A common unit to measure concentration is molarity (M). To calculate the molarity, you must know how many liters of solution you are working with.
Sometimes, you may not even be given the liters of solution. You may only have
a value in milliliters (ml).
Can you convert 968 milliliters to liters?
liters

the answer your looking for is c).

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