A. 1
B. 4
C. 5
D. 3
E. 2
The correct answer is E. 2
Explanation:
- Evaporation is defined as a process in which liquid state of water is changing into vapor state.
So, we need to break the bonds of liquid substance in order to convert it into vapor state. And, energy is absorbed for breaking of bonds which means that evaporation is an endothermic process.
Hence, the statement evaporation of water is an exothermic process is false.
- When a hydrocarbon reacts with oxygen and leads to the formation of carbon dioxide and water then this type of reaction is known as combustion reaction.
A combustion reaction will always release heat energy. Hence, combustion reaction is exothermic in nature.
- When energy is transferred as heat from the surroundings to the system then it means energy is being absorbed by the system. And, absorption of heat is an endothermic process for which
is positive.
- Whereas when energy is transferred from system to the surrounding then it means energy is released by the system which is an exothermic process.
Hence, for an exothermic process value of is negative.
Thus, we can conclude that statements which are true are as follows.
- A combustion reaction is exothermic.
- When energy is transferred as heat from the system to the surroundings, is negative.
- For an endothermic reaction Deta H is positive.
Answer:
amino group
Explanation:
There are twenty (20) amino acids in nature. Generally, each amino acid is structurally made up of a central carbon atom called alpha carbon attached to a hydrogen, carboxylic acid group (-COOH) and an amine group (-NH2). However, one particular amino acid called PROLINE posseses an exception to this.
Proline, which is the only cyclic amino acid, is also the only amino acid that forms a secondary amine group i.e. loss of hydrogen atoms in its amine group when in a protein structure. This means that when in a protein, PROLINE does not have an AMINE GROUP.
Answer:
53% aluminium is present.
Explanation:
Given data:
Mass of aluminium in bauxite = 108 g
Total mass of sample = 204 g
Percentage of aluminium = ?
Solution:
Formula:
Percentage = Mass of aluminium / total mass of sample× 100
Now we will put the values in formula:
Percentage = 108 g/204 × 100
Percentage = 0.53 × 100
Percentage = 53%
So in given 204 g of bauxite there is 53% aluminium is present.
Answer:
Explanation:
They play a very important part. The geometry is not a straight line. It is an angle over 90 which means that the molecule has the same general shape as a boomerang. The two hydrogens and the 2 lone electron pairs try to get away as far as possible from each other. The actual shape results in a tetrahedron shape. But the two hydrogens and 1 oxygen actually look like the aforementioned boomerang.
