• Powders & Crystals


    Unit 2 Powders and Crystals

    Our second unit is a chemistry unit where we will learn about properties, powders, crystals, acids, bases, mixtures, solutions, and chemical reactions. 

     A powder is a substance that has been ground or pulverized into finely dispersed, loose, and solid particles.

    A crystal is the solid form of a substance in which the atoms are arranged in repeating patterns.

    Additional Vocabulary to Know

    Acid

    A substance with a pH less than 7 (the lower the number, the stronger the acid).  Has a sour taste and is capable of reacting with a base.

    Acidic

    Having the properties of an acid

    Base

    A substance with a pH higher than 7 (the higher the number, the stronger the base).  Is bitter to taste, slippery to the touch, and capable of reacting with an acid.

    Basic

    Having the properties of a base.

    Chemical analysis

    The process of determining the chemical makeup of a substance by observing its response to a series of tests.

    Chemical Reaction

    Two substances react to each other in a way that produces a change in each of them.

    Compound

    Made of 2 or more parts, elements, or ingredients.

    Crystal

    A solid form of a substance in which the atoms are arranged in repeating patterns.

    Dissolve

    When something is mixed into a liquid in an evenly distributed way, and is usually no longer visible as a separate substance.

    Gas

    Has neither a definite volume or a definite shape. It takes on the volume and shape of its container.

    Indicator

    A substance that shows – by change of color – that another particular substance is either present or absent.

    Insoluble

    Can’t be dissolved.

    Liquid

    Has a definite volume, but no definite shape.  Takes on the shape of the container that holds it.

    Melt

    A substance changes from a solid to a liquid state.

    Mixture

    A combination of 2 or more substances that are not changed chemically by being combined and can be easily separated.

    Neutral

    A substance that is neither acidic or basic; has a pH of 7.

    Particle

    A tiny piece of something.

    pH

    The scale on which scientists measure how acidic or basic a substance is.

    Powder

    A substance that has been ground or pulverized into finely dispersed, loose, solid particles.

    Prediction

    An educated guess of something that will happen.

    Property

    An observable characteristic or trait, such as color, shape, size, texture, smell, sound, etc.

    Senses

    How we receive information from the world through sight, touch, taste, smell, and sound.

    Solid

    Has a definite shape and volume.  Its shape and size can be measured.

    Solution

    Mixture in which one substance is dissolved in another.

    It is important to remember that mixtures start in pieces.  Then you combine these pieces together.  You can pull the pieces of a mixture apart again and will end up with the same molecules (in the same amount) you started with.

    To practice separating mixtures in an interactive.

    Solutions are groups of molecules that are mixed up in a completely even distribution.  For example, when you combine sugar and water, sugar dissolves and is spread throughout the glass of water.  The sugar is the solute (substance to be dissolved) and the water is the solvent (the one doing the dissolving).

    pH Scale

    The pH scale runs from pH 0 to pH 14.  Neutral solutions are exactly 7.  Acidic solutions have pH values less than 7.  Alkaline solutions have pH values of more than 7. 

    Chemical Reactions

    A chemical reaction is a change that produces one or more new substances from some starting materials.  Examples are iron rust, burning candle, fireworks, etc.