There are 30 protons and 39 neutrons in the nucleus.
This must me the isotope of an element with an atomic mass close to 69 u.
The only candidates are Zn and Ga.
Zn has a zinc-69 isotope with mass 68.926 u.
Ga has a gallium -69 isotope with mass 68.925 u.
The isotope is probably
.
It has 30 protons and 39 neutrons.
45 m. If each student needs 750 mm of tubing, the teacher should order 45 m of tubing.
a) Find the <em>length in millimetres</em>
Length = 60 students x (750 mm tubing/1 student) = 45 000 mm tubing
b) Convert <em>millimetres to metres
</em>
Length = 45 000 mm tubing x (1 m tubing/1000 mm tubing) = 45 m tubing
Answer:
2150 mmHg ( 1 atm / 760 mmHg ) ( 101.325 kPa / 1 atm ) = 286.643 kPa
Therefore, the closest value from the choices is the second one which has the value of 287, this would be answer.
Explanation:
I stole diss from someone else so Im juss hopin iss right
1.025 moles of NaCl are present in a solution with a molarity of 8.20M and 125 mL of solution. Details about molarity can be found below.
<h3>How to calculate molarity?</h3>
The number of moles of a solution can be calculated by multiplying the molarity of the solution by its volume. That is;
no of moles = molarity × volume
According to this question, a solution has a molarity of 8.20M and volume of 125 mL of solution.
no of moles = 8.20 × 0.125
no of moles = 1.025moles
Therefore, 1.025 moles of NaCl are present in a solution with a molarity of 8.20M and 125 mL of solution.
Learn more about number of moles at: brainly.com/question/14919968
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Answer:
pH of the solution = 9.45
Explanation:
pKb = 8.57
pKb = -logKb
Kb = antilog pkb
ICE table for the ionization of pyrodine is:
initial 0.435 0 0
equi. 0.435 - x x x
so,
![k_b =\frac{ [C_5H_5NH^+][OH^-]}{[C_5H_5N]}\\1.78\times 10^{-9}=\frac{x^2}{0.453 - x}](https://tex.z-dn.net/?f=k_b%20%3D%5Cfrac%7B%20%5BC_5H_5NH%5E%2B%5D%5BOH%5E-%5D%7D%7B%5BC_5H_5N%5D%7D%5C%5C1.78%5Ctimes%2010%5E%7B-9%7D%3D%5Cfrac%7Bx%5E2%7D%7B0.453%20-%20x%7D)
As kb is very less that means there is very less ionization, hence x can be ignored as compared to 0.435
pOH = -log[OH-]
![pOH = -log[2.78\times 10^{-5}]\\=4.55](https://tex.z-dn.net/?f=pOH%20%3D%20-log%5B2.78%5Ctimes%2010%5E%7B-5%7D%5D%5C%5C%3D4.55)
pH = 14 - pOH
= 14 - 4.55
= 9.45
