Question

1. Who gave law of conservation of mass ?
2. What term is used to represent the mass of 1 mole molecules of a substance?
3. What name is given to the number 6.023 x 1023 ?
4. What is molecular mass?
5. Give Latin names for sodium & mercury.
6. *How many atoms are there in exactly 12 g of carbon ?
7. Define mole.
8. Calculate formula unit mass of CaCl2. [ At. Mass : Ca = 40 u , Cl = 35.5 u ]
9. Name a diatomic gas.
10. How many atoms are present in H2SO4.
2 Marks Questions:
1. Give the chemical symbols for the following elements: Gold, Copper , Potassium & Iron.
2. What do the following symbols represent - i) 1 H & i) H2
3. Neon gas consists if single atoms , what mass of neon contain 6.022 x 1023 atoms.
4. What elements do the following compounds contain ? i) Water ii) Lead nitrate
5. State the differences between an atom or a molecule.
6. Molar Mass of water is 18 g mol-1 , what is the mass of 1 mole of water? .
7. The number of atoms in 1 mole of hydrogen is twice the number of atoms in one mole of helium. Why?
8. Write the chemical formulas for the following:
i) Silver oxide ii) Iron (III) sulphate
9. Calculate molar mass of H2O2 & HNO3.
10. What is the mass of 0.2 moles of oxygen molecules?
3 Marks Questions:
1. State the main postulates of John Dalton’s atomic theory.
2. What are polyatomic ions ? Give two examples.
3. State the following
i) Law of conservation of mass. ii) Law of constant proportion
4. What is the mass of :
i) 1 mol of N atoms. ii) 4 mol of Al atoms.
5. What is meant by the term atomicity ? State the atomicity of
i) Phosphorous ii) Sulphur
5 Marks Questions:
1. i) What is molecular formula ? State with example what information can be derived from a molecular formula .
ii) Write the names of the compounds represented by the following formulas:
a) Mg(NO3)2 b) K2SO4 c )Ca3N2
2. i) What is gram molecular mass?
ii) Write the formulas & names of the compounds formed between:
a) Ferrous and sulphide ions b) Aluminium and sulphate ions
c) Potassium and chlorate ions d) Barium and chloride ions
3. i) Calculate the number of moles for the following:
a) 52 g of He b) 17 g of H2O
ii) How many molecules are present in 34 g of ammonia ?
iii) Calculate the mass of 0.5 mole of sugar (C12H22O11).​

Answer 1

Answer:

1- The law of conservation of mass was given by Antoine Lavoisier's

5- sodium - Natrium

mercury- Hydrargyrum

10- two hydrogen atom, one sulfer atom, four oxygen atoms