Chemistry Questions & Answers

18.9 g of fluorite \( \left(\mathrm{CaF}_{2}\right) \) reacts with excess sulfuric acid to form solid calcium sulfate and hydrogen fluoride gas that is collected at 695 . forr and \( 25.5{ }^{\circ} \mathrm{C} \). What gas temperature is required to store the gas in an 5.20 -L container at 809 . torr? Round your answer to 3 significant figures. Note: Reference the Fundamental constants table and Conversion factors for non-SI units the table for additional information.

A sample of an unknown gas effuses in 12.5 min . An equal volume of \( \mathrm{H}_{2} \) in the same apparatus under the same conditions effuses in 2.42 min . What is the molar mass of the unknown gas? Round your answer to 3 significant figures.

How many liters of gaseous hydrogen bromide at \( 35.0^{\circ} \mathrm{C} \) and 0.629 atm will a chemist need in order to prepare 3.50 L of 1.20 M hydrobromic acid? Round your answer to 3 significant figures. Note: Reference the Fundamental constants table for additional information.

3. \( \begin{array}{l}\text { (15 Points) Draw and classify the following alkyl halides as methyl-, primary } \\ \text { (I }) \text {, secondary }\left(\mathbf{L I}^{\circ}\right) \text {, or tertiary }\left(\mathbf{I I I}^{\circ}\right) \text { halide: } \\ \text {-2-chloro-3,3-dimethylhexane; }\end{array} \) -4-sec-butyl-2-chlorononane; -1-bromo-4-isopropylcyclohexane;

Xenon hexafluoride was one of the first noble gas compounds synthesized. The solid reacts rapidly with the silicon dioxide in glass or quartz containers to form liquid \( \mathrm{XeOF}_{4} \) and gaseous silicon tetrafluoride. What is the pressure in a \( 1.00-\mathrm{L} \) container at \( 25^{\circ} \mathrm{C} \) after 5.65 g of xenon hexafluoride reacts? (Assume that silicon tetrafluoride is the only gas present and that it occupies the entire volume.) Round your answer to 3 significant figures. Note: Reference the Fundamental constants table for additional information.

What is the effect of each of the following on the volume of 1 mol of an ideal gas? Part 1 of 2 The pressure changes from 760 torr to 1 atm , and the temperature changes from \( 37{ }^{\circ} \mathrm{C} \) to 155.15 K . Select the single best answer. Note: Reference the Conversion factors for non-SI units table for additional information. The volume increases by a factor of 2 . The volume increases by a factor of 4 . The volume decreases by a factor of 2 . The volume remains the same. Part 2 of 2 The temperature changes from 313.15 K to \( 40{ }^{\circ} \mathrm{C} \), and the pressure changes from 2 atm to 101 kPa . Select the single best answer. Note: Reference the Conversion factors for non-SI units table for additional information. The volume increases by a factor of 2 . Check 4 . The volume increases by a factor of 4 .

How many grams of potassium chlorate decompose to potassium chloride and \( 682 . \mathrm{mL} \) of \( \mathrm{O}_{2} \) at \( 128,{ }^{\circ} \mathrm{C} \) and 709 . torr? Round your answer to 3 significant figures. \( 2 \mathrm{KClO}_{3}(\mathrm{~s}) \rightarrow 2 \mathrm{KCl}(\mathrm{s})+3 \mathrm{O}_{2}(\mathrm{~g}) \) Note: Reference the Conversion factors for non-SI units and Fundamental constants tables for additional information.

After 0.600 L of Ar at 1.45 atm and \( 206.0^{\circ} \mathrm{C} \) is mixed with 0.200 L of \( \mathrm{O}_{2} \) at 374 . torr and \( 102.0^{\circ} \mathrm{C} \) in a \( 400 .-\mathrm{mL} \) flask at \( 24.0{ }^{\circ} \mathrm{C} \), what is the pressure in the flask? Round your answer to 3 significant figures. Note: Reference the Conversion factors for non-SI units, Fundamental constants and sI prefixes tables for additionat information.

A \( 26.3-\mathrm{g} \) sample of dinitrogen monoxide is confined in a \( 5.78-\mathrm{L} \) vessel. What is the pressure (in atm) at \( 119 .{ }^{\circ} \mathrm{C} \). Round your answer to 3 significant figures. Note: Reference the Fundamental constants table for additional information.

A 16.0 - g sample of dinitrogen monoxide is confined in a \( 3.93-\mathrm{L} \) vessel. What is the pressure (in atm) at \( 112 .{ }^{\circ} \mathrm{C} \). Round your answer to 3 significant figures. Note: Reference the Fundamental constants table for additional information.