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 10 23 ?
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.
Answers
Answer:
1. The Law of Conservation of Mass dates from Antoine Lavoisier's 1789 discovery that mass is neither created nor destroyed in chemical reactions. In other words, the mass of any one element at the beginning of a reaction will equal the mass of that element at the end of the reaction.
2. The molar mass of a substance is the mass in grams of one mole of that substance. This mass is given by the atomic weight of the chemical unit that makes up that substance in atomic mass units (amu).
3. This number (Avogadro's number) is 6.023 X 1023. It is the number of molecules of any gas present in a volume of 22.41 L and is the same for the lightest gas (hydrogen) as for a heavy gas such as carbon dioxide or bromine.
4. The molecular mass is the mass of a given molecule: it is measured in daltons. Different molecules of the same compound may have different molecular masses because they contain different isotopes of an element.
5. The Latin name for element mercury is Hydrargyrum, and for sodium is Natrium.
6. 12.00 g C-12 = 1 mol C-12 atoms = 6.022 × 1023 atoms • The number of particles in 1 mole is called Avogadro's Number (6.0221421 x 1023).
7. A mole is defined as 6.02214076 × 1023 of some chemical unit, be it atoms, molecules, ions, or others. The mole is a convenient unit to use because of the great number of atoms, molecules, or others in any substance.
Answer:
1. The Law of Conservation of Mass dates from Antoine Lavoisier's 1789 discovery that mass is neither created nor destroyed in chemical reactions. In other words, the mass of any one element at the beginning of a reaction will equal the mass of that element at the end of the reaction.
2. The molar mass of a substance is the mass in grams of one mole of that substance. This mass is given by the atomic weight of the chemical unit that makes up that substance in atomic mass units (amu).
3. This number (Avogadro's number) is 6.023 X 1023. It is the number of molecules of any gas present in a volume of 22.41 L and is the same for the lightest gas (hydrogen) as for a heavy gas such as carbon dioxide or bromine.
4. The molecular mass is the mass of a given molecule: it is measured in daltons. Different molecules of the same compound may have different molecular masses because they contain different isotopes of an element.
5. The Latin name for element mercury is Hydrargyrum, and for sodium is Natrium.
6. 12.00 g C-12 = 1 mol C-12 atoms = 6.022 × 1023 atoms • The number of particles in 1 mole is called Avogadro's Number (6.0221421 x 1023).
7. A mole is defined as 6.02214076 × 1023 of some chemical unit, be it atoms, molecules, ions, or others. The mole is a convenient unit to use because of the great number of atoms, molecules, or others in any substance.
Explanation: