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Chemistry: What is Hydrogen? It's Uses, physical properties, chemical properties and methods of preparation

August 16, 2019


Hydrogen


Hydrogen is found in group one of the periodic table. Though, it is non-metal, it is usually placed in group one because it has one valence electron.

PERIODIC TABLE HYDROGEN



Physical Properties of Hydrogen
  •  It is a colourless, odourless and tasteless gas.
  • It is neutral to litmus paper.
  • It is insoluble in water.
  • It is the lightest substance known.
  • It has a very low boiling point of (-253-degree Celsius).
  • It is less dense than air.


Chemical Properties of Hydrogen


     1. It reacts with metals to found hydrides.

              
             2Na + H2 ---> 2NaH

     2. It burns in air to produce steam.
    
             H2O + O2 ---> 2H2O

    3. It reacts with halogens to produce halides

            H2 + Cl ---> 2Hcl
            H2 + 2Br ---> 2HBr

   4. Acts as a Reducing agent: It reduces oxides to their respective metals
  
           CuO + H2 ---> Cu + H2O


Uses of hydrogen
  • It is used in the hydrogenation of oil.
  • It is used to manufacture soap and margarine (saponification).
  • It is used in filling balloons.
  • Liquid hydrogen is used for rocket fuel.
  • It is used for welding metals.


Isotopes of hydrogen

Hydrogen has three naturally occurring Isotopes. There are;
  • Protium – ( 11H )
  • Deuterium – ( 12H )
  • Tritium - ( 13H )
“Deuterium oxide” is commonly known as heavy water because it is about 1.1 times heavier than water.  “Protium” has no neutrons, it is the ordinary isotope of hydrogen. “Tritium” is radioactive and rarely found in ordinary hydrogen.

TRITIUM


Read more about: Isotopes and isotopy (chemistry)


Laboratory Preparation of hydrogen

Hydrogen can be prepared in the laboratory by;

* Action of dilute acid on metal.
* Action of cold water on sodium.
* Action of steam on red hot iron


Laboratory preparation of hydrogen by the action of dilute acid on metal.

AIM – To prepare hydrogen.                                                                      

APPARATUS – Round bottom flasks, delivery tube, glass jar, thistle funnel, trough etc.

METHOD
  • Place some pieces of zinc metal in a round bottom flasks
  • Set up the apparatus.
HYDROGEN LABORATORY SET UP

  • Add dilute sulfuric acid (H2SO4) to zinc metal through the thistle funnel.
  • Collect the gas formed over water.

OBSERVATION – As soon as the metal effervescence occurs, gas liberated is collected over water.

CONCLUSION – Hydrogen can be prepared in the laboratory




Industrial preparation of hydrogen

Hydrogen can be prepared in large quantities in the industries by the following ways;
  • Water Gas
  • Hydrocarbon
  • Electrolysis


By Water Gas

When steam is passed over red hot coke at a temperature of about 1100 degree Celsius. The mixture of carbon (ii) oxide or hydrogen gas is produced and this is known as water gas.

H2O + C ---> CO + H2

The product obtained is mixed with excess steam and passed over iron(iii)oxide or Uranium (iii) oxide as a catalyst at a temperature of 450 degree Celsius.

During this process, carbon (ii) oxide in water gas is converted to carbon (iv) oxide and the liberation of excess hydrogen.

CO + H2 + H2O ---> CO + H2

Questions? Comment below.
        


Chemistry: What is Hydrogen? It's Uses, physical properties, chemical properties and methods of preparation Chemistry: What is Hydrogen? It's Uses, physical properties, chemical properties and methods of preparation Reviewed by uyi osamudiamen Lucky on August 16, 2019 Rating: 5

Isotopy and Isotopes; definition,questions and solution. - chemistry

August 16, 2019


isotopes


Isotopy and isotopes

Isotopy can be defined as a process/occurrence/phenomenon whereby an element has the same atomic number (i.e the number of protons) but different mass number (i.e number of neutrons).




  • Proton 
  • Neutron
  • Electron


Isotopes are the elements that have the same atomic number (number of protons) and different mass number (number of neutrons). Examples of isotopes are;

Chlorine    3517Cl , 3717Cl


Oxygen        168O , 178O , 188O

Hydrogen     11H ,21 H , 31H

Carbon          126C , 136C

Sodium      2311Na , 2411Na

Lithium           63Li  , 73Li



Worked Examples:
Question 1
there are two isotopes of chlorine with mass numbers 35 and 37 respectively. if the isotopes exist in the ratio 3:1 , the lighter isotope being more abundant. what is the relative atomic mass of chlorine?

solution
1st isotope   35Cl
2nd isotope   37Cl
the isotopic ratio = 3:1
Total ratio = 3 + 1 = 4
% abundance of  35Cl = (3/4 x 100) = 75%
% abundance of  37Cl = (1/4 x 100) = 25%
Relative atomic mass of chlorine (R.A.M) = (75/100 X 35) + (25/100 X 37) = 3550/100
Relative atomic mass of chlorine (R.A.M) = 35.5

Question 2
Boron exist as an isotopic mixture containing 80% of B , 15% of B and 5% of B. Calculate the  relative atomic mass of Boron?

solution
1st isotope   9B
2nd isotope 10B
 3rd isotope 11B
the % abundance ratio = 80:15:5

Relative atomic mass of chlorine (R.A.M) = (80/100 X 9) + (15/100 X 10) +  (5/100 X 11)  = 925/100
Relative atomic mass of boron (R.A.M) = 92.5

Question 3
If the relative atomic mass of natural copper is 63.54. Calculate the proportions of isotopes 63CU and 65CU in the metal?

solution
1st isotope   63Cu
2nd isotope   65 Cu
Let the proportion of cu be x
Let the proportion of cu be y
therefore, x + y = 100  ...................(1)
Relative atomic mass of copper (R.A.M) = (x/100 X 63) + (y/100 X 65) = 63.54
                                                                63.54 = 0.63x + 0.65y   .............(2)  
 from equation (1);  y = 100 - x
 substitute for y in the equation (2) above  63.54 = 0.63x + 0.65(100 - x)
 63.54 = 0.63x + 65 - 0.65x
 1.46 = 0.02x
  x = 0.73 (=73%)
  recall; y = 100 - x
   y = 100 - 73
    y = 27%

Question 4
Two isotopes of z with mass number 18 and 20 are in the ratio 1:2. Determine the relative atomic mass.

solution
1st isotope   20Z
2nd isotope  18 Z
the isotopic ratio = 1:2
Total ratio = 2 + 1 = 3
% abundance of  20 Z = (2/3 x 100) = 66.6%
% abundance of  18 Z = (1/3 x 100) = 33.3%
Relative atomic mass of Z (R.A.M) = (66.6/100 X 20) + (33.3/100 X 18) = 1931.4/100
Relative atomic mass of Z (R.A.M) = 19.314.





Isotopy and Isotopes; definition,questions and solution. - chemistry Isotopy and Isotopes; definition,questions and solution. - chemistry Reviewed by uyi osamudiamen Lucky on August 16, 2019 Rating: 5
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