Answer:
The atomic mass of gallium (Ga) = <u>69.723 g/mol</u>
Explanation:
Given: Two isotopes of Gallium (Ga) are Gallium-69 (⁶⁹Ga) and Gallium-71 (⁷¹Ga)
<u>For ⁶⁹Ga: </u>
Relative abundance = 60.12% = 60.12 ÷ 100 = 0.6012; Atomic mass = 68.9257 g/mol
<u>For ⁷¹Ga:</u>
Relative abundance = 39.88% = 39.88 ÷ 100 = 0.3988; Atomic mass = 70.9249 g/mol
∴ The atomic mass of Ga = (Relative abundance of ⁶⁹Ga × Atomic mass of ⁶⁹Ga) + (Relative abundance of ⁷¹Ga × Atomic mass of ⁷¹Ga)
⇒ Atomic mass of Ga = (0.6012 × 68.9257 g/mol) + (0.3988 × 70.9249 g/mol) = <u>69.723 g/mol</u>
<u>Therefore, the atomic mass of gallium (Ga) = 69.723 g/mol</u>
Ok first, we have to create a balanced equation for the dissolution of nitrous acid.
HNO2 <-> H(+) + NO2(-)
Next, create an ICE table
HNO2 <--> H+ NO2-
[]i 0.139M 0M 0M
Δ[] -x +x +x
[]f 0.139-x x x
Then, using the concentration equation, you get
4.5x10^-4 = [H+][NO2-]/[HNO2]
4.5x10^-4 = x*x / .139 - x
However, because the Ka value for nitrous acid is lower than 10^-3, we can assume the amount it dissociates is negligable,
assume 0.139-x ≈ 0.139
4.5x10^-4 = x^2/0.139
Then, we solve for x by first multiplying both sides by 0.139 and then taking the square root of both sides.
We get the final concentrations of [H+] and [NO2-] to be x, which equals 0.007M.
Then to find percent dissociation, you do final concentration/initial concentration.
0.007M/0.139M = .0503 or
≈5.03% dissociation.
Answer:
When the results of a new experiment to test atomic theory do not agree with the theory, scientist will repeat the experiment to make sure that his results are reliable.
Explanation:
In the scientific context, each new experiment must be performed with precision and following the steps of the scientific method.
An experiment that does not provide reliable data to demonstrate a theory must be reviewed in detail and performed again to confirm the data obtained in the first attempt.
A theory is a postulate that tries to explain a natural phenomenon, but whose argument can be discussed or does not have the acceptance of a law. When the theory is proven and there are no arguments against it, it can be universally accepted and becomes a law.
The other options are not valid due to:
- <u><em>Scientists worldwide will reject atomic theory because of the new results</em></u><em>. A theory cannot be discarded without solid arguments or evidence in order to dismiss it and establish a new one.</em>
- <u><em>The scientist will change his results to agree with the accepted theory</em></u><em>. This would be an unethical procedure and unacceptable to the scientific community.</em>
- <em><u>Other scientists will reject the results because they do not agree with the theory</u></em><em>. The opinion of other scientists is not enough to dismiss a theory, if it has a valid scientific basis.</em>