Calculate the number of molecules in 895 g of H2O.

The number of molecules in 895 g of H₂O is 4.49*10²⁵.

Explanation:

Avogadro's Number or Avogadro's Constant is called the number of particles that make up a substance (usually atoms or molecules) and that can be found in the amount of one mole of said substance. Its value is 6.023*10²³ particles per mole. Avogadro's number represents a quantity without an associated physical dimension, so it is considered a pure number that allows describing a physical characteristic without an explicit dimension or unit of expression. Avogadro's number applies to any substance.

In this case, the molar mass of compound H₂O is 18 g / mol. So if 18 grams of H₂O are present in 1 mole, 895 grams will be present in how many moles of H₂O?

moles of H₂O= 74.58

Then the following rule of three can be applied: if 1 mole of the compound contains 6.023 * 10²³ molecules by definition of Avogadro's number, 74.58 moles of the compound how many molecules will it contain?

amount of molecules=4.49*10²⁵

The number of molecules in 895 g of H₂O is 4.49*10²⁵.

percent abundance for cu-63 can be shown as:

63 x + 65 (1-x) = 62.9296

65 - 62.9296 = 2 x

x = 1.035

thus, percent abundance for cu-63 is 1.035

percent abundance for cu-65 can be shown as:

63 x + 65 (1-x) = 64.9278

65 - 64.9278 = 2 x

x = 0.0361

thus, percent abundance for cu-63 is 0.0361

the mass spectrum of cu-63 showing the intense peak as, this isotope is found in nature more abundantly around 92.38 % in comparison to cu-65 which is found 62.58 % naturally