Download App

Atoms and Molecules — Science STD 9 — Question

CBSE BoardEnglish MediumSTD 9ScienceAtoms and Molecules2 Marks
Question
Define the atomic mass unit.
✓

Answer

One atomic mass unit is equal to exactly one-twelfth (1/12th) the mass of one atom of carbon-12. The relative atomic masses of all elements have been found with respect to an atom of carbon-12.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "Answer the questions.[Che-2M]" from Atoms and Molecules→Atoms and Molecules — all question types→Science STD 9 question papers→CBSE Board STD 9 question papers→CBSE Board question paper generator→

Similar questions

What is a chemical change?
Give two examples of chemical changes.
→
If sulphur exists as S8 molecules, calculate the number of moles in 100g of sulphur.
(S = 32u)
→
State two reasons for supposing that brass is a mixture and not a compound.
→
How do solids, liquids and gases differ in shape and volume?
→
Classify the following into elements and compounds:
  1. H2O
  2. He
  3. Cl2
  4. CO
  5. Co
→

The atomic number of calcium and argon are 20 and 18 respectively, but the mass number of both these elements is 40. What is the name given to such a pair of elements?

→
Give reason:
  1. Plasma is found in the stars. 
  2. The molecules of a solid have the strongest intermolecular forces.
→
Give reasons for the following observation:
The smell of hot sizzling food reaches you several metres away, but to get the smell from cold food you have to go close.
→
Cinnabar (HgS) is a prominent ore of mercury. How many grams of mercury are present in 225g of pure HgS? Molar mass of Hg and S are 200.6g mol–1 and 32g mol–1 respectively.
→
Define the term ‘latent heat of vaporization’ of liquid. What is the value of the of the latent heat of vaporization of water?
→