Answer:
71 Ga has a naturally abundance of 36%
Explanation:
Step 1: Given data
Gallium has 2 naturally occurring isotopes: this means the abundance of the 2 isotopes together is 100 %. The atomic weight of Ga is 69.72 amu. This is the average of all the isotopes.
Since the average mass of 69.72 is closer to the mass of 69 Ga, this means 69 Ga will be more present than 71 Ga
Percentage 69 Ga> Percentage 71 Ga
<u>Step 2:</u> Calculate the abundance %
⇒Percentage of 71 Ga = X %
⇒Percentage of 69 Ga = 100 % - X %
The mass balance equation will be:
100*69.72 = x * 71 + (100 - x)*69
6972 = 71x + 6900 -69x
72 = 2x
x = 36 %
71 Ga has a naturally abundance of 36%
69 Ga has a naturally abundance of 64%
Answer: 0.9375 g
Explanation:
To calculate the number of moles for given molarity, we use the equation:
.....(1)
Molarity of solution = 0.75 M
Volume of solution = 25.0 mL = 0.025 L
Putting values in equation 1, we get:
According to stoichiometry :
2 moles of require = 1 mole of
Thus 0.01875 moles of will require= of
Mass of
Thus 0.9375 g of is required to react with 25.0 ml of 0.75 M HCl
If you have 58.93g of Co it means that you only have 1 mol (use a periodic table to find the answer, if you had more find it by proportion, it's easier).
There's 6.022 x 10^23 atoms per mol so you have 6.022 x 10^23 atoms of Co.
(once again if you had more mol, you could find the answer by proportions).
0.78 is what the verified answer says
Answer:
transfer pipet that had markings every 0.1 mL.
Explanation: