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प्रश्न
Calculate the number of moles of magnesium present in a magnesium ribbon weighing 12 g. Molar atomic mass of magnesium is 24g mol–1.
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उत्तर
Atomic mass of Mg = 24 g mol-1
24 g of Mg = 1 mol
12 g of Mg = `12/24`
= 0.5 mol
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संबंधित प्रश्न
A gas cylinder can hold 1 kg of hydrogen at room temperature and pressure
1) Find the number of moles of hydrogen present.
2) What weight of CO2 can the cylinder hold under similar conditions of temperature and pressure? (H = 1, C = 12, O = 16)
3) If the number of molecules of hydrogen in the cylinder is X, calculate the number of CO2 molecules in the cylinder under the same conditions of temperature and pressure.
4) State the law that helped you to arrive at the above result.
What is meant by ‘a mole of carbon atoms’ ?
Explain with examples what is meant by a 'mole' of a substance.
Correct the following statement :
Equal masses of all gases under identical conditions contain the same number of molecules.
Complete the following calculations. Show working for complete credit :
Calculate the mass of calcium that will contain the same number of atoms as are present in 3.2 gm of Sulphur. [Atomic masses : S = 32, Ca = 40]
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]
A gas cylinder can hold 1 kg of hydrogen at room temperature and pressure.
(a) Find the number of moles of hydrogen present
(b) What weight of CO2can the cylinder hold under similar conditions of temperature and pressure? (H = 1 C = 12, O = 16)
(c) If the number of molecules of hydrogen in the cylinder is X, calculate the number of CO2 molecules in the cylinder with the same conditions of temperature and pressure.
(d) State the law that helped you to arrive at the above result.
Define or explain the term:
Relative atomic mass
Calculate the mass of 0.1 mole of the following:
Na2SO4.10H2O
(Ca = 40, Na = 23, Mg = 24, S = 32, C = 12, Cl = 35.5, O = 16, H = 1)
Deduce the number of molecules of the following compound in the given quantity.
7.1 g chlorine
