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Chemistry LibreTexts

Homework 56

  • Page ID
    28970
  • Question 9.41:

    A) Which of the following compounds are soluble?

    a.

    b.

    c.

    d.

    B) Determine the ions that break up from the the soluble compound in a solution.

    Solution:

    A)

    a. soluble: Based on solubility rules, is always soluble. There are no exceptions. Therefore, this aqueous compound will ionize and break into ions.

    b. soluble: Based on solubility rules, any compound containing is soluble and will break into ions. is also always soluble.

    c. soluble: Based on solubility rules, is generally insoluble. However, is an exception to this rule. Since this compound contains , it will break into ions.

    d. insoluble: Based on the solubility rules, is generally insoluble. is not an exception to this rule. Therefore, this compound will form a solid (or a precipitate) and will not break into ions.

    B)

    a.

    b.

    c.

    d. This compound does not break into ions. Instead, since it is insoluble, it is a precipitate and is a solid.

    Question 10.55:

    After a complete reaction of 6.50kg of , how much heat formed?

    Solution:

    Step 1: Is the equation balanced? Yes. Also note that there is 1 mol of in this reaction. There are 2 mol of in this reaction. There is 1 mol of in this reaction. There are 2 mol of in this reaction.

    Step 2: What is given? We know that there is 6.50kg of .

    We know that

    Step 3: What other conversion factors might be useful to solve this problem?

    1,000g=1kg

    The molar mass of =16.05g/mol (Use the periodic table to locate the molar mass for and . Multiply the molar mass of hydrogen by 4. Add this number, 4.04g/mol, to the molar mass of ,12.01g/mol.)

    Step 4: Set up dimensional analysis, starting with the value given in the question. (Make sure that your units "match" when completing this step.

    The negative sign indicates that this is an exothermic reaction. In other words, the system (the reactants) lost energy to the surroundings (the products) in the form of heat.

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