Oxides and Hydroxides Of Alkaline Earth Metals
Oxides
All alkaline earth metals can react with oxygen (in the air) to form oxide compounds. Oxides formed by the alkaline earth metal are generally normal oxide compounds (MO). However, barium (Ba) can also form peroxide compounds (BaO2). This is because barium has the smallest charge density among all the alkaline earth metals.
All alkaline earth metal oxides are solid at room temperature.
All normal oxides of alkaline earth metals dissolve in water, except magnesium oxide, which is insoluble in water.
The alkaline earth metal oxide reacts with water to form a suitable hydroxide compound. For example, strontium oxide (SrO) reacts with water to form strontium hydroxide.
SrO (s) + H2O (l) ==> Sr (OH) 2 (s)
Magnesium Oxide
MgO is a compound that has a super high melting point, 2825 degrees Celsius. Compounds or materials that have a super high boiling point are often referred to as "refractory compounds". Because the melting point is very high, magnesium oxide is often used as a coating material in the furnace industry (a furnace that can produce heat with high temperatures).
The solid of magnesium oxide has unique properties. This compound is a good conductor of heat, but very bad in conducting electrical current. Typically, materials that can conduct heat, can also conduct electricity.
Because of its unique properties, magnesium oxide is used to make components on the electric stove. The magnesium can conduct good heat but does not conduct electricity to the exterior of the stove. So, we can cook quietly, without worrying about electric shock.
Calcium Oxide
Calcium oxide is often also called quicklime, with the chemical formula CaO. Calcium oxide is made by heating the calcium carbonate at a very high temperature (more than 1170 degrees Celsius).
CaCO3 (s) ==> CaO (s) + CO2 (g)
Calcium oxide is widely used in steel making industry.
Calcium oxide has a very high melting point. However, if our calcium oxide solids are burned (with flame), it will burn to produce a bright white flame. This phenomenon is called thermoluminescence.
In the past, before the introduction of electric light, theater players used calcium oxide solids to produce light effects on the stage.
As one of the normal oxides of alkaline earth metals, calcium oxide reacts with water to form a strong base, calcium hydroxide.
CaO (s) + H2O (l) ==> Ca (OH) 2 (s)
Ca (OH) 2 is often also called lime hydrate (a lime compound that binds water molecules). This compound is powdered and is often used to neutralize acidic soil pH. However, since calcium hydroxide is a strong base, its addition to the soil actually makes its pH change to a base.
To overcome this, calcium hydroxide is replaced by a safer ground-based calcium carbonate (CaCO3) powder.
Hydroxides
Here is a hydroxide compound formed by an alkaline earth metal.
Mg (OH) 2
Ca (OH) 2
Sr (OH) 2
Ba (OH) 2
Magenta hydroxide is insoluble in water. Calcium and strontium hydroxide is quite soluble in water while barium hydroxide is very soluble in water.
Although magnesium hydroxide is insoluble in water, it is beneficial. Magnesium hydroxide is the ingredient of heartburn drug, often called antacid. Someone who has heartburn disease has a lot of hydrochloric acid in the stomach. This acid will make the stomach feel so sore.
To neutralize the acid in the stomach, we need to consume a base.
Why use magnesium hydroxide?
Consume a strong base (easy to dissolve in water), will not cure heartburn disease. This is because hydroxide ions in high concentrations are very harmful to the human body. Magnesium hydroxide is a weak base which is only slightly soluble in water.
So, when we consume it, a number of hydroxide ions are not too much so it is safe for the stomach and certainly can neutralize the acid in the stomach.
All alkaline earth metals can react with oxygen (in the air) to form oxide compounds. Oxides formed by the alkaline earth metal are generally normal oxide compounds (MO). However, barium (Ba) can also form peroxide compounds (BaO2). This is because barium has the smallest charge density among all the alkaline earth metals.
All alkaline earth metal oxides are solid at room temperature.
All normal oxides of alkaline earth metals dissolve in water, except magnesium oxide, which is insoluble in water.
The alkaline earth metal oxide reacts with water to form a suitable hydroxide compound. For example, strontium oxide (SrO) reacts with water to form strontium hydroxide.
SrO (s) + H2O (l) ==> Sr (OH) 2 (s)
Magnesium Oxide
MgO is a compound that has a super high melting point, 2825 degrees Celsius. Compounds or materials that have a super high boiling point are often referred to as "refractory compounds". Because the melting point is very high, magnesium oxide is often used as a coating material in the furnace industry (a furnace that can produce heat with high temperatures).
The solid of magnesium oxide has unique properties. This compound is a good conductor of heat, but very bad in conducting electrical current. Typically, materials that can conduct heat, can also conduct electricity.
Because of its unique properties, magnesium oxide is used to make components on the electric stove. The magnesium can conduct good heat but does not conduct electricity to the exterior of the stove. So, we can cook quietly, without worrying about electric shock.
Calcium Oxide
Calcium oxide is often also called quicklime, with the chemical formula CaO. Calcium oxide is made by heating the calcium carbonate at a very high temperature (more than 1170 degrees Celsius).
CaCO3 (s) ==> CaO (s) + CO2 (g)
Calcium oxide is widely used in steel making industry.
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| Calcium Oxide Powdered. Image source: wikimediacommons.org |
In the past, before the introduction of electric light, theater players used calcium oxide solids to produce light effects on the stage.
As one of the normal oxides of alkaline earth metals, calcium oxide reacts with water to form a strong base, calcium hydroxide.
CaO (s) + H2O (l) ==> Ca (OH) 2 (s)
Ca (OH) 2 is often also called lime hydrate (a lime compound that binds water molecules). This compound is powdered and is often used to neutralize acidic soil pH. However, since calcium hydroxide is a strong base, its addition to the soil actually makes its pH change to a base.
To overcome this, calcium hydroxide is replaced by a safer ground-based calcium carbonate (CaCO3) powder.
Hydroxides
Here is a hydroxide compound formed by an alkaline earth metal.
Mg (OH) 2
Ca (OH) 2
Sr (OH) 2
Ba (OH) 2
Magenta hydroxide is insoluble in water. Calcium and strontium hydroxide is quite soluble in water while barium hydroxide is very soluble in water.
Although magnesium hydroxide is insoluble in water, it is beneficial. Magnesium hydroxide is the ingredient of heartburn drug, often called antacid. Someone who has heartburn disease has a lot of hydrochloric acid in the stomach. This acid will make the stomach feel so sore.
 |
| Source: flickr.com |
Why use magnesium hydroxide?
Consume a strong base (easy to dissolve in water), will not cure heartburn disease. This is because hydroxide ions in high concentrations are very harmful to the human body. Magnesium hydroxide is a weak base which is only slightly soluble in water.
So, when we consume it, a number of hydroxide ions are not too much so it is safe for the stomach and certainly can neutralize the acid in the stomach.
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