Answer:
120g Using Density Equation.
Explanation:
Density =mass/volume
We need to the solve for the mass.
Mass=Density * Volume
Mass= 2.40 g/ml * 50.0 ml = 120g
Answer:
(a) Alkali metals: Francium (Fr)
(b) Chalcogens: Polonium (Po)
(c) Noble gases: Radon (Rn)
(d) Alkaline earth metals: Radium (Ra)
Explanation:
In the periodic table, the atomic mass increases down the group. Therefore, the last element of a group is the heaviest element of the group.
(a) alkali metals: The chemical elements that are present in group 1 of the periodic table, except hydrogen.
<u>The heaviest member of this group is francium (Fr)</u>
(b) chalcogens: The chemical elements that are present in group 16 of the periodic table
<u>The heaviest member of this group is polonium (Po)</u>
(c) noble gases: The chemical elements that are present in group 18 of the periodic table
<u>The heaviest member of this group is radon (Rn)</u>
(d) alkaline earth metals: The chemical elements that are present in group 2 of the periodic table.
<u>The heaviest member of this group is radium (Ra)</u>
Answer:
∆H or Enthalpy of the reaction
Explanation:
If ∆H is +ve
- Reaction is exothermic
- Example:-Combustion, mixing sodium/potassium in water
If ∆H is -ve
- Reaction is endothermic
- Ex:-Melting of ice
Answer:
The hydrogen ion concentration of the substance is 3.16*10⁻⁵ M
Explanation:
pH is a parameter used to measure the degree of acidity or alkalinity of a substance. The pH is calculated as the negative logarithm (base 10) of the concentration of hydronium ions [H₃O⁺] or hydrogen ions [H⁺].
pH= - log [H₃O⁺]= - log [H⁺]
Values on the pH scale range from 0 to 14, where pH equal to 7 is neutral, below 7 is acidic and above 7 is basic.
In this case, pH= 4.5
So:
4.5= - log [H⁺]
Solving:
[ H⁺]= 10⁻⁴ ⁵
[H⁺]= 3.16*10⁻⁵ M
The hydrogen ion concentration of the substance is 3.16*10⁻⁵ M
