Page 398 - Teacher Preview Copy

Constructed Response . Topic 7: Solutions

Set G: Molarity calculation, concentration of solution

Base your answers to questions 21 and 22 on the information below.

A student is instructed to make 0.250 liter of a 0.200 M aqueous solution of Ca(NO3)2.

21. In order to prepare the described solution in the laboratory, 21.
two quantit ies must be measured accurately. One of these

quantities is the volume of the solution. What other quantity
must be me asured to prepare this solution?

22. Show a correct numerical setup for calculating the total 22.

number of moles of Ca(NO3)2 needed to make 0.250 liter
Teacher Preview Copy
Teacher Preview Copy

of the 0.200 M calcium nitrate solution.

23. Show a correct numerical setup for determining how many 23.

liters of a 1.2 M solution can be prepared with 0.50 mole

of C6H12O6.

24. What is the concentration of a solution that contains 24.

2 moles of solute in 1.2 L of solution.

Set H: Solubility and energy, molecule-ion attraction, direction of heat flow

Given the balanced equation for the dissolving NH4Cl(s) in water:

H2O
-
+
NH4Cl(s) -------------------- > NH4 (aq) + Cl (aq)

25. A student is holding a test tube containing 5.0 milliliters 25.

of water. When a sample of NH4Cl(s) is placed in the test
tube, the test tube feels colder to the student’s hand.

Describe the direction of heat flow between the test tube

and the hand.

26.

26. Using the key to the right, draw at 26.

least two water molecules in the box

showing the correct orientation of each

water when it is near the Cl- ion in the

aqueous solution

388 Copyright © 2010 E3 Scholastic Publishing. All Rights Reserved. Survivingchem.com