A
nswer: -
C. Energy is released by the reaction
Explanation:-
An exothermic reaction is one in which during the progress of the reaction heat is evolved.
So energy is released by the reaction.
It cannot be created as energy is neither created nor destroyed as per the Law of conservation of energy. Energy is not transferred either.
The energy released during the progress of the reaction originates from the chemical bonds of the reactants as they break during their conversion into products.
Answer:
T2 = 94.6 C
Explanation:
Use Clausius-Clayperyon equation.
ln P1/P2 = ∆Hvap/R (1/T2 - 1/T1) where R = 8.314 J/mol-K and T is in degrees K
P1 = 760 mmHg
P2 = 630 mmHg
T1 = 373 K
T2 = ?
∆Hvap = 40.7 kJ/mole
R = 0.008314 kJ/mole-K (NOTE: change R to units of kJ)
Plug in and solve for T2
ln 760 mmHg/630 mmHg = 40.7 kJ/mole (1/T2 - 1/373K)
T2 = 367.74 K = 94.6 C
<span>Energy is transferred through the separate trophic levels of a food chain or web by feeding.The first trophic level (producers) is that of plants which are examples of autotrophs – they make their own food. Photosynthesis occurs when the plants use solar energy and convert it into chemical energy so it can be stored in a carbon compound. Once this has happened the energy can be taken up by the primary consumers – these are in the second trophic level (herbivores and omnivores). Secondary consumers also need to gain energy in some way, and this is by eating the primary consumers that have gained energy from the producers, this means that the second trophic level has successfully transferred energy into the third level containing omnivores and carnivores. A succession in energy transferral means that a food web or food chain has a tertiary and/or quaternary trophic level which can contain carnivores and omnivores which are plant and animal eaters (this includes humans).This transfer in energy is fairly efficient for the organisms involved as around 10% of light energy that is converted into chemical energy through photosynthesis is transferred through the trophic levels, the rest is lost in respiration, as heat, faeces and urine. Not all of the energy can be passed along a food web or chain as it must be used in other things too, so it cannot be 100% efficient.</span>