Group Assignment 1, 3 points Please submit one answer sheet for your group. A gr
ID: 575232 • Letter: G
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Group Assignment 1, 3 points Please submit one answer sheet for your group. A group is 2 or more students in the class. To receive full credit your work must be shown. 1. What is precision? Accuracy? Quantitatively, how is the precision and accuracy of an experiment determined? What is density and how will it be used in the Measurements Experiment? You are asked by the King of Allegesia to determine if the crown he was given for his birthday is pure gold. The density of pure gold is 19.32 g/mL; the density of water is 0.998 g/mL at 20°C. container is filled with water to the mark, it has a mass of 2499.5g. The crown is placed in the container and filled to mark with water and now weighs 15,113.3 g. The crown has a mass of 13,910.0 g. What is the density of the crown? Is the crown pure gold? There is a container when filled to mark contains 1900.0 mL. When the 3. Gold Coin Problem: A television advertisement is selling 24 carat replica gold coins at $9.99, which is a special from the normal price of $50.00. Listening carefully one discovers that it is not solid 24 K gold but is platted with 14 mg of 24 K gold. If gold costs $1,500. per ounce, how much is this company spending on the gold per coin? Please note that 24 K gold is 100% pure gold, whereas 12 K gold is 50.0% pure gold. . Accur acy is how close you get to tre stand or Pnown valye. Pre cis ian is naw ctose tvo or more meas ments art toExplanation / Answer
1. Precision and Accuracy: If the average value of different measurements is close to the correct value,the measurement is said to be accurate(individual measurements may not close to each other). If the values of different measurements are close to each other and hence closer to their average value, the measurement is said to be precise.
The degree of agreement between two or more replicate measurements made on a sample in an identical manner means exactly in the same fashion is known as precision of measurement.
Precision of a set of measurement is expressed in a number of ways:
1. Average deviation from the mean
2. Standard deviation
3. Relative Standard Deviation
Accuracy: The closeness of measurement or a set of measurments to the true or accpeted value .Accuracy is generally expressed in terms of absolute error and relative error.
Absolute Error in the measurement of quantity is expressed by the equation E= xi - xt where xi is the measured value and xt is the true(accepted ) value of a given measurment.
Relative Error: Er in a measurement is expressed in terms of xi - xt / xt
Precision and accuracy are distinctly different from each other.Accuracy is the measure of agreement between an experimental result and the true value of a given qunatity.Precision on other hand measures the agreement between several experimental results obtained from the same quantity under identical conditions.
Accuracy is expressed in terms of absolute error or relative error whereas precision is expressed in terms of various types of deviations from the mean.
Density is the mass of an object divided by its volume.
Determination of density: A density measurement involves the experimental determination of mass and volume of material,both of which introdcued an error in the final result,thus the contribution of each error must be determined as a part of any measurement.
Density is not something that is directly measured. Typically if you want to know the density of something you will weigh it and then measure its volume.
Density is a fundamental concept in the sciences; you will see it throughout your studies. It is used quite often in identifying rocks and minerals since the density of substances rarely changes significantly. For example, gold will always have a density of 19.3 g/cm3; if a mineral has a density other than that, it isn't gold.
If I have a rock that is made up of two minerals, one with a density of 2.8 g/cm3, and one with a density of 3.5 g/cm3, the rock will have a density between 3.5 and 2.8 g/cm3, not a density of 6.3 g/cm3. This is because both the mass and the volume of the two minerals will be added, and so when they are divided to get the density the result will be between the two.
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