Answer:
Elements are pure substances which are composed of only one type of atom. Compound are substances which are formed by two or more different types of elements that are united chemically in fixed proportions. ... Some of the examples of elements are Iron, Copper, Gold, etc. A few examples of compounds are NaOH, NaCl, etc.
I believe the answer is option B. The bonded pair of valence electrons are shown using circles
Answer:
Ka = ( [H₃O⁺] . [F⁻] ) / [HF]
Explanation:
HF is a weak acid which in water, keeps this equilibrium
HF (aq) + H₂O (l) ⇄ H₃O⁺ (aq) + F⁻ (aq) Ka
2H₂O (l) ⇄ H₃O⁺ (l) + OH⁻ (aq) Kw
HF is the weak acid
F⁻ is the conjugate stron base
Let's make the expression for K
K = ( [H₃O⁺] . [F⁻] ) / [HF] . [H₂O]
K . [H₂O] = ( [H₃O⁺] . [F⁻] ) / [HF]
K . [H₂O] = Ka
Ka, the acid dissociation constant, includes Kwater.
so this is right answer
For reasons that are unclear, no eukaryotic enzymes can break the triple bond of N2. The reduction of N2 to NH3 (nitrogen fixation) is limited to prokaryotes and is catalysed by nitrogenase. Since most of the nitrogen entering the biosphere (around 100 million metric tonnes of N2 per annum) does so through nitrogenase activity (lightning contributes about 10%), those plants that associate with nitrogen-fixing bacteria have a significant selective advantage under conditions of limiting nitrogen.
Answer:
6750 J
Explanation:
The specific heat capacity of iron is 450 J/kg/K
Quantity of heat = mcθ; where m is the mass and c is the specific heat capacity and θ is the temperature change.
Therefore;
m = 3 kg, c = 450 J/kg/K and θ = 5°C
Quantity of heat = 3 × 450 × 5
<u>= 6150 Joules</u>