Answer:
The molarity of this solution is 14.82 mol/dm3 or 14.82 mol/L
Explanation:
- Molarity is the number of mole present in 1 Litre of solution. Molarity of a solution is a term referred to as concentration of a solution. The unit of Molarity is Mol/dm3 or Mol/L.
- let us make an assumption that the volume of the ammonia solution is 1L or 1dm3. Also, 1L = 1000 mL.
Step 1: calculate the mass of the solution
Density = 0.90g/ml (from the question)
Density = mass/ volume
Therefore Mass = density x volume
= 0.90g/ml x 1000ml
mass = 900 g
Step 2: calculate the mass of NH3 present in the solution
Since the concentrated aqueous of ammonia is 28%, It signifies that 1000ml of the solution contains 28% Ammonia
Recall from the above calculation that the mass of 1000 ml of solution is 900 g.
Therefore the mass of ammonia will be 28% of 900 g
mass of NH3 = 0.28 x 900 g
= 252 g
Step 3: calculate the number of mole of NH3
mole = mass/ molar mass
molar mass of NH3 = 17 g/mol
Therefore mole of NH3 = 252/17
= 14.82 mol
Step 4: Calculate Molarity
Molarity = number of moles/ volume of solution in Litre (L)
Molarity = 14.82 / 1
Molarity = 14.82 mol/L
Answer:
C.5
Explanation:
A number of electrons present in valence shell of penultimate Shell represents the group of elements.
For s block elements: no.of group=number of valence shell electron.
p block elements: no. of group= 2 + 10 + number of valence electrons.
d block elements: no. of group= number(n-1)d electrons + number of electrons in nth shell.
Here, the differential electron is in p orbital hence, it belongs to p block
No. of group= 2+ 10 + 3=15 i.e 15th group or VA group.
A. The number of valence electrons determines how it reacts with other elements.
<em>One to three valence electrons</em>: The element behaves like a metal and reacts with non-metals.
<em>Five to seven valence electrons</em>: The element behaves like a non-metal and reacts with metals.
<em>Four valence electrons</em>: Elements at the top of the Group are non-metals, while those at the bottom are metals.
<em>Eight valence electrons</em>: Elements have a complete octet, so they are generally unreactive.
