Substances and MixturesVocabulary Quizlet: https://quizlet.com/141124811/substances-mixtures-flash-cards/?new
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Substances & Mixtures
A pure substance is made up of only one kind of material. A mixture is made up of two or more materials mixed together.
Pure Substance
A pure substance is made up of only one kind of material. Pure water is a substance because it is only made up of water. Other examples of substances are silver, iron filings, ice, sugar, and salt. All of these are made up of only one kind of particle or material.
Mixture
A mixture is made by mixing two or more different materials together. For example, if a cup of salt and a cup of pepper are shaken up and mixed together, they form a mixture. The mixture has both salt and pepper. The salt and pepper can be separated from each other. Once they are separated, they will be just the same as they were before being mixed together.
Other examples of mixtures are milkshakes and salads. Mixtures can be made by combining solids, liquids, gases, or a combination of these.
After the parts are mixed, the mixture can be a solid, liquid, gas or a combination of different states of matter. Many mixtures can be found in nature. The saltwater in the ocean is a mixture of solids and a liquid. The atmosphere is a mixture of different gases.
The layers of the Earth are made of mixtures of rocks, and many rocks are mixtures of different minerals.
Making and Separating Mixtures
Making or separating a mixture is a physical change. For example, a chocolate shake is made by mixing chocolate ice cream with milk. The ice cream and the milk keep their identities- and flavors- even when mixed together. Some mixtures will mix faster when the temperature increases.
Separating a mixture is also a physical change. Saltwater is a mixture of salt and water. Saltwater can be separated into its two parts by evaporation, which removes the water and leaves the salt behind. The salt goes from being mixed with water to being separate, but it is still salt.
Mixture SeparationA mixture is made up of two or more substances that are not chemically combined. In a mixture, the substances keep at least some of their own properties. Mixtures can be separated by physical means.
The components or parts of mixtures and solutions can be separated from one another based on differences in the physical properties of those components. The properties of the substances determine how they can be separated. Solids may be separated based on their particle size, shape, color, or magnetic attraction. Some of the most common ways of separating mixtures of solids based on these properties include sorting, sifting, and magnetism.
Sorting
Sorting is a process in which two kinds of materials are hand-separated based on physical properties such as color. This process would be useful for separating larger pieces of things from one another. For example, sorting could be used to separate these different-colored jelly beans from one another or to pick pieces of fruit or vegetables out of a salad.
Sifting
Sifting is a method of filtering solids from one another based on particle size. Sifting can be used to remove small pebbles and shells from sand. A sieve or sifter like the one shown above is often used in kitchens to remove lumps from flour.
Magnetism
Mixtures containing two or more kinds of solids made of small particles can be separated most easily by using the physical property of magnetism if one (and only one) of the substances in a mixture is magnetic. An example of this kind of mixture would be sand and iron filings.
In the picture above, a magnet is shown attracting iron filings. If the filings were mixed with sand, the magnet would attract the filings, but not the sand.
SolutionsA solution is a type of mixture which is mixed together so well that the individual parts, or components, of the mixture can no longer be seen. In a solution, one substance is dissolved in another.
Sugar in water is an example of a solution. Sugar looks like tiny grains of white solid. But when the sugar dissolves in water (a clear liquid), the sugar takes on different properties so that the solid sugar can no longer be seen. The sugar-water mixture looks just like plain water.
Every sample of a solution has all its parts evenly mixed together. That is why every sip of lemonade tastes the same. Lemonade is a solution of water, sugar, and lemon juice mixed together.
Making a SolutionMaking a solution usually involves dissolving one substance, such as sugar, into another substance, such as water. If a substance is able to dissolve in water it is soluble. Some substances, such as sugar and salt, are soluble in water. Other substances, such as oil and plastic, are not soluble. There are factors that affect how well a soluble substance will dissolve. How fast a substance dissolves depends on the temperature, the size of the particles, and whether the solution is stirred or agitated.
- Temperature
Higher temperatures help solids dissolve in water faster. - Particle Size
Smaller particles of a solid are able to dissolve faster. For example, powdered sugar will dissolve faster than large grains of sugar or large pieces of rock candy. - Mixing/Agitation
Mixing or stirring the liquid once the solid has been added helps the solid to dissolve faster. This is why you stir a powdered drink into the water. - Surface Area – If more of the substance is exposed to the water it will dissolve more quickly. This is why flake cereal gets soggy faster than chunky granola cereal