcium hydroxide, Ca(OH₂) = 500 cm³
Given that the calcium hydroxide, Ca(OH₂), undergoes complete ionization in water, complete dissociation, we have;
Ca(OH₂) ⇄ Ca²⁺ + 2 OH⁻
Therefore, we have;
2 moles of [OH⁻] for each mole of Ca(OH₂) which gives the concentration of [OH⁻] as
[OH⁻] = 2 × 0.2 ≈ 0.4 mol/dm³
The pH is given by the formula
pH = 14 + ㏒₁₀ [OH⁻]
pH = 14 + ㏒₁₀ (0.4) = 14 - 0.3979 = 13.6021 ≈ 13.6
The pH of the 500 cm³ 0.2 mol/dm³ Ca(OH₂) ≈ 13.6.
