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| 1 | |
The empirical formula of a compound |
| | A) | is also known as the simplest formula |
| | B) | shows the lowest whole number ration of the elements in a compound |
| | C) | can be the same as the molecular formula |
| | D) | all of the above are true |
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| 2 | |
Which of the following is an empirical formula? |
| | A) | C3H6O2 |
| | B) | C2H6 |
| | C) | C2H2.5 |
| | D) | C2H6O2 |
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| 3 | |
Which statement is not true? |
| | A) | It is possible for different compounds to have the same empirical formula. |
| | B) | Compounds with the same empirical formulas have the same properties. |
| | C) | The empirical formula of an ionic compound is usually the same as its chemical formula. |
| | D) | An empirical formula may be the same as the molecular formula. |
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| 4 | |
What is the relationship between the subscripts of a molecular formula and those in an empirical formula (n is whole number)? |
| | A) | molecular formula subscripts = n x emiprical formula subscripts |
| | B) | empirical formula subscripts = n x molecular formula subscripts |
| | C) |  <![CDATA[<a onClick="window.open('/olcweb/cgi/pluginpop.cgi?it=gif::::/sites/dl/free/0070938539/128781/atlCHEMISTRY_CH03_QUIZ2_Q4c.gif','popWin', 'width=NaN,height=NaN,resizable,scrollbars');" href="#"><img valign="absmiddle" height="16" width="16" border="0" src="/olcweb/styles/shared/linkicons/image.gif"> (1.0K)</a>]]> |
| | D) |  <![CDATA[<a onClick="window.open('/olcweb/cgi/pluginpop.cgi?it=gif::::/sites/dl/free/0070938539/128781/atlCHEMISTRY_CH03_QUIZ2_Q4d.gif','popWin', 'width=NaN,height=NaN,resizable,scrollbars');" href="#"><img valign="absmiddle" height="16" width="16" border="0" src="/olcweb/styles/shared/linkicons/image.gif"> (1.0K)</a>]]> |
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| 5 | |
You are calculating an empirical formula and arrive at an answer of C1H2.67. What do you do next? |
| | A) | Nothing. The answer is acceptable. |
| | B) | Start over. You have obviously made a mistake. |
| | C) | Convert 2.67 to  <![CDATA[<a onClick="window.open('/olcweb/cgi/pluginpop.cgi?it=gif::::/sites/dl/free/0070938539/128781/atlCHEMISTRY_CH03_QUIZ2_Q5cd.gif','popWin', 'width=NaN,height=NaN,resizable,scrollbars');" href="#"><img valign="absmiddle" height="16" width="16" border="0" src="/olcweb/styles/shared/linkicons/image.gif"> (0.0K)</a>]]>
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| | D) | Convert 2.67 to <![CDATA[<a onClick="window.open('/olcweb/cgi/pluginpop.cgi?it=gif::::/sites/dl/free/0070938539/128781/atlCHEMISTRY_CH03_QUIZ2_Q5cd.gif','popWin', 'width=NaN,height=NaN,resizable,scrollbars');" href="#"><img valign="absmiddle" height="16" width="16" border="0" src="/olcweb/styles/shared/linkicons/image.gif"> (0.0K)</a>]]> and multiply both subscripts by 3 to get the lowest whole number subscript.
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| 6 | |
In order to calculate an empirical formula you need to know |
| | A) | the percent composition data |
| | B) | the molar mass of the elements |
| | C) | the molar mass of the compound |
| | D) | percentage composition data and the molar mass of the elements |
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| 7 | |
When calculating the empirical formula of a compound that is 32.3% Ca, 33.3% P and 34.4% O, for simplicity's sake, in the first step assume that you have |
| | A) | 1 mol of the compound |
| | B) | 50 g of the compound |
| | C) | 100 g of the compound |
| | D) | 100 mol of the compound |
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| 8 | |
In the above question, you determine that the elements are present in the molar ratio of Ca - 0.8059, P - 1.075 and O - 2.150. What is the empirical formula? |
| | A) | Use the calculated ratios as subscripts. The empirical formula is C0.8059P11.075O2.150. |
| | B) | Round the ratios to the nearest whole number and use as subscripts. The empirical formula is CPO2. |
| | C) | Divide the molar amounts by the smallest one and use the quotients as the subscripts. The empirical formula is CP1.32O2.67. |
| | D) | Divide the molar amounts by the smallest one. Multiply each by 3 to obtain whole numbers. The empirical formula is C3P4O8. |
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