Nelson Science Perspectives 10
1st Edition
ISBN: 9780176355289
Textbook solutions
All Solutions
Section 7-3: The pH Scale
Exercise 1
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a ) pHs of less than 7 indicate acidity, whereas a pH of greater than 7 indicates a base.
b ) this topic was covered in 8th grade science
c ) my grandmother has a pool in her backyard and if the pH goes below 7 the water makes your eyes irritated
b ) this topic was covered in 8th grade science
c ) my grandmother has a pool in her backyard and if the pH goes below 7 the water makes your eyes irritated
Result
2 of 2
a ) pHs of less than 7 indicate acidity, whereas a pH of greater than 7 indicates a base.
b ) this topic was covered in 8th grade science
c ) my grandmother has a pool in her backyard and if the pH goes above 8 the water makes your eyes irritated
b ) this topic was covered in 8th grade science
c ) my grandmother has a pool in her backyard and if the pH goes above 8 the water makes your eyes irritated
Exercise 2
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a. pH of lemon juice is $2$.
Step 2
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b. pH of milk of magnesia is $10$.
Step 3
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c. pH of borax is $9$.
Result
4 of 4
a. 2
b. 10
c. 9
Exercise 3
Step 1
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a. A solution of pH $13$ is highly basic as it is greater than 7.
Step 2
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b. A solution of pH $6$ is slightly acidic as it is less than 7.
Step 3
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c. A solution of pH $1$ is highly acidic as it is less than 7.
Step 4
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d. The moisture on human skin is sweat which is salty in nature and therefore must be neutral.
Step 5
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e. pH of the water in swimming pools is strictly maintained between $7.2$ to 7.8.
Result
6 of 6
Click to see answers.
Exercise 4
Step 1
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a.
pH of baking soda is $8.3$, pH of tomatoes is $4$, pH of stomach acid is $1.5$, pH of bleach is $12$, pH of black coffee is $5$, and pH of pure water is $7$, therefore arranged in order of increasing acidity (or decreasing pH), the order becomes: bleach, baking soda, pure water, black coffee, tomatoes and stomach acid.
Step 2
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b.
The pH of substances in this order decreases as we move from left to right of the order.
The pH of substances in this order decreases as we move from left to right of the order.
Exercise 5
Step 1
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a.
Metal toxins in the soil are removed from it by the process of acid leaching. In this process, the affected soil is treated with acid to dissolve the metallic toxins in it.
Metal toxins in the soil are removed from it by the process of acid leaching. In this process, the affected soil is treated with acid to dissolve the metallic toxins in it.
Step 2
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b.
pH of a soil affects the crop yield planted in it. Therefore in accordance with the requirement of the plant the pH of the soil can be maintained to acidic, basic or neutral state. Aluminum sulfate can be used to reduce the pH of soil, while calcium oxide can be used to increase it.
pH of a soil affects the crop yield planted in it. Therefore in accordance with the requirement of the plant the pH of the soil can be maintained to acidic, basic or neutral state. Aluminum sulfate can be used to reduce the pH of soil, while calcium oxide can be used to increase it.
Step 3
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c.
pH of swimming pools is maintained between 7.2 to 7.8. Hydrochloric acid is used to decrease the pH of water if it gets too high while sodium carbonate is used to increase it. This prevents the growth of micro-organisms in swimming pools.
pH of swimming pools is maintained between 7.2 to 7.8. Hydrochloric acid is used to decrease the pH of water if it gets too high while sodium carbonate is used to increase it. This prevents the growth of micro-organisms in swimming pools.
Result
4 of 4
Click to see answers.
Exercise 6
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Household products must be stored in their original containers because these containers provide the best storage for these liquid as they are designed with the pH of these solutions in mind. If other containers are used, there is a likelihood that other containers might/will erode.
Exercise 7
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a ) garage, kitchen, and bathroom
Step 2
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b) Original Windex has ammonia as the main ingredient and has a pH of 10. 7. This means that it must be a fairly strong ammonia solution. Ammonia is a ‘weak’ base, Clorox bleach has pH of around 11 and making it mildly irritating to the skin, Concentrated bleach is highly alkaline (pH ~13) and now is now so corrosive that it can burn skin on contact.
Result
3 of 3
a ) garage, kitchen, and bathroom
b) Original Windex has ammonia as the main ingredient and has a pH of 10. 7.
Exercise 8
Solution 1
Solution 2
Step 1
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A pH of 7 is neutral, which means it is not acidic nor basic. Anything above that (7-14) is basic, and anything below that (0-6) is acidic.
When it comes to the skin, a pH of 5,5 is considered neutral. It is acceptable that a skin-care product’s pH varies between 4,5 and 7.
Result
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When it comes to the skin, a pH of 5,5 is considered neutral. It is acceptable that a skin-care product’s pH varies between 4,5 and 7.
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In this question we will be explaining what is the meaning of pH-balanced on skincare creams, and how is it related to the pH of our skin.
Step 2
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Firstly, our skin is considered acidic with a pH range between 4.0-6.0 and the majority of values are between 4.2 and 5.6.
Step 3
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The pH-balanced term on skincare creams means that the pH of the cream is close to the natural pH of our skin.
Exercise 9
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Metal toxins in the soil are removed from it by the process of phytoremediation. In this process, certain toxin absorbent plants are planted and as they grow, they absorb metal toxins from the soil. They are then harvested and burned completely. Their bodies are made up of metal toxins which can then be recovered from their ashes. This metal collected from ashes in no longer a toxin and can be put to better use via recycling and refining it. This is a more economical process than acid leaching as in acid leaching requires the removal of soil from its original location, treating and cleaning it and returning it to its original location. This is not only very expensive because of the cost of transport, commute and treatment but is detrimental to the ecosystem of the area. Many microorganisms, and other living beings of the soil die in this process sometimes rendering the soil to infertility unless it is artificially made fertile again.
Exercise 10
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In order to maintain a healthy mouth and teeth, low pH foods like carbonated drinks should be avoided. Sugar rich foods must also be avoided as traces of sugar left in the mouth convert to a weak acid which can be detrimental for teeth enamel. It is also recommended to brush your teeth so any traces of sugar in the mouth can be removed.
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