Answer:
4.46 x 10^-22 nitrate ions
Step-by-step explanation:
To find the number of nitrate ions present in 4.18 x 10^-20 grams of copper (II) nitrate, we need to use the molar mass of copper (II) nitrate and Avogadro's number.
The molar mass of copper (II) nitrate is:
Cu(NO3)2 = 63.55 g/mol (Cu) + 2(14.01 g/mol (N) + 3(16.00 g/mol (O))) = 187.57 g/mol
So 1 mole of copper (II) nitrate has a mass of 187.57 grams.
We can find the number of moles of copper (II) nitrate in 4.18 x 10^-20 grams by dividing the mass by the molar mass:
4.18 x 10^-20 g / 187.57 g/mol = 2.23 x 10^-22 moles
Each mole of copper (II) nitrate contains 2 moles of nitrate ions. Therefore, the total number of nitrate ions in 4.18 x 10^-20 grams of copper (II) nitrate is:
2.23 x 10^-22 moles x 2 nitrate ions/mole = 4.46 x 10^-22 nitrate ions
So there are approximately 4.46 x 10^-22 nitrate ions in 4.18 x 10^-20 grams of copper (II) nitrate.