Pure Substances vs. Mixtures Salt and Water
Pure Substance vs. Mixture • Salt (sodium chloride) is a pure substance. • Distilled water (HOH) is a pure substance. • Salt in water is a special mixture called a solution. • What properties of water and salt allow them to mix so well? Check out the animation at Iowa State University. • Animation of Salt in Water
Challenge • Using a mesh screen, funnel and stand, coffee filter, two cups and water, separate a mixture of gravel, sand, and salt based on the properties of each substance. • Write down your procedure.
Solution to Challenge • Place the coffee filter in the funnel. • Place the mesh screen over the top of the funnel. • Place a cup under the funnel. • Pour the sand, gravel, salt mixture onto the mesh screen. • Go to next slide.
Solution to Challenge • The size of the gravel keeps it from going through the mesh screen. Pour the gravel into a small plastic bag. • Pour water over the sand and salt that are in the coffee filter. • Salt will dissolve in water and pass through the coffee filter. Sand will remain in the coffee filter. • Go to next slide.
Solution to Challenge • Set the sand aside to dry. • Test the water for conductivity. If it conducts electricity, then salt passed through the filter. • Boil off the water and retrieve the salt crystals. • You now have gravel, sand, and salt separated from each other. • Go to next slide.
Pure Substance? • Is sand a pure substance? • Is gravel a pure substance? • Is salt a pure substance?
Pure Substance or Mixture? • Air • Beach sand • Italian salad dressing • Ocean water • Salt • Sugar • Distilled water • Soda • Cupcake batter
Air Beach sand Italian salad dressing Ocean water Salt Sugar Distilled water Soda Cupcake batter Mixture Mixture Mixture Mixture Pure substance Pure substance Pure substance Mixture mixture Answers