Answer:
The answer to your question is below
Explanation:
When we have the number of an element followed by a number, that number is the atomic mass.
Atomic mass is the number of protons plus neutrons.
Protons Neutrons
Carbon-13 6 13 - 6 = 7
Chromium-51 24 51- 24 = 27
Strontium-88 38 88 - 38 = 50
Boron-10 5 10 - 5 = 5
In 1871, a Russian Chemist, Dimitri Mendeleev, gave a useful scheme for classification of elements. He presented the first regular periodic table in which elements of similar chemical properties were arranged in eight vertical columns called groups. The horizontal rows of table were called periods. He arranged elements in ascending order of their atomic masses and found that elements having similar chemical properties appeared at regular intervals. This observation was called Periodic Law.
Since an acidic salt solution is produced when a strong acid neutralizes a weak base, the pH of the salt solution formed when HCl is added to R2NH will be less than 7.
<h3>What is a neutralization reaction?</h3>
A neutralization reaction is the react ion between an acid and a base to form salt and water only.
Neutralization reactions can either produce a neutral solution, an acidic solution or an alkaline solution at equivalence point.
When a strong acid is added to a weak base, the pH of the salt solution formed will be less than 7.
Therefore, the pH of the salt solution formed when HCl is added to R2NH will be less than 7.
Learn more about pH at: brainly.com/question/940314
An an increase in
temperature lead to more effective collisions between reactant particles and an
increase in the rate of a chemical reaction because the number of
molecules with sufficient energy to react increases. The answer is number 3.
The answer is 3. The releasing of energy means exothermic reaction. So the ΔH should be negative. And the greatest quantity of energy released means that the greatest number. So according to the table I, the answer is 3.
