A gas cylinder of 53.7 L volume contains N2(g) at a pressure of 28.2 atm and 26C. How many grams of Ne(g) must we add to this same cylinder to raise the total pressure to 75.0 atm?

i believe you are right for all except the 3rd ( look at sqdancefan his answer is much better)

answerleaving cheese out to get moldy;

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