science chapter 11

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science chapter 11
2014-05-19 17:16:18
science chapter 11

science chapter 11
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  1. What are elements?  How many are there?
    they are the basic building blocks of matter - they combine to make up all kinds of matter - there are over 100 kinds of elements
  2. Each element has its own ___________ and _______________ properties that help identify the element.
    physical and chemical
  3. What do chemical properties of an element describe?
    how a material changes into other materials
  4. What are physical properties of an element?
    things that can be measured without changing the material - mass, volume, color, odor, and phase at room temperature
  5. How are physical properties identified?
    Observed, described, and measured with rulers, microscopes, thermometers, scales, and balances
  6. More than ________ of the elements are called metals.  What are the rest?

    some are gases
  7. What are the physical properties of metals?
    shiny, bendable, and able to conduct heat energy and electricity well
  8. Are things around us usually made of pure elements or combinations of elements?

    Example - rust = iron and oxygen
  9. Only a few elements (such as __________) are found in nature in pure form.
  10. What is weight?  How do you measure it?
    The measure of the pull of gravity on an object - measured with spring scales
  11. Is gravity the same everywhere on earth?
    No - it decreases at the top of a mountain - an object's weight on top of a mountain is a little less
  12. What is mass?  What does mass affect?
    the amount of matter in an object - mass affects the weight of an object
  13. Does an objects mass change based on gravity?
    No - mass stays the same
  14. How is mass measured?
    With a balance (grams, kilograms, milligrams) - the object is placed on one side of the balance while an object with a known mass is place on the other side
  15. What is volume? What is the calculation?
    The amount of space that an object takes up 

    L x W x H = volume (cubic units)
  16. What can you use to determine the volume of an object?
    graduated cylinder - put a measured amount of water in the cylinder then put the object in - read the new volume - the difference between the two volumes is the volume of the object
  17. Do a material's properties change?
    NO - no matter how you bend, cut, or crush it - the material's matter doesn't change
  18. What is the difference between object properties and material properties?
    Object properties change - volume, mass, weight, shape, size

    Material properties don't change - density, magnetism, color, hardness, texture
  19. What is density?
    a measure of the amount of matter in a given volume - a physical property of a material
  20. What is the calculation for density?
    mass divided by volume
  21. Does the density of a material change based on it's size?
  22. What is buoyancy?
    the ability of an object to float - if an object floats, it is buoyant
  23. What determines an objects buoyancy?
    the density of both the object and the liquid
  24. If the object's density is __________ than the liquid's density, it will float.
  25. If the object's density is __________ than the liquid's density, it will sink.
  26. Is ocean water more or less dense than fresh water? Why?

    because it has salt in it
  27. What is an atom?
    the smallest particle of an element that still has the properties of the element
  28. Are atoms different for different elements?
  29. Are atoms too small to be seen (even with a microscope)?
  30. The properties of atoms determine the properties of an element - TRUE OR FALSE
  31. What is the center of an atom called?
  32. What are found in the nucleus of an atom?
    neutrons and protons
  33. What is a neutron?
    has no electrical charge
  34. What is proton?
    has a positive charge
  35. An atom is identified by the number of _____________ it has.
  36. What are electrons?
    they move around the protons and neutrons and have a negative charge - they can join or leave atoms, or be shared between atoms
  37. Elements are organized in a table called the ____________________.
    Periodic Table of Elements
  38. Describe the rows and columns of the periodic table of elements.
    elements are arranged in the rows according to # of protons

    elements are arranged in columns according to chemical properties
  39. What are molecules?
    When atoms combine with other atoms
  40. Do atoms sometimes share electrons in some molecules?
  41. Many substances are found in nature as molecules, not as single atoms.  TRUE OR FALSE
  42. What is a compound?
    a type of matter made of a combination of elements
  43. Are properties of compounds different from the properties of elements that make them up?

    Example - water is a liquid at room temperature, but the elements (hydrogen and oxygen) that make up water are invisible gases
  44. What is a chemical formula?
    shows how many atoms of each element are in a compound


    Water is H2O - has 2 hydrogen atoms and 1 oxygen atom
  45. What is the formula for carbon dioxide?
  46. What does carbon dioxide form at really cold temperatures?
    dry ice - carbon dioxide can also be used to put out fires
  47. What forms salts?
    compounds in which particles are held together by opposite charges
  48. What do all salts have in common?
    have at least one kind of metal element and one kind of non-metal element

    they can form cystals
  49. Describe the elements that make up table salt
    sodium (can cause an explosion alone in water) and chlorine (is a poisonous gas) - together though they form a brittle white solid (salt) that we can eat
  50. MATTER is composed of ATOMS, which are bonded together to make MOLECULES. ELEMENTS are composed of only one kind of ATOM. ATOMS of different elements are bonded together to form COMPOUNDS. If ATOMS are aligned in perfect 3-dimensional arrangement, they form CRYSTALS.
  51. What determines whether a material is a solid, liquid, or gas?
    the arrangement and motion of its atoms or molecules
  52. What are the 3 phases or states of matter?
    Liquid, gas, or solid
  53. Describe a solid
    • definite shape and volume
    • particles vibrate in place and are very close together
  54. As a solid warms up it becomes a liquid - describe liquid
    forces hold the particles together but they can move about

    they do not have their own shape

    definite volume
  55. What is the freezing point or melting point?
    the temperature at which a liquid freezes or melts
  56. Is the freezing point different for different materials? Give an example
    Yes - salt water has a lower freezing point than fresh water
  57. Materials change size when their temperatures change.  TRUE OR FALSE
  58. The hotter the material the more the particles move about and have more space between them so that is why the material gets bigger.  TRUE OR FALSE
  59. What are the properties of gases?
    • does not have a definite shape or volume
    • particles are far apart
    • gases can be squeezed
  60. When does evaporation occur?
    when particles go from liquid to gas - higher temperature
  61. When does condensation occur?
    when a gas turns into a liquid
  62. Even when something is frozen, do the particles stop moving/vibrating?
    NO - they still vibrate
  63. So when something goes from a gas to liquid to solid - what changes in the spacing of the particles?
    The particle spacing is wider in a gas and gets smaller in a liquid and even smaller in a solid
  64. What is a mixture?  Give an example.
    different materials placed together but do not bond to form compounds - they can usually be separated again

    Example - salt and pepper mixed together - they can be separated again by placing the salt and pepper mixture in water - the pepper will float then you can heat the salt water to get the salt
  65. Many metals are mixtures called _____________.
  66. What is a solution? Give an example
    A special mixture where substances are spread out equally and will not settle

  67. In a solution, the substance that dissolves is called the _______________
    Solute (sugar)
  68. The ____________ is the substance in which the solute is being dissolved.
    Solvent (water = universal solvent)
  69. What two things will help a solute dissolve faster in a solvent?
    stirring or heating
  70. Not all solutions are made by dissolving a solid in a liquid.   TRUE OR FALSE
  71. What are 3 ways to describe a solution?
    • saturated - has the most solute allowed without changing the temperature
    • concentrated - has a medium amount of solute - close to being saturated
    • dilute - has least amount of solute
  72. Will salt dissolve in oil?
  73. What causes a solid to melt to a liquid and then a gas