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How many grams of neon will have the same number of atoms as 4 grams of calcium ? (Atomic masses : `Ne = 20 u, Ca = 40 u`) |
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Answer» To solve such problems we should remember that "equal number of moles of all the elements contain equal number of atoms". (i) Let us first convert 4 grams of calcium into moles. We have been given that the atomic mass of calcium is 40 u, so 1 mole of calcium is `40` grams. Now, `40 g` of calcium `= 1` mole So, `4 g` of calcium `= 1/40 xx 4` mole `= 1/10` mole Now, `1/10` mole of calcium will have the same number of atoms as `1/10` mole of neon. So, we should now convert `1/10` mole of neon into mass in grams. (ii) The atomic mass of n eon is `20u`, so 1 mole of neon will be equal to 20 grams. Now, `1` mole of neon `= 20 g`, So, `1/10` mole of neon `= 20 xx 1/10` g `= 2 g` Thus, 2 grams of neon will contain the same number of atoms as 4 grams of calcium. |
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