Answer:
if the heat of reaction is positive, the reaction is said to be endothermic; if negative, exothermic.
Explanation:
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Answer:
Oxygen
Explanation:
If two balloons are filled with hydrogen gas and helium gas respectively, then we want to identify what gas is in each balloon, we have to do so by exposing the both balloons to flame in an oxygen atmosphere.
Hydrogen combines with oxygen in the presence of a flame with quite a loud sound and the flame is sustained but when a flame is brought near helium gas in a balloon, the gas will only make a little sound when exposed to the flame and extinguish the flame.
The reason for the explosion of the gas in the hydrogen balloon is that combustion of hydrogen gas is exothermic. The heating up of surrounding air molecules leads to a sudden explosion.
However, the helium balloon makes a little sound when the balloon is ruptured releasing helium gas which extinguishes the flame.
Answer:
Antigens are molecules capable of stimulating an immune response. Each antigen has distinct surface features, or epitopes, resulting in specific responses. Antibodies (immunoglobins) are Y-shaped proteins produced by B cells of the immune system in response to exposure to antigens.
Answer:
Solid Rocky Dense
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Answer:
Peptide bonds form from nucleophilic attack by an α‑carboxyl carbon atom on an electron pair of an α‑amino nitrogen atom of another amino acid.
Explanation:
Peptide bond is a form of covalent bond and it is Amide type that is formed between two molecules when carboxyl group react with one molecule of amino group to release molecule of water.The peptide bond are in form pseudo-double bond characteristic; rigid, planar, and stronger than a typical Carboxyl nitrogen single bond.
Peptide bonds form from nucleophilic attack by an α‑carboxyl carbon atom on an electron pair of an α‑amino nitrogen atom of another amino acid.
