Answer: Option (E) is the correct answer.
Explanation:
A spontaneous reaction is defined as the process which tends to occur on its own. And, a non-spontaneous reaction is defined as a process for the completion of which we have to provide certain conditions.
For example, ice melting at 
is spontaneous primarily due to the increase in molecular disorder (dispersal of matter). Also, melting of ice is taking place on its own without any external force.
It is not necessary that all exothermic reactions will be exothermic in nature.
Thus, we can conclude that the statement all exothermic reactions are spontaneous, is false.
Answer:
Option A (0.043 g) is the correct answer.
Explanation:
Given:
= 43 mg
As we know,
then,
⇒ 
Thus, the above is the correct alternative.
Answer:
Explanation:
The question is not complete, the cmplete question is:
Identify one type of noncovalent bond present in each solid.
1) Table salt (NaCl) 2) Graphite (repeating)
a. hydrogen bonds
b. ionic interactions
c. van der Waals interactions
d. hydrophobic interactions
Answer:
1) Table salt
b. ionic interactions
Ionic bond are formed between atoms with incomplete outermost shell. Some atoms add electrons to their outermost shell to make the shell complete hence making it a negative ion while some atoms loses their electron to make the outermost shell complete becoming a positive ion. In NaCl, sodium (Na) has 1 electron in its outermost shell which it transfers to Cl which has 7 electrons in the outermost shell. Hence after the bonding the outermost shell of the atoms become complete.
2) Graphite
c. Van Der Waals interaction
Van der waal forces are weak interaction between molecules that exist between close atoms. Carbon atoms in graphite planes have covalent bond, these graphite planes are known as graphenes. Bonds between graphenes are very weak and are van der waals forces.
