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9th Class Examination 2015 Chemistry important Question / Notes Chapter 1 to 5

9th Class Examination 2015 Chemistry  important Question / Notes  Chapter 1 to 5

1. How does homogenous mixture differ from heterogenous mixture?
2. Differentiate between molecular mass and formula mass?
3. Define industrial chemistry and analytical chemistry?
4. What is empirical formula of acetic acid (CH3COOH)? Find out its molecular mass?
5. Find out the mass of 3 moles of oxygen atoms?
6. Define relative atomic mass.
7. Differentiate between physical and chemical properties.
8. How many times is 1 mole of oxygen atom heavier than 1 mole of hydrogen atom?
9. Differentiate between ions and free radicals.
10. Write down the relationship between mole and mass.

Long questions 5×1=5
1. (a) List five characteristics by which compound can be distinguished from mixture. 3
(b) How many total atoms are required to prepare 60g of HNO3? 2
1. What is atomic number of phosphorus? Write down its electronic configuration.
2. Write down the differences between Rutherford Atomic theory and Bohr’s Atomic theory.
3. What will be the nature of charge on an atom when it loses an electron or when it gains an electron?
4. Give three properties of positive rays.
5. What are the defects of Rutherford’s Atomic model?
6. What do you know about “Plum Pudding” theory?
7. Write down the electronic configuration of Cl- ion.
8. Give three characteristics of cathode rays.
9. Define electronic configuration.
10. What are shell and subshells?

Long Question 5×1=5
1. (a) Describe the postulates of Bohr’s Model of an atom. 3
(b) Describe the major applications of isotopes in our surroundings. 2
1. What do you mean by groups and periods in a periodic table?
2. Give the trend of ionization energy in a periodic table?
3. Why noble gases are not reactive?
4. State Mendeleev’s periodic law.
5. From which element lanthanide series starts?
6. Define ionization energy.
7. How can you define atomic radius?
8. Why the trend of electron affinity and electronegativity is same in a period?
9. What is shielding effect?
10. What is the reason of arranging elements in a group?

Long Questions 5×1=5
1. (a) Write down the salient features of long form of periodic table. 3
(b) Describe the trends of electronegativity in a period and in a group. 2
Why HCl has dipole-dipole forces of attraction?
1. Differentiate between lone pair and bond pair of electrons.
2. What do you mean by induced dipole?
3. Why the ionic compounds have high melting and boiling points?
4. Write down any two properties of metals?
5. What is octet rule?
6. Define coordinate and dative covalent bonding.
7. Define ionic bond. Write down any example of ionic bonding.
8. Ionic compounds are solid. Justify.
9. Why does ice float on water?

Long Questions 5×1=5
1. (a) Explain the types of covalent bonds with at least one example of each type. 3
(b) What is a chemical bond and why do atoms form a chemical bond? 2
1. Define diffusion. Explain with example.
2. What is absolute zero, give its value.
3. Define the term allotropy with examples.
4. Define standard atmospheric pressure. What is its unit?
5. Why the rate of diffusion of gases is rapid than that of liquids?
6. Define Boyle’s law.
7. Which form of sulphur exists at room temperature?
8. Define freezing point.
9. What are crystalline solid?
10. Define vapour pressure.

Long Questions 5×1=5
1. (a) Define boiling point. How it is affected by different factors? 3
(b) A gas occupies a volume of 800cm3 at 1atm, when it is allowed to expand to 1200cm3. What will be its pressure in mm of Hg?

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