Barium sulfate contains barium ions, Ba$^{2+}$ sulfate ions, SO$_4^{2-}$ (i) Give the formula of barium sulfate - Edexcel - GCSE Chemistry - Question 5 - 2013 - Paper 1

An ion is a charged particle, which can be either an atom or a molecule that has gained or lost electrons.

Barium sulfate is safe for the patient because it is insoluble in water. This means that once it is introduced into the body, it does not dissolve into the bloodstream or get absorbed by the body. Instead, it passes through the digestive system unchanged, allowing the X-ray to be taken without risking toxicity.

To prepare a pure, dry sample of barium sulfate, follow these steps:

1. Reactants Mixing: Dissolve barium chloride crystals in a beaker containing distilled water.
2. Add Sodium Sulfate: Slowly add sodium sulfate solution to the barium chloride solution while stirring to ensure thorough mixing.
3. Precipitate Formation: Barium sulfate will precipitate out of the solution.
4. Filtration: Use a filter funnel and filter paper to separate the solid barium sulfate from the liquid.
5. Washing: Wash the precipitate with distilled water to remove any impurities.
6. Drying: Allow the filter paper containing the barium sulfate to dry in a warm place, or leave it to air dry.

The balanced equation for the reaction between barium and chlorine is:

$\text{Ba} + \text{Cl}_2 \rightarrow \text{BaCl}_2$