Chemical Reactions Quiz 1

Chemical Reactions Quiz 1 - with this number by...

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Chapter 5 CHEM 120 Chemical Reactions and Quantities Practice Quiz 1 Name ________________________________ 2pts 1. What is physical change? Give an example. A Physical change is one in which there is only a phase change (Example : solid to a liquid or liquid to a gas). There is no change in the chemical formula of the substance ; Example: Ice melting 2pts 2. How many mole of sulfate ions (SO 4 ) 2- are present in 3.5 moles of Al 2 (SO 4 ) 3 ? 1 mole Al 2 (SO 4 ) 3 2 moles Al 3 moles (SO 4 ) 2- 3.5 mole Al 2 (SO 4 ) 3 7 moles Al 10.5 moles (SO 4 ) 2- 2pts 3. What is Avagadro’s number? Just like a ‘dozen’ is 12 of anything, The ‘mole’ is 6.02 x 10 23 of anything. 6.02 x 10 23 is also called Avogadro’s number named after the Italian physicist Avogadro who came up
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Unformatted text preview: with this number by experimenting with C-12 atoms. It is used for expressing very large quantities by using a smaller number. Example 1 mole of C atoms is 6.02 x 10 23 C atoms 1 mole of H 2 O molecules is 6.02 x 10 23 H 2 O molecules 2pts 4. Calculate the mass in grams of 5 moles of NaCl. X grams NaCl = 5 moles NaCl x 58.45 g NaCl = 292.25 = 300 grams 1 mole NaCl ( you get 58.45 g by using the periodic table to find the masses of Na and Cl) 2pts 5. Balance the following equations N 2(g) + 3 H 2(g)------ > 2 NH 3(g) Pb(NO 3 ) 2 + 2 NaCl ----- > PbCl 2 + 2 NaNO 3...
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This test prep was uploaded on 04/10/2008 for the course CHEM 231 taught by Professor Hanover during the Spring '08 term at Lansing.

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