What are Hydrated Compounds? Hydrated Compounds are any compounds containing water in the form of H2O molecules, usually, but not always, with a definite content of water by weight. The hydrates are crystalline solids that lose their fundamental structures upon removal of the bound water. Anhydrides (meaning without water): A compound that is normally a hydrate and has lost its hydration water is said to be anhydrous and is called an anhydride. Hydrate vs. Anhydrate: Many ionic compounds can be used to soak up water. Before they absorb water, they’re referred to as which means water”. After absorbing “anhydrous”, “without water, they are hydrates. Cobalt chloride hexahydrate is an example. Hydration Number: Some compounds attach themselves to water molecules. This is done in set numbers, depending on the compound. For example, magnesium sulfate attaches to 7 molecules. We say its hydration number is 7. (Magnesium Sulfate Heptahydrate) MgSO4 x 7H2O Finding the Hydration Number: The hydration number can be conveniently found by heating the compound and measuring its mass loss. This mass loss is usually due to the hydration water molecules being driven off. Finding the Percent Hydrated Find the gram formula mass of the entire substance Find the gram formula mass of the the amount of only the water. The amount of water in grams divided by the amount gram formula mass times 100 is equal to the percent the substance is hydrated. gram-formula mass = 207, water = 36 → 36/207= .174 x 100= 17.4% Finding the Amount of Water a Substance Contains
What are Hydrated Compounds? Hydrated Compounds are any compounds containing water in the form of H2O molecules, usually, but not always, with a definite content of water by weight. The hydrates are crystalline solids that lose their fundamental structures upon removal of the bound water. Anhydrides (meaning without water): A compound that is normally a hydrate and has lost its hydration water is said to be anhydrous and is called an anhydride. Hydrate vs. Anhydrate: Many ionic compounds can be used to soak up water. Before they absorb water, they’re referred to as “anhydrous”, which means “without water”. After absorbing water, they are hydrates. Cobalt chloride hexahydrate is an example. Hydration Number: Some compounds attach themselves to water molecules. This is done in set numbers, depending on the compound. For example, magnesium sulfate attaches to 7 molecules. We say its hydration number is 7. (Magnesium Sulfate Heptahydrate) MgSO4 x 7H2O Finding the Hydration Number: The hydration number can be conveniently found by heating the compound and measuring its mass loss. This mass loss is usually due to the hydration water molecules being driven off. Finding the Percent Hydrated Find the gram formula mass of the entire substance Find the gram formula mass of the the amount of only the water. The amount of water in grams divided by the amount gram formula mass times 100 is equal to the percent the substance is hydrated. → gram-formula mass = 207, water = 36 36/207= .174 x 100= 17.4% Finding the Amount of Water a Substance Contains
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