The volume of a sample of hydrogen gas was decreased from 12.85 l to 6.14 l at constant temperature. if the final pressure exerted by the hydrogen gas sample was 7.40 atm, what pressure did the hydrogen gas exert before its volume was decreased?

3.79 atm Explanation: Assuming ideal behavior, the gas sample should satisfy the Boyle's law, which states that P ⋅ V = a constant when temperature is held constant. [1] In other words, the pressure the gas exerts is inversely related to the volume of the airtight container. Therefore P 1 ⋅ V 1 = P 2 ⋅ V 2 P 1 = P 2 ⋅ V 2 V 1 = P 2 ⋅ V 2 V 1 Evaluate with V 1 = 13.16 L , V 2 = 6.45 L , P 2 = 7.73 atm as given in the question: P 1 = 7.73 atm ⋅ 6.45 L 13.16 L = 3.79 atm (rounded to three significant figures)

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