<span>The key difference between Mendeleev and modern periodic table is that Mendeleev’s periodic table was based on the increasing atomic masses while the modern periodic table is based on the increasing atomic numbers. Let us see here what is Mendeleev periodic table and what is modern periodic table, and then compare both to understand the difference between both periodic tables. Mendeleev is the pioneer of the modern periodic table, though a numerous number of changes had been made to the old version of the periodic table. Both of these attempts are equally important to the scientific community; because without an invention of the periodic relationship in elements, the modern developments in Science would not reach a development era as today. Before the invention of Mendeleev’s classification, there were several attempts made by several chemists, but their periodic laws were inadequate to apply for all the elements. The modern periodic table is so advantageous for the development in the Science.</span>
Radical, in chemistry, molecule that contains at least one unpaired electron. Most molecules contain even numbers of electrons, and the covalent chemical bonds holding the atoms together within a molecule normally consist of pairs of electrons jointly shared by the atoms linked by the bond.
Answer:

Explanation:
The original calculation to find the number of moles which is
can be rearranged to give the equation
. Therefore the amount of molecules can be found by
(multiplying by Avogadro's Number)
Answer:
High temperatures
Explanation:
NaHCO₃ (8) + HCH,O₂ (aq) → H₂O (l) + CO₂ (g) + NaC,H₃O₂ (aq)
As the flask gets cooler to the touch as the reaction proceeds, the reaction is endothermic. This means that ΔH is positive (ΔH>0).
As a gas is formed (bubbles are formed), ΔS is positive (ΔS>0).
<em>In terms of ΔG:</em>
<em>In order for the reaction to be thermodynamically favorable, ΔH has to be negative</em>, thus:
- The reaction is favorable if TΔS > ΔH.
The greater the temperature, the easier it would be for TΔS to be greater than ΔH.
The heat absorbed to raise temperature : Q = 31350 J
<h3>Further explanation
</h3>
Given
m = mass = 150 g
Δt = Temperature difference : 50 °C
Required
Heat absorbed
Solution
Heat can be formulated
<em>
Q = m.c.Δt
</em>
The specific heat of water = c = 4.18 J/g °C
Input the value :
Q = 150 x 4.18 x 50
Q = 31350 J