Question

In: Chemistry

Propose a reasonable explanation for why soaps form scums with ions like Ca2+ but not with...

Propose a reasonable explanation for why soaps form scums with ions like Ca2+ but not with Na+. Support your explanation

Solutions

Expert Solution

I have always thought one aspect contributing to this behavior is the fact that the divalent Ca2+ and Mg2+ bind two soap fatty acid molecules, whereas Na1+ and K+ as monovalent ions can only strongly bind one molecule.

As a result, the alkaline earth cations have two fatty acid "tails" that can 'glom' around them, shielding them better from the water molecules and making the resulting complex more stable, as well as less soluble.

On the other hand, since the alkali cations only have one fatty acid "tail" they're strongly associated with, that one tail can't wrap around nearly as completely, and so there is significantly greater accessibility of the solvent to the cation.


Related Solutions

Synthesis of soap from lipids lab 1. Propose a reasonable explanation for why soaps form scums...
Synthesis of soap from lipids lab 1. Propose a reasonable explanation for why soaps form scums with ions like Ca2+ but not with Na+. 2. Compare the previous results with the test with tap water. Do you believe you have hard or soft water in your area?
Which would be the best emulsifier of soil if soft water (no Ca2+ ions, Mg2+ ions,...
Which would be the best emulsifier of soil if soft water (no Ca2+ ions, Mg2+ ions, and so on) were used? a. A soap. b. A detergent. c. Both would be about the same. Explain your answer: ________________________________
Propose an explanation for why there are no predominantly-aquatic marsupials while there are many aquatic placentals...
Propose an explanation for why there are no predominantly-aquatic marsupials while there are many aquatic placentals (seals, whales, manatees, etc.)
(a) Just like the familiar liquid solutions, two metal ions or atoms combine to form solid...
(a) Just like the familiar liquid solutions, two metal ions or atoms combine to form solid solution. What are substitutional solid solutions and interstitial solid solutions? Explain with examples and sketches. (b) How well the solid atoms combine to form solid solutions depends on how many of the Hume-Rothery rules have been violated or not violated. Describe Hume-Rothery rules?
Why do elements in group VI form -2 ions where as elements in group VII form...
Why do elements in group VI form -2 ions where as elements in group VII form -1 ions?
1. Which of the following ions will react with water in a hydrolysis reaction: Na+, Ca2+,...
1. Which of the following ions will react with water in a hydrolysis reaction: Na+, Ca2+, Cu2+, Zn2+, F-, SO32-, Br- 2. For those ions in question 1 that undergo hydrolysis, write net ionic equations for the hydrolysis reaction(s). 3. The Ka for HCN is 4.9x10-10. What is the value of Kb for CN-? Write the 2 equilibrium expressions and chemical equations. 4. What are the conjugate base and conjugate acid of H2PO4-? Look up the different Ka values for...
You are investigating the effects of ATP, Ca2+, and other ions on skeletal muscle contraction, and...
You are investigating the effects of ATP, Ca2+, and other ions on skeletal muscle contraction, and are conducting two experiments. First using glycerinated muscle, you can compare the ability of muscle to contract under 3 experimental conditions (1: ATP; 2: KCl+MgCl2; and 3: ATP+KCl+MgCl2). Second, using fresh muscle, you compare the ability of muscle to contract under another 3 experimental conditions (1: ATP; 2: Ca2+; and 3: ATP+Ca2+). For each experiment, what results would you expect regarding the amounts of...
A 0.6025 g sample was dissolved, and the Ca2+ and Ba2+ ions present were precipitated as...
A 0.6025 g sample was dissolved, and the Ca2+ and Ba2+ ions present were precipitated as BaC2O4·H2O and CaC2O4·H2O. The oxalates were then heated in a thermogravimetric apparatus leaving a residue that weighed 0.5713 g in the 320o-400oC range and 0.4673 g in the 580o-620oC range. Calculate the percentages of Ca and Ba in the original sample.
Suppose the mole number of Ca2+ ions in a 50 mL water sample is quantified as...
Suppose the mole number of Ca2+ ions in a 50 mL water sample is quantified as 1.5 × 10−5 mol. What is the concentration of Ca2+ ions in the water sample in ppm CaCO3?
Which of the following is false? a. Genetics is a reasonable explanation for the rise in...
Which of the following is false? a. Genetics is a reasonable explanation for the rise in obesity worldwide. b. The Cuban calorie crisis shows that restricting food choice can improve health c. Obesity has been rising because the typical job today is less physically strenuous than in the past d. The RAND Health Insurance Experiment found that more generous insurance does not make people fat.
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT