The question is missing the data sets.
This is the complete question:
A single penny has a mass of 2.5 g. Abbie and James
each measure the mass of a penny multiple times. Which statement about
these data sets is true?
O Abbie's measurements are both more accurate
and more precise than James'.
O Abbie's measurements are more accurate,
but less precise, than James'.
O Abbie's measurements are more precise,
but less accurate, than James'.
O Abbie’s measurements are both less
accurate and less precise than James'.
Penny masses (g)
Abbie’s data
2.5, 2.4, 2.3, 2.4, 2.5, 2.6, 2.6
James’ data
2.4, 3.0, 3.3, 2.2, 2.9, 3.8, 2.9
Answer: first option, Abbie's measurements are both more accurate
and more precise than James'.
Explanation:
1) To answer this question, you first must understand the difference between precision and accuracy.
<span>Accuracy is how close the data are to the true or accepted value.
</span>
<span>Precision is how close are the data among them, this is the reproducibility of the values.</span>
Then, you can measure the accuracy by comparing the means (averages) with the actual mass of a penny 2.5 g.
And you measure the precision by comparing a measure of spread, as it can be the standard deviation.
2) These are the calculations:
Abbie’s data
Average: ∑ of the values / number of values
Average = [2.5 + 2.4 + 2.3 + 2.4 + 2.5 + 2.6 + 2.6 ] / 7 = 2.47 ≈ 2.5
Standard deviation: √ [ ∑ (x - mean)² / (n - 1) ] = 0.11
James’ data
Average = [2.4 + 3.0 + 3.3 + 2.2 + 2.9 + 3.8 + 2.9] / 7 = 2.56 ≈ 2.6
Standard deviation = 0.53
3) Conclusions:
1) The average of Abbie's data are closer to the accepted value 2.5g, so they are more accurate.
2) The standard deviation of Abbie's data is smaller than that of Jame's data, so the Abbie's data are more precise.
Its b Fe(s) <span> Fe</span>2+(aq) + 2e– <span><span> </span>E</span><span> = </span><span>+0.44 V</span>
Answer is: There are more reactants and one product of the reaction. The reactants may be elements or compounds. The product is always a compound.
Synthesis reaction is a type of reaction in which multiple reactants combine to form a single product.
For example, balanced chemical reaction: Ba + F₂ → BaF₂.
In barium fluoride, barium has oxidation number +2 and fluorine has oxidation number -1, so compound has neutral charge.
Second chemical reaction: CaO(s) + H₂O(l) → Ca(OH)₂(aq).
One molecule is produced from two molecules.
Answer:
(a) 
(b) 
(c) 
(d) 
(e) 
Explanation:
To calculate de pH of an acid solution the formula is:
![pH = -Log ([H^{+}]) = 1](https://tex.z-dn.net/?f=pH%20%3D%20-Log%20%28%5BH%5E%7B%2B%7D%5D%29%20%3D%201)
were [H^{+}] is the concentration of protons of the solution. Therefore it is necessary to know the concentration of the protons for every solution in order to solve the problem.
(a) and (c) are strong acids so they dissociate completely in aqueous solution. Thus, the concentration of the acid is the same as the protons.
(b) and (e) are strong bases so they dissociate completely in aqueous solution too. Thus, the concentration of the base is the same as the oxydriles. But in this case it is necessary to consider the water autoionization to calculate the protons concentration:
![K_{w} =[H^{+} ][OH^{-}]=10^{-14}](https://tex.z-dn.net/?f=K_%7Bw%7D%20%3D%5BH%5E%7B%2B%7D%20%5D%5BOH%5E%7B-%7D%5D%3D10%5E%7B-14%7D)
clearing the ![[H^{+} ]](https://tex.z-dn.net/?f=%5BH%5E%7B%2B%7D%20%5D)
![[H^{+} ]=\frac{10^{-14}}{[OH^{-}]}](https://tex.z-dn.net/?f=%5BH%5E%7B%2B%7D%20%5D%3D%5Cfrac%7B10%5E%7B-14%7D%7D%7B%5BOH%5E%7B-%7D%5D%7D)
(d) is a weak base so it is necessary to solve the equilibrium first, knowing 
The reaction is 
→ 
so the equilibrium is
clearing the <em>x</em>
![x=[H^{+}]=4.93x10^{-10}](https://tex.z-dn.net/?f=x%3D%5BH%5E%7B%2B%7D%5D%3D4.93x10%5E%7B-10%7D)
Answer:
The answers are A,B,C.
Explanation: Just got it right on Edge 2020
