Answer:
Answers are in the explanation
Explanation:
Precision and accuracy are both statistical concepts. Precision is about how close are the measured values to each other. Accuracy is closeness of the measured values to a specific value or reference value.
There are many ways to calculate precision and accuracy, one is stimating precision as <em>Relative Uncertainty </em>and accuracy as <em>Relative Error.</em>
Formulas are:
Relative Uncertainty: Standard desviation / Measured value.
Relative Error: Measured Value - Expected Value / Expected value
<em>Measured value is the aveage of the values.</em>
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For student 1:
Mean = 25
Standard desviation = 1.5275
Relative Uncertainty: 1.5275 / 25
Relative Uncertainty: 0.061
Relative Error: 25 - 20 / 20
Relative Error: 0.25
For student 2:
Mean = 24.5
Standard desviation = 0.5477
Relative Uncertainty: 0.5477 / 24.5
Relative Uncertainty: 0.02
Relative Error: 24.5 - 20 / 20
Relative Error: 0.225
<em>As the student 2 has a low Relative error and uncertainty, you can say student 2 is more accurate and precise</em>
Answer:
weighing balance/analytical balance
Graduated cylinder/buret
Explanation:
The mass of the evaporating basin could be measured using a weighing balance or an analytical balance. Both are classified as weighing scales but the analytical balance can measure the mass of objects up to 4 decimal places, thus, providing better accuracy in measurement than ordinary weighing balance that can only measure up to 2 decimal places.
In order to measure 50 cm3 of the sea water, a graduated cylinder or a buret can be used. Both equipment can measure up to the same decimal places and, thus, have virtually the same accuracy.
1) Chemical reaction: AgNO₃ + HCl → AgCl + HNO₃.
V(AgNO₃) = 30,0 mL = 0,03 L.
c(AgNO₃) = 0,225 mol/L.
n(AgNO₃) = 0,03 L · 0,225 mol/L.
n(AgNO₃) = 0,00675 mol.
From chemical reaction: n(AgNO₃) : n(HCl) = 1 : 1.
0,00675 mol : n(HCl) = 1 : 1.
n(HCl) = 0,00675 mol.
V(HCl) = n(HCl) ÷ c(HCl).
V(HCl) = 0,00675 mol ÷ 0,130 mol/L.
V(HCl) = 0,0519 L = 51,92 ml.
2) 1) Chemical reaction: AgNO₃ + KCl → AgCl + KNO₃.
V(AgNO₃) = 30,0 mL = 0,03 L.
c(AgNO₃) = 0,225 mol/L.
n(AgNO₃) = 0,03 L · 0,225 mol/L.
n(AgNO₃) = 0,00675 mol.
From chemical reaction: n(AgNO₃) : n(KCl) = 1 : 1.
0,00675 mol : n(KCl) = 1 : 1.
n(KCl) = 0,00675 mol.
m(KCl) = n(KCl) · M(KCl).
m(KCl) = 0,00675 mol · 74,55 g/mol.
m(KCl) = 0,503 g.
n - amount of substance.
M - molar mass.
In chemistry, the molar mass of a chemical compound is defined as the mass of a sample of that compound divided by the amount of substance in that sample, measured in moles.
Yes this is true otherwise it would not be a solution
