1. What volume in mL of 28.0M H2SO4 is needed to contain 53.0g of H2SO4?
2. How many grams of calcium hydroxide Ca(OH)2 are needed to make 532.0 mL of a 1.90M solution?
3. If 12 mL of water are added to 124mL of a 0.505M K2SO4 solution, what will the molarity of the diluted solution be?

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