Answer:
The internal energy(ΔE) of a substance is calculated below:
From the first law of thermodynamics;
ΔE=q+w
Explanation:
<u>ΔE=q+w</u>
here;
+q=endothermic reaction
-q=exothermic reaction
+w=work done on the system
-w=work done by the system
Given:
q=+1.62kJ=1620J
w=-874J
To solve:
the internal energy(ΔE)
We know:
ΔE=q+w
<em>according to the problem;</em>
ΔE=q-w
since;
w=-874J (i.e.)work is done by the system.
ΔE=1620-874
ΔE=+746J
Therefore the internal energy is +746J
i.e. the option is "c"(+746J)
Im pretty sure A slippery
Answer:
One nucleophilic center
Explanation;
Nucleophile:
Nucleophile is a substance which is nucleus loving in nature (<em>Nucleo</em>; Nucleus , <em>phile</em>; Loving). It is known as a specie which donates a lone pair of electrons to electrophile (electron loving) in a chemical reaction.
Thus, Nucleophile is the region of higher electron density in a molecule and attacks on the lower electron density region of another molecule. Also, the nucleophile can also contain a negative charge.
Number of Nucleophilic centers in Methanol:
The chemical structure of Methanol is attached below and it can be observed that the oxygen atom is containing two lone pair of electrons. Hence, the oxygen atom can act as a nucleophilic center. Therefore, there is only one nucleophilic center in methanol.
H₃C-OH + H₃C-Br → H₃C-O-CH₃ + HBr
In above reaction methanol is acting as a nucleophile and is attacking on electrophilic center (Carbon) of methyl bromide yielding dimethyl ether.
Answer:
The correct answer is option C.
Explanation:
Heat of formation is defined as change in enthalpy during the formation of 1 mole of compound from its constituent elements in its standard states.it is denoted by symbol . Its units are Kilo joules per mole.
- If <0, the change in enthalpy is negative then it means that energy is released during the formation of 1 mole of substance.
- If >0 , the change in enthalpy is positive then it means that energy is absorbed during the formation of 1 mole of substance.
For example:
286 kilo Joules of energy given out when 1 mole of liquid water is formed.