B is the answer
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Answer:
There is 30.74% of carbon in dimethylsulfoxide
Answer:
Options B and C
Explanation:
Let's take a look at the options and get our answer by way of elimination. The basic definition of a neutral solution is given as;
A neutral solution is a substance which is neither acid nor basic . it has a PH of 7. it will have equal amount of H+ AND OH- ions in it.
a) a neutral solution does not contain any H3O+ or OH- This is wrong because take water as an example, it is neutral but contains both ions.
b) a neutral solution contains [H2O] = [H3O+]. This option is correct cause it is in line with the definition above.
c) an acidic solution has [H3O⁺] > [OH⁻]. Acidic solutions are any solution that has a higher concentration of hydrogen ions than water. This option is correct.
d) a basic solution does not contain any H3O⁺. This option is wrong. Basic solutions are any solution that has a higher concentration of hydroxide ions than water. This means they contain H3O⁺ but [OH⁻] is greater.
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.
