Title: One of the chemicals used to make soaps is sodium hydroxide. Sodium hydroxide reacts with animal or vegetable fats to make glycerol and soap.
1- One of the chemicals used to make soaps is sodium
hydroxide. Sodium hydroxide reacts with animal or
vegetable fats to make glycerol and soap. - Sodium hydroxide belongs to a class of compounds
known as bases.
2Identifying Acids
- What are some general properties of acids?
- An acid is a compound that produces hydronium
ions (H3O) when dissolved in water.
Some general properties of acids include sour
taste, reactivity with metals, and ability to
produce color changes in indicators.
3Identifying Acids
- When hydrogen chloride gas dissolves in water, it
ionizes and forms hydronium ions and chloride
ions. - HCl H2O ? H3O Cl
- The solution that results is called hydrochloric
acid.
4Identifying Acids
5Identifying Acids
- Sour Taste
- Foods that taste sour often contain acids.
- Lemons, grapefruits, limes, and oranges contain
citric acid. - Vinegar contains acetic acid.
- Dairy products that have spoiled contain butyric
acid.
6Identifying Acids
- Reactivity With Metals
- The reaction between an acid and a metal is an
example of a single-replacement reaction. - When zinc is added to a test tube containing
hydrochloric acid, bubbles form in the tube. - Zn 2HCl ? H2 ZnCl2
7Identifying Acids
- Color Changes in Indicators
- An indicator is any substance that changes color
in the presence of an acid or base. - Litmus paper is made by coating strips of paper
with litmus, a kind of dye derived from lichens. - Blue litmus paper turns red in the presence of an
acid.
8Identifying Acids
- Apples contain several acids, including malic
acid, ascorbic acid (vitamin C), and citric acid. - Blue litmus paper is an indicator for acids.
9Identifying Bases
- What are some general properties of bases?
- A base is a compound that produces hydroxide ions
(OH) when dissolved in water.
Some general properties of bases include bitter
taste, slippery feel, and ability to produce
color changes in indicators.
10Identifying Bases
- Sodium hydroxide, NaOH, is an example of a base.
- When sodium hydroxide dissolves in water, it
dissociates into sodium ions and hydroxide ions. - NaOH ? Na OH
11Identifying Bases
- The plaster in this boys cast contains a base.
12Identifying Bases
- Bitter Taste
- Without sugar, chocolate tastes bitter. Cacao
beans contain a base that gives unsweetened
chocolate its bitter taste. - Many liquid medicines contain bases. Fruit
flavorings are often added to mask the taste of
these basic solutions.
13Identifying Bases
- Slippery Feel
- Bases feel slippery. Wet soap and many cleaning
products that contain bases are slippery to the
touch. - When wet, some rocks feel slippery because the
water dissolves compounds trapped in the rocks,
producing a basic solution.
14Identifying Bases
- Color Changes in Indicators
- Bases turn red litmus paper blue.
- Phenolphthalein is another acid-base indicator.
- In a solution containing a base, phenolphthalein
is red. - In a solution containing an acid, phenolphthalein
is colorless.
15Identifying Bases
- These hydrangea flowers contain natural
indicators. The color of the flowers depends on
whether the plant is growing in acidic or basic
soil. - When hydrangeas grow in acidic soil, the flowers
are bluish-purple. When hydrangeas grow in basic
soil, the flowers are pink.
16Neutralization and Salts
- What are the products of neutralization?
- The reaction between an acid and a base is called
neutralization.
The neutralization reaction between an acid and a
base produces a salt and water.
17Neutralization and Salts
- The negative ions in an acid combine with the
positive ions in a base to produce an ionic
compound called a salt. - The hydronium ions from the acid combine with the
hydroxide ions from the base to produce water.
18Neutralization and Salts
- When hydrochloric acid reacts with sodium
hydroxide, a neutralization reaction occurs. - If you let the water in the resulting solution
evaporate, sodium chloride would crystallize out
of solution.
19Neutralization and Salts
- Table salt is the most common example of a salt
compound. - Baking soda, NaHCO3, is produced during the
neutralization reaction between sodium hydroxide
and carbonic acid, H2CO3. - The ocean contains many dissolved salts,
including chlorides and sulfates of potassium,
calcium, magnesium, and sodium.
20Neutralization and Salts
- The common salts listed in the table can all be
made by reacting an acid with a base.
21Proton Donors and Acceptors
- What are proton donors and proton acceptors?
Acids can be defined as proton donors, and bases
can be defined as proton acceptors.
22Proton Donors and Acceptors
- When an acid and a base react in water, a proton
from the hydronium ion from the acid combines
with the hydroxide ion (OH) from the base to
form water (H2O). - Acids lose, or donate, protons. Bases accept
protons, forming water, a neutral molecule. This
definition allows you to classify a wider range
of substances as acids or bases.
23Proton Donors and Acceptors
- Based on the definitions of acids and bases that
you read earlier in this section, water is
neither an acid nor a base. - Using the proton-donor or proton-acceptor
definition, water can act as either an acid or a
base.
24Proton Donors and Acceptors
- When hydrogen chloride dissolves, water acts as a
base. It accepts a proton from hydrogen chloride
and becomes a hydronium ion.
25Proton Donors and Acceptors
- When hydrogen chloride dissolves, water acts as a
base. It accepts a proton from hydrogen chloride
and becomes a hydronium ion.
26Proton Donors and Acceptors
- When hydrogen chloride dissolves, water acts as a
base. It accepts a proton from hydrogen chloride
and becomes a hydronium ion.
27Proton Donors and Acceptors
- When ammonia dissolves, water acts as an acid. It
donates a proton to the ammonia, which acts as a
base.
28Proton Donors and Acceptors
- When ammonia dissolves, water acts as an acid. It
donates a proton to the ammonia, which acts as a
base.
29Proton Donors and Acceptors
- When ammonia dissolves, water acts as an acid. It
donates a proton to the ammonia, which acts as a
base.
30Assessment Questions
- What ion is formed when a base dissolves in
water? - hydroxide ion
- hydronium ion
- hydrogen ion
- sodium ion
31Assessment Questions
- What ion is formed when a base dissolves in
water? - hydroxide ion
- hydronium ion
- hydrogen ion
- sodium ionANS A
32Assessment Questions
- What products are formed in a neutralization
reaction? - an acid and a base
- water and a proton
- a base and a salt
- water and a salt
33Assessment Questions
- What products are formed in a neutralization
reaction? - an acid and a base
- water and a proton
- a base and a salt
- water and a saltANS D
34Assessment Questions
- In the reaction between ammonia and water to form
an ammonium ion, water acts as a(n) - acid because it donates an electron to ammonia.
- base because it donates an electron to ammonia.
- acid because it donates a proton to ammonia.
- base because it donates a proton to ammonia.
35Assessment Questions
- In the reaction between ammonia and water to form
an ammonium ion, water acts as a(n) - acid because it donates an electron to ammonia.
- base because it donates an electron to ammonia.
- acid because it donates a proton to ammonia.
- base because it donates a proton to
ammonia.ANS C
36Assessment Questions
- A food that contains acidic compounds can often
be identified by its bitter taste.TrueFalse
37Assessment Questions
- A food that contains acidic compounds can often
be identified by its bitter taste.TrueFalse - ANS F, sour