The fundamentals Barium chromate is a chemical compound composed of two elements: barium (Ba) and chromate (CrO4). This compound is well known for its bright yellow color, making it easily recognizable in various applications.
In this post we will learn about the description of barium chromate, its formula, molar mass, separation and its importance in the field of science.
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Barium Chromate Formula
The chemical formula for barium chromate is BaCrO4.
We have:
Ba: The chemical symbol for barium.
CrO4: The chemical formula for the chromate ion, which consists of one chromium (Cr) atom bonded to four oxygen (O) atoms.
By combining these elements and ions, we get BaCrO4. This formula provides us with essential information about the compound's composition and structure.
Barium Chromate Molar Mass
That know the formula, let's delve into the molar mass of barium chromate. Molar mass is the mass of one mole of a substance and is expressed in grams per mole (g/mol). To calculate the molar mass of barium chromate, need to consider the individual atomic masses of its constituents.
1. Barium (Ba): 137.33 g/mol.
2. Chromium (Cr): 1.996 g/mol.
3. Oxygen (O): 15.999 g/mol,
But since there are four oxygen atoms in the chromate ion.
Multiply this by: 15.999 x 4 = 63.996 g/mol.
Now, calculate the molar mass of BaCrO4:
Molar Mass (BaCrO4) = Atomic Mass (Ba) + Atomic Mass (Cr) + Atomic Mass (Oxygen atoms in CrO4)
Molar Mass (BaCrO4) = 137.33 + 51.996 + 63.996
Molar Mass (BaCrO4) ≈ 253.322 g/mol
The molar mass of barium chromate (BaCrO4) is 253.322 g/mol.
Applications and Significance
The formula and molar mass of barium chromate is crucial for various applications. This compound finds utility in fields like chemistry, materials science, and industry.
It is commonly used in the production of pigments, as its vibrant yellow color adds aesthetic appeal to various products. Additionally, barium chromate plays a role in pyrotechnics, imparting a brilliant yellow hue to fireworks.
Barium Chromate Solubility
Barium chromate (BaCrO4) has limited solubility in water. It is considered sparingly soluble, which means that only a small amount of barium chromate will dissolve in water under normal conditions.
The solubility of barium chromate in water depends on temperature.
- At room temperature (around 25°C or 77°F), the solubility of barium chromate in water is quite low, typically less than 1 gram per liter (g/L).
- As you increase the temperature, the solubility of barium chromate also increases, meaning that more of it can dissolve in water. However, even at elevated temperatures, it remains relatively sparingly soluble.
It's important to note that the solubility of barium chromate can also be affected by the pH of the solution. In acidic conditions, it can be more soluble than in neutral or alkaline conditions.
Due to its limited solubility, barium chromate is often used as a solid reagent in various chemical reactions rather than in solution. If you need to work with barium chromate in solution, you may need to consider methods to increase its solubility, such as adjusting the pH or using solubilizing agents.
Barium Chromate Preparation
Preparing barium chromate involves a chemical reaction between barium chloride (BaCl2) and sodium chromate (Na2CrO4). Here's a step-by-step guide on how to prepare barium chromate:
Materials and Equipment
1. Barium chloride (BaCl2)
2. Sodium chromate (Na2CrO4)
3. Distilled water
4. Beakers
5. Stirring rod
6. Filtration apparatus (funnel and filter paper)
7. Glass stirring rod
8. Safety goggles and lab coat (for safety)
Procedure
1. Safety Precautions: Before you start, ensure you are wearing appropriate safety gear, including safety goggles and a lab coat, to protect yourself from any potential chemical splashes.
2. Weighing: Measure out the required amounts of barium chloride (BaCl2) and sodium chromate (Na2CrO4). The stoichiometric ratio for the reaction is 1:1, so you can use equimolar amounts.
For example: If you want to prepare a small amount, you can use 1 mole (137.33 g) of BaCl2 and 1 mole (161.97 g) of Na2CrO4.
3. Dissolution: Place the measured amounts of BaCl2 and Na2CrO4 into separate beakers. Add distilled water to each beaker to dissolve the compounds. Stir each solution until they are completely dissolved. Ensure that each solution is clear and homogeneous.
4. Combining Solutions: Slowly pour one of the solutions into the other while stirring continuously. As you mix the two solutions, a yellow precipitate of barium chromate (BaCrO4) should form. This reaction can be represented as:
BaCl2 (aq) + Na2CrO4 (aq) → BaCrO4 (s) + 2NaCl (aq)
5. Precipitation: Continue stirring for a few minutes to ensure complete precipitation of barium chromate.
6. Filtration: Set up a filtration apparatus (funnel and filter paper) to separate the solid barium chromate from the liquid. Pour the mixture into the funnel, and the yellow solid should be retained on the filter paper while the clear liquid (containing sodium chloride) passes through.
7. Washing: Wash the collected barium chromate on the filter paper with a small amount of distilled water to remove any residual impurities. Allow the washed barium chromate to dry on the filter paper.
8. Collection: Carefully remove the filter paper with the dried barium chromate from the funnel, and transfer the solid to a clean, dry container.
9. Drying: To ensure complete drying, you can place the container with the barium chromate in an oven at a low temperature, such as 60-70°C, until it is thoroughly dry.
10. Storage: Once dry, store the barium chromate in a labeled, airtight container in a cool and dry place. Be sure to handle it with care, as it is a potentially hazardous chemical.
That is barium compounds can be toxic and should be handled with caution. Additionally, proper lab safety protocols and waste disposal procedures should be followed when working with chemicals like barium chromate.
Barium Chromate Dissociation Equation
The dissociation equation for barium chromate (BaCrO4) in water can be represented as follows:
BaCrO4 (s) ⇌ Ba²⁺ (aq) + CrO4²⁻ (aq)
In this equation:
- BaCrO4 (s) represents solid barium chromate.
- Ba²⁺ (aq) represents the barium ions in aqueous solution.
- CrO4²⁻ (aq) represents the chromate ions in aqueous solution.
This equation illustrates the dissolution of solid barium chromate in water, resulting in the formation of barium ions (Ba²⁺) and chromate ions (CrO4²⁻) in the aqueous solution.
Barium Chromate Precipitate
Barium chromate (BaCrO4) is known for its limited solubility in water, which means that it can form a yellow precipitate when dissolved in certain conditions. The formation of this precipitate can be explained by its solubility product (Ksp), which is a measure of the maximum amount of a sparingly soluble salt that can dissolve in water before a solid precipitate begins to form.
The solubility product expression for barium chromate is as follows:
Ksp = [Ba²⁺] * [CrO4²⁻]
When the product of the concentrations of barium ions (Ba²⁺) and chromate ions (CrO4²⁻) in a solution exceeds the Ksp value for barium chromate, a precipitate of barium chromate will form. This is because the solution has become saturated with the ions, and any further addition of the compound will result in the excess forming a solid.
In simple terms, if you mix solutions containing barium ions (e.g., from a soluble barium salt) and chromate ions (e.g., from a soluble chromate salt) in the right proportions, a yellow precipitate of barium chromate will appear when the Ksp is exceeded.
