Answer:
Halogens
Explanation:
From the given choices, the halogens will have the smallest radius within the same period.
The size of an atom is estimated by the atomic radius. This is taken as half of the inter-nuclear distance between two covalently bonded atoms of non-metallic elements or half of the distance between two nuclei in the solid state.
- Across a period in the periodic table, atomic radii decrease progressively from left to right.
- Down a group from top to bottom, atomic radii increase progressively due to the addition of successive shells.
Since halogen is the right most group from the choices given, it will have the smallest radius.
Answer:
Final temperature = T₂ = 155.43 °C
Explanation:
Specific heat capacity:
It is the amount of heat required to raise the temperature of one gram of substance by one degree.
Formula:
Q = m.c. ΔT
Q = amount of heat absorbed or released
m = mass of given substance
c = specific heat capacity of substance
ΔT = change in temperature
Given data:
Mass of coin = 4.50 g
Heat absorbed = 54 cal
Initial temperature = 25 °C
Specific heat of copper = 0.092 cal/g °C
Final temperature = ?
Solution:
Q = m.c. ΔT
ΔT = T₂ -T₁
Q = m.c. T₂ -T₁
54 cal = 4.50 g × 0.092 cal/g °C × T₂ -25 °C
54 cal = 0.414 cal/ °C × T₂ -25 °C
54 cal /0.414 cal/ °C = T₂ -25 °C
130.43 °C = T₂ -25 °C
130.43 °C + 25 °C = T₂
155.43 °C = T₂
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.
