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CHE 375 F11 Homework 1(1)

# CHE 375 F11 Homework 1(1) - Normalize the numbers relative...

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CHE 375 Fall 11 Homework 1 Name: Some of the information required for this homework was not given in class. Find it in the literature, including sources on the web. List the sources: 1. Find the age of the following, convert to seconds, and express in scientific notation: Age in seconds Universe Earth Life on Earth One year 2. Find the total mass (of atomic matter) of the following and convert to hydrogen atom equivalents, i.e., calculate how many hydrogen atoms would have the same mass. Mass in grams Number of hydrogen atom equivalents Universe Solar system Earth Moon 3. Calculate the relative molar amounts from the mass %. Fill in the mass % from your class notes (or other sources). Calculate the number of moles contained in an imaginary 100 g sample. (This step is like the first step in establishing an empirical formula.)

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Unformatted text preview: Normalize the numbers relative to 100 atoms of the most abundant element. For example, in Table 3a, the result will be 100 hydrogen atoms, followed by about 10 helium atoms, etc. Table 3a. Abundance of Elements in Universe Element Mass % Number of moles in 100 g sample Normalized relative number of atoms H He O C N Ne Be Table 3b. Abundance of Elements in Earth’s Crust Element Mass % Number of moles in 100 g sample Normalized relative number of atoms O Si Al Fe Ca Na K Mg Ti H P Mn 4. Calculate the concentration (mmol/L) of from the mass percent for the following elements in sea water. (Note: I wrote mol/L on the board in the classroom. Let’s change that to mmol/L.) Assume the density of sea water to be 1.0 g/mL. Element Mass % mmol/L Cl 1.94 Na 1.08 Mg 0.13 S 0.09 Ca 0.04 K 0.04...
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CHE 375 F11 Homework 1(1) - Normalize the numbers relative...

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