Density of any substance is mass of the substance per unit volume. Density, d=m/V, where m is mass of the substance and V is the volume occupied by the substance. The amount of water displaced by an object when it is submerged in water equals the volume of the object. So, due to submerge of piece of zinc alloy in water present in graduated cylinder, water level rises. The increase in the volume of water is the volume of the zinc piece.
Volume of water in graduated cylinder before addition of zinc piece (v₁)= 20 ml, Volume of water in graduated cylinder after addition of zinc piece (v₂)= 23.2 ml, Rise in the volume due to submerge of the piece = (v₂ - v₁)ml= 23.2-20.0= 3.20 ml. So, volume of the piece is 3.20 ml and mass of the zinc piece is 25.0 g.
Hence density zinc alloy is equal to g/ml= 7.81 g/ml= 7.8 g/ml (expressed in two significant figure).
1.66 M is the concentration of the chemist's working solution.
<h3>What is molarity?</h3>Molarity (M) is the amount of a substance in a certain volume of solution. Molarity is defined as the moles of a solute per litres of a solution. Molarity is also known as the molar concentration of a solution.
In this case, we have a solution of Zn(NO₃)₂.
The chemist wants to prepare a dilute solution of this reactant.
The stock solution of the nitrate has a concentration of 4.93 M, and he wants to prepare 620 mL of a more dilute concentration of the same solution. He adds 210 mL of the stock and completes it with water until it reaches 620 mL.
We want to know the concentration of this diluted solution.
As we are working with the same solution, we can assume that the moles of the stock solution will be conserved in the diluted solution so:
=
(1)
and we also know that:
n = M x
If we replace this expression in (1) we have:
x
=
x
Where 1, would be the stock solution and 2, the solution we want to prepare.
So, we already know the concentration and volume used of the stock solution and the desired volume of the diluted one, therefore, all we have to do is replace the given data in (2) and solve for the concentration which is :
4.93 x 210 = 620 x
= 1.66 M
This is the concentration of the solution prepared.
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Answer:
(a) Constitutional Isomers
(b) Constitutional Isomers
Explanation:
Constitutional isomers are also known with the name Structural Isomers. These are the compounds which have same chemical formula but differ in arrangement of atoms i.e. structure.
Both the compounds <em>cis-1,3-dibromocyclohexane</em> and <em>trans-1,4-dibromocyclohexane</em> have the same chemical formula but have different structure as shown in the image below.
In the second case the compounds <em>2,3-dimethylhexane</em> and <em>2,3,3-trimethylpentane</em>, both have same chemical formula but have different structures which is shown in the image below.
Thus it is clear that in both the groups (a) and (b) the given compounds are Constitutional Isomers.