Gizmo Student Exploration: Periodic Trends Does anyone have the answer key?
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The powder could be acetaminophen, analgesic having chemical formula
A chemical formula showing the simplest ratio of elements in a compound rather than the total number of atoms in the molecule.
We are given:
Percentage of C = 67.31 %
Percentage of H = 6.978 %
Percentage of N = 4.617 %
Percentage of O = 21.10 %
Let the mass of the compound be 100 g. So, the percentages given are taken as mass.
Mass of C = 67.31 g
Mass of H = 6.978 g
Mass of N = 4.617 g
Mass of O = 21.10 g
To formulate the empirical formula, we need to follow some steps:
Step 1: Converting the given masses into moles.
Moles of carbon =
Moles of carbon =
=5.60 moles
Moles of hydrogen =
Moles of hydrogen =
=6.978 moles
Moles of nitrogen =
Moles of nitrogen =
=0.329 moles
Moles of oxygen =
Moles of oxygen =
=1.31 moles
Step 2: Calculating the mole ratio of the given elements.
For the mole ratio, we divide each value of the moles by the smallest number of moles calculated which is 0.329 moles.
We get the ratio of C : H : N : O = 17 : 21 : 1 : 4
The empirical formula for the given compound is .
Learn more about the empirical formula here:
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The density of a material is the mass of the material per unit volume. Here the weight of the same metal is 44.40g, 40.58g and 38.35g having volume 4.8 mL, 4.7 mL and 4.2 mL respectively. Thus the density of the metal as per the given data are, = 9.25g/mL,
= 8.634g/mL and
= 9.130g/mL respectively.
The equation of the standard deviation is √{∑(x - )÷N}
Now the mean of the density is {(9.25 + 8.634 + 9.130)/3} = 9.004 g/mL.
The difference of the density of the 1st metal sample (9.25-9.004) = 0.246 g/mL. Squaring the value = 0.060.
The difference of the density of the 2nd metal sample (9.004-8.634) =0.37 g/mL. Squaring the value = 0.136.
The difference of the density of the 3rd metal sample (9.130-9.004) = 0.126 g/mL. Squaring the value 0.015.
The total value of the squared digits = (0.060 + 0.136 + 0.015) = 0.211. By dividing the digit by 3 we get, 0.070. The standard deviation will be . Thus the standard deviation of the density value is 0.265g/mL.