Advertisements
Advertisements
प्रश्न
If 0.2 mol of the following substance is required how many grams of that substance should be taken?
magnesium oxide
Advertisements
उत्तर
Molar mass of MgO = 24 + 16 = 40 g/mol
Number of moles of a substance = `"Mass of the substance in grams"/"Molecular mass of the substance"`
Let Mass of the substance in grams be x,
`0.2 = "x"/40 = 8`g
we need, 8g of MgO to obtain 0.2 moles of MgO.
APPEARS IN
संबंधित प्रश्न
Calculate the molar mass of the following substance:
Phosphorus molecule, P4 (atomic mass of phosphorus = 31)
Calculate the number of moles in 12g of oxygen gas.
Fill in the following blanks :
64 g of oxygen gas contains ................ moles of oxygen atoms.
If 16 g of oxygen contains 1 mole of oxygen atoms, calculate the mass of one atom of oxygen.
What is the mass of 5 moles of sodium carbonate (Na2CO3) ?
(Atomic masses : Na = 23 u ; C = 12 u ; O = 16 u)
Calculate the mass in grams of 0.17 mole of hydrogen sulphide, H2S. (Atomic masses : H = 1 u, S = 32 u)
Define mole. What are the two things that a mole represents.
What weight of each element is present in 1.5 moles of sodium sulphite, Na2SO3 ?
(Atomic masses : Na = 23 u ; S = 32 u ; O = 16 u)
Which of the following pair of elements represents a mole ratio of 1 : 1 ?
Prove the Following :
One mole of any gas contains th e same number of molecules.
The relative atomic mass of Cl atom is 35.5 a.m.u. Explain this statement.
Given that the relative molecular mass of copper oxide is 80, what volume of ammonia (measured at STP) is required to completely reduce 120g of copper oxide? The equation for the reaction is :
3CuO + 2NH3 → 3Cu + 3H2O + N2
Consider the following reaction and based on the reaction answer the questions that follow :
\[\ce{(NH4)2Cr2O7 ->[heat] N2(g) + 4H2O(g) + Cr2O3}\]
Calculate :
(i) The quantity in moles of (NH4)2Cr2O7 if 63 gm of (NH4)2Cr2O7 is heated.
(ii) The quantity in moles of nitrogen formed.
(iii) The volume in litres or dm3 of N2evolved at STP.
(iv) The mass in grams of Cr2O3 formed at the same time
[Atomic masses : H = 1, Cr=52, N=14]
Define the term:
Relative molecular mass
Find the number of molecules in 1.8 g of H2O.
How many grams of Al are present in 0.2 mole of it?
Determine the number of molecules in a drop of water which weighs 0.09 g.
Solid ammonium dichromate decomposes as:
\[\ce{(NH4)2Cr2O7 -> N2 + Cr2O3 + 4H2O}\]
If 63 g of ammonium dichromate decomposes. Calculate the quantity in moles of nitrogen formed.
How many grams are there in the following?
5 moles of sulphur molecule, S8
