Skip to main content
Ch.5 - Thermochemistry
Chapter 5, Problem 123a

Consider two solutions, the first being 50.0 mL of 1.00 M CuSO4 and the second 50.0 mL of 2.00 M KOH. When the two solutions are mixed in a constant-pressure calorimeter, a precipitate forms and the temperature of the mixture rises from 21.5 to 27.7 °C. (a) Before mixing, how many grams of Cu are present in the solution of CuSO4?

Verified step by step guidance
1
Determine the molarity of the CuSO_4 solution, which is given as 1.00 M.
Calculate the number of moles of CuSO_4 in the solution using the formula: \( \text{moles} = \text{molarity} \times \text{volume in liters} \).
Convert the volume from mL to L: 50.0 mL = 0.0500 L.
Calculate the moles of CuSO_4: \( 1.00 \text{ M} \times 0.0500 \text{ L} = 0.0500 \text{ moles of CuSO_4} \).
Determine the mass of Cu in the solution by using the molar mass of Cu (63.55 g/mol) and the stoichiometry of the reaction, knowing that 1 mole of CuSO_4 contains 1 mole of Cu.

Verified Solution

Video duration:
1m
This video solution was recommended by our tutors as helpful for the problem above.
Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Molarity and Moles

Molarity (M) is a measure of concentration defined as the number of moles of solute per liter of solution. To find the number of moles in a solution, you can multiply the molarity by the volume in liters. In this case, knowing the molarity of CuSO4 allows us to calculate the moles of copper present in the solution before mixing.
Recommended video:

Stoichiometry

Stoichiometry involves the calculation of reactants and products in chemical reactions. In the context of this question, understanding the stoichiometric relationships in the dissociation of CuSO4 is essential to determine how many moles of copper ions (Cu²⁺) are produced from the given moles of CuSO4, which directly relates to the mass of copper present.
Recommended video:
Guided course
01:16
Stoichiometry Concept

Precipitation Reactions

A precipitation reaction occurs when two solutions are mixed, resulting in the formation of an insoluble solid, or precipitate. In this scenario, the mixing of CuSO4 and KOH leads to the formation of copper(II) hydroxide (Cu(OH)₂), which is a precipitate. Understanding this concept helps in recognizing the significance of the reactants and products involved in the reaction.
Recommended video:
Guided course
01:53
Selective Precipitation
Related Practice
Textbook Question

Suppose an Olympic diver who weighs 52.0 kg executes a straight dive from a 10-m platform. At the apex of the dive, the diver is 10.8 m above the surface of the water. (a) What is the potential energy of the diver at the apex of the dive, relative to the surface of the water?

405
views
Textbook Question

Suppose an Olympic diver who weighs 52.0 kg executes a straight dive from a 10-m platform. At the apex of the dive, the diver is 10.8 m above the surface of the water. (b) Assuming that all the potential energy of the diver is converted into kinetic energy at the surface of the water, at what speed, in m>s, will the diver enter the water?

591
views
Textbook Question
Consider the following acid-neutralization reactions involving the strong base NaOH(aq): HNO31aq2 + NaOH1aq2¡NaNO31aq2 + H2O1l2 HCl1aq2 + NaOH1aq2¡NaCl1aq2 + H2O1l2 NH4+1aq2 + NaOH1aq2¡NH31aq2 + Na+1aq2 + H2O1l2 (d) In the third equation NH4 +1aq2 is acting as an acid. Based on the value of H° for this reaction, do you think it is a strong or a weak acid? Explain.
738
views
Open Question
The precipitation reaction between AgNO3(aq) and NaCl(aq) proceeds as follows: AgNO3(aq) + NaCl(aq) → NaNO3(aq) + AgCl(s). (b) What would you expect for the value of _x001F_H° of the overall molecular equation compared to that for the net ionic equation? Explain.
Textbook Question
A sample of a hydrocarbon is combusted completely in O21g2 to produce 21.83 g CO21g2, 4.47 g H2O1g2, and 311 kJ of heat. (a) What is the mass of the hydrocarbon sample that was combusted?
718
views
Textbook Question
The methane molecule, CH4, has the geometry shown in Figure 2.17. Imagine a hypothetical process in which the methane molecule is 'expanded,' by simultaneously extending all four C—H bonds to infinity. We then have the process CH41g2¡C1g2 + 4 H1g2 (a) Compare this process with the reverse of the reaction that represents the standard enthalpy of formation of CH41g2.
779
views