16. _ Na + __Br2 →_NaBr

→

Explanation:

→

On the left you have:

Na: 1

Br: 2

On the right you have:

Na: 1

Br: 1

To get the Br to be the same on both sides, you would multiple the NaBr by 2. Then, you will have 2 Na so you put a coefficient of 2 in front of the Na aswell.

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