Given below are the CBSE Important Questions(Long questions) for Atoms and Molecules
a) Concepts questions
b) Calculation problems
c) Multiple choice questions
d) Long answer questions
e) Fill in the blank's
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Mention the difference between 2N and N2
Nitrogen and Hydrogen combine in the ratio 14:3 by mass to form ammonia molecule. Find the formulae of ammonia molecule by calculating the molar ratio?
An element ‘Y’ forms an oxide whose chemical formulae is Y2
a)State the valency of Y.
b)Write the chemical formulae of its: (a) Sulphate and (b) Chloride?
Define mole? Calculate the number of moles in 22g of carbon dioxide?
State three rules for writing the chemical formulae.
Write the chemical formulae for the chloride of magnesium?
Write down the chemical formulae of:
Find the number of atoms present in:
If one mole of carbon atoms weighs 12g, what is the mass of 1atom of carbon?
Derive the formula of the compound formed between Na+
Write the chemical formulae for the compounds formed by the calcium ion with phosphate, sulphate and hydrogen carbonate ions?
Write the ratio by mass of Hydrogen and oxygen in one molecule of water?
State the number of hydrogen atoms in 1g of hydrogen?
The relative atomic mass of oxygen atom is 16. Explain its meaning?
Calculate the number of molecules of SO2
present in 44g of it?
If one molecule of oxygen atoms weighs 16g, find the mass of one atom of oxygen?
Sodium is represented as Na2311
a)What is its atomic mass?
b)Write its gram atomic mass?
c)How many atoms of Na will be there in 11.5 g of the sample?
Calculate the molar mass of the following compounds and identify the poly-atomic ions present in each of them:
Define formulae unit mass of compounds. Calculate the formulae unit mass of :
The atomic mass of calcium is 40u. What will be the number of calcium atoms in 0.4 of calcium?
Molar mass of nitrogen is 14u. What will be the mass of one atom of nitrogen?
How many atoms are present in:
Calculate the number of aluminium ions present in 0.051g of aluminium oxide?
Calculate the number of molecules of sulphur (S8) present in 8g of solid sulphur?
Calculate the number of molecules in 4g of methane?
Write down the names of compounds represented by the following chemical formulae:
Compare relative molar mass and relative formula unit mass?
What is the mass of:
a)1 mole of nitrogen atoms?
b)4 mole of aluminium atoms?
c)10 mole of sodium sulphite (Na2
d) 0.2 mole of water
Calculate the molar mass of HNO3
. Compare it with its formula unit mass?
30.A 0.48g sample of compounds of oxygen and boron was formed by analysis to contain 0.192 g of boron and 0.2888g of oxygen. Calculate the percentage composition of the compound by weight?
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Class 9 Maths
Class 9 Science