Crystal of table salt

View crystals of table salt with a magnifying glass or, better yet, a microscope if one is available. If you do have a microscope, crush the crystals with a spoon and examine the resulting powder. Purchase some... 

An ionic compound typically contains a multitude of ions grouped together in a highly ordered three-dimensional array. In sodium chloride, for example, each sodium ion is surrounded by six chloride ions and each chloride ion is surrounded by six sodium ions (Figure 6.11). Overall there is one sodium ion for each chloride ion, but there are no identifiable sodium-chloride pairs. Such an orderly array of ions is known as an ionic crystal. On the atomic level, the crystalline structure of sodium chloride is cubic, which is why macroscopic crystals of table salt are also cubic. Smash a large cubic sodium chloride crystal with a hammer, and what do you get Smaller cubic sodium chloride crystals Similarly, the crystalline structures of other ionic compounds, such as calcium fluoride and aluminum oxide, are a consequence of how the ions pack together. 

Many common substances are ionic in nature. This means that the atoms are in the form of charged particles, ions, and are arranged in a potentially huge spatial array that may have no fixed size. In such cases, the formula indicates the relative number of each element present. Table salt is composed of sodium and chloride ions (chlorine ions are called chloride ions) in close association. Although the size of a crystal of table salt is not fixed, the ratio of sodium to chloride ions is 1 1 then, the formula for table salt is expressed as NaCl. 

Take a small spatula and clean the tip by holding it in a Bunsen burner flame until the yellow color disappears. Allow to cool but do not let the tip touch anything. Place a few crystals of table salt on the clean spatula tip and heat in the flame of the Bunsen burner. Record your observation (2). 

It is customary to say that under the same external conditions all specimens of a particular substance have the same specific physical properties (density, hardness, color melting point, crystalline form, etc.). Sometimes, however, the word substance is used in referring to a material without regard to its state of aggregation for example, ice, liquid water, and water vapor may be referred to as the same substance. Moreover, a specimen containing crystals of rock salt and crystals of table salt may be called a mixture, even though the specimen may consist entirely of the one chemical substance sodium chloride. This lack of definiteness in usage seems to cause no confusion in practice. 

Hydration allows water-soluble chemicals to dissolve in water For example, a crystal of table salt (NaCl) is held together by strong ionic interactions. However, when NaCl is dissolved in water, the Na and Cl ions become independent hydrated entities. The energy produced by hydration of the Na and Cl ions more than balances the energy required to remove them from the NaCl crystal lattice. In the Na ion, a lone pair of electrons from a water oxygen atom fills an empty... 

However, the attractions between the ions in a salt do not stop with a single cation and a single anion. These forces are so far reaching that one cation attracts several different anions. At the same time, each anion attracts several different cations. In this way, many ions are pulled together into a tightly packed structure. The tight packing of the ions causes any salt, such as sodium chloride, to have a distinctive crystal structure. The smallest crystal of table salt that you could see would still have more than a billion billion sodium and chloride ions. 

Recall that the smallest crystal of table salt that you could see contains many billions of sodium and chloride ions all held together by ionic bonds. However, if you could look closely enough into the salt, all you would see are many Na" and Cl ions all bonded together to form a crystal. There are no NaCl molecules. 

Q The mass of one lime would be one-twelfth the mass of one dozen limes. In a crystal of table salt (sodium chloride), each sodium ion is surrounded by chloride ions, yet the ratio of sodium ions to chloride ions is one one. The formula for sodium chloride is NaCI. 

A solid is a form of matter that has a definite shape and volume. The small particles that make up a solid (atoms or molecules) are strongly attracted to one another, are touching, and are held rigidly in place. Solids cannot be compressed to a smaller volume. The highly organized arrangement of the particles in solids is why many of them are crystalline with definite geometric shapes, like the crystals of table salt. 

Although crystals of table salt (sodium chloride) and table sugar (sucrose) look very similar to the naked eye, the melting point of sucrose (186 "C) is several hundred degrees less than the melting point of sodium chloride (801 C). Explain. 

A large crystal of table salt. A salt crystal is composed of a three-dimensional array of particles. 

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