Science mid term

Card Set Information

Science mid term
2011-12-19 22:58:36
science mid term suzanna arul

Science Mid-term question
Show Answers:

  1. What
    are the 6 metric prefixes?
    • Kilo, Hecto, Deka, Deci, Centi, Mili
    • (King Henery Died by drinking Chocolate Milk)
  2. Compare and Contrast accuracy and precision.
    Accuracy means getting a result that is close to the real answer. Precision means getting a similar result every time you try.
  3. Define
    • The
    • ability of a material to be drawn into wire.
  4. What makes John Dalton special?
    • Father
    • of atomic theory
  5. What forces are at work inside an atom?
    • gravitational force,
    • electromagnetic force, strong force, weak force
  6. What units do we use to measure volume ?
    • D = m/vSo g/ml for liquids and irregular solids
    • and g/cm3 for regular solids
  7. What is a controlled experiment?
    An experiment in which all of the variables are controlled by the experimenter.
  8. What does it mean if a substance is malleable?
    The ability of a substance be hammered into sheets.
  9. •What is Group 1 called?
    Alkali metals
  10. What are the common characteristics of the Alkali metal group?
    Low density, silver/white metal, very soft, highly reactive
  11. What is Group 2 called?
    Alkaline Earth Metals
  12. What are the common characteristics of Alkaline Earth metals?
    • Higher densities than alkali
    • metals, silver in color, very reactive but not as reactive as alkali metals
  13. •How many kiloliters are in 500 liters?
    0.5 kl
  14. An object has a density of 1.8 g/ml. Will the object sink or float?
    • Since water has a density of
    • 1g/ml than it will sink in water. If it
    • is in a substance like mercury that has a density of 13.5 g/ml, it would float
    • in mercury
  15. What happens to a helium balloon when it is taken
    outside on a cold winter day? Explain why.
    A balloon taken outside on a cold day would shrink in volume. The reason is because as the air in the balloon (helium) lowers its temperature to match the outdoor temp, the lower temperature causes the volume of the helium to decrease. The volume of a gas is directly proportional to its temperature.
  16. What happens to chemical bonds during a chemical reaction?
    • They are
    • broken and new ones are formed.
  17. Do the Noble Gases bond?
    • No, they have a full shell
    • of valence electrons which makes them unreactive.
  18. What tools do you need to calculate density?
    • A triple beam balance to measure mass, ruler (to measure length width and height of a regular solid, and a graduated cylinder to measure liquids and irregular solids
    • volume.
  19. What is concentration?
    The amount of solute compared to the amount of solution.
  20. Why would an ion carry a negative charge?
    It will be negative if it gains an electron.
  21. What is a precipitate?
    Forms as a solid during a chemical reaction of two liquids. It will fall to the bottom due to its higher density than the liquid it is in.
  22. The mass of an object is 25g and the volume is 5ml.
    What is the density?
    5 g/ml
  23. Compare mass and inertia
    Mass is what everything is made of. The more mass an object has, the more inertia it has. Inertia is the ability of an object to resist a change in motion.
  24. How can we change the rate of solubility?
    Raise the temperature, stir the solution, and or break the solute into smaller pieces.
  25. What are 3 signs of a chemical reaction?
    Production of a gas, heat, light, fizzing, bubbling, color change, fire, smoke, odor change
  26. Who’s theory about the atom was called “plum pudding?”
    JJ Thomson
  27. What does the term “periodic” mean?
    Happening at regular intervals
  28. Why are the Noble Gases “noble?”
    because they have full shell of valence electrons which makes them un-reactive
  29. Give an example of an element, a mixture, and a compound.
    Element – silver, iron, silicon, etcMixture – chocolate chip cookie, granite, kool-AidCompound – carbon dioxide, water, ammonia, salt, etc.
  30. Compare a solute to a solvent.
    A solute is dissolved in a solvent. There is usually more solvent than solute. The solute is a solid and the solvent is a liquid.
  31. What is Rutherford credited for?
    Discovering the positively charged, densely packed nucleus
  32. Who was the first scientist to organize the Periodic
    Table of Elements?
    Dmitri Mendeleev
  33. What is the purpose of a valence electron?
    It determines the reactivity of an element.
  34. Define an atom.
    The smallest particle of matter that still retains properties of a substance.
  35. Compare an atom, element, molecule, and a
    Atoms are the smallest particle of matter. Molecules are made of two or more atoms. All molecules are made up of the atoms of two or more elements.
  36. What unit do we use to measure atomic mass?
  37. What are the 6 metalloids?
    Boron, Silicon, Germanium, Arsenic, Antimony, Tellerium
  38. Give an example of a molecule.
    Water (H2O), or oxygen we breathe (O2), many more…
  39. What Greek Philosopher came up with the idea for an atom?
  40. What does the atomic number tell you?
    The number of protons and electrons.
  41. What charges do the subatomic particles hold?
    proton and neutron – inside the nucleus, electron – outside the nucleus
  42. What group is called the Halogens?
    Group 17
  43. What is the result of a chemical reaction?
    A new substance with new properties is formed. The identity of the original substance has been changed.
  44. What are the vertical columns called on the periodic table?
  45. What are the horizontal rows called on the periodic table?
  46. What is the formula for speed?
    Average speed = d/t
  47. What do we call continuous acceleration in a circle?
    Centripetal acceleration
  48. What do you have to overcome to lift an object?
  49. What does Newton’s First Law State? Give an
    An object in motion will stay in motion and an object at rest will stay at rest unless acted on by an unbalanced force.
  50. What 2 factors affect friction?
    roughness of the surface and the weight of the object
  51. •Calculate the speed: 50meters and 10seconds
    Average speed = d/tAv Sp = 50m/10 sAv sp = 5 m/s
  52. •Define force. What unit do we use to measure force?
    A force is a push or a pull on an object and it is measured in Newtons (N).
  53. •What is inertia?
    Inertia is the property of an object to resist a change in motion. The more mass an object has the more inertia
  54. •How do we represent gravity numerically?
    The gravity constant or the acceleration due to gravity of a falling object. On earth an object will fall at an acceleration of 9.8 m/s2. This means for each second an object falls, it will increase its velocity by 9.8 m/s.
  55. •What is velocity?
    Speed in a particular direction
  56. •What are the 2 kinds of friction?
    Static friction and kinetic friction.
  57. •Differentiate between weight and mass.
    The mass of an object is a measure of how much matter is in an object. This cannot change no matter where an object is (in the universe). Weight is a measure of gravity’s pull on an object. The weight of an object will be determined by the gravity of the moon/planet that an object is on. The mass of an object cannot change but the weight of an object can, depending on its location. This is why we have the same mass on earth and the moon but we weigh less on the moon.
  58. •How are mass and inertia related?
    The more mass something has the more inertia it has
  59. •Define acceleration.
    The change in velocity over time.
  60. •State one way that friction can be helpful and one way that friction can be harmful.
    Answers vary but helpful friction is explained as friction that works to make something do what we want it to do. Car tires need friction to stay on the road. This is helpful. Inside a car’s engine, friction is breaking the metal pistons down as they rub together creating excessive heat and mechanical break down of engine parts. This is harmful friction.
  61. •Where is the only place an object can be in a true free fall?
    Where there is no influence from air resistance, so technically, any place that has no air. The moon and space are examples.
  62. •What does Newton’s Third Law state?
    For every action there is an equal and opposite reaction. It also states that all forces act in pairs.
  63. •What are the 2 types of acceleration?
    Acceleration or positive acceleration and deceleration or negative acceleration.
  64. •What is gravity? What unit do we use to measure gravity?
    Gravity is a measure of the force between two objects that have mass. It is measured in Newtons.
  65. •What 2 movements/motions are involved in projectile motion?
    Vertical acceleration (imparted by gravity) and horizontal motion (given to object at the beginning of its journey).
  66. •Give an example of Newton’s 3rd Law.
    Answers vary but playing pool (billiards) is a good example of Newton’s 3rd Law. When one ball hits another ball, the ball being struck imparts and equal and opposite force to the ball doing the striking, thus allowing it to be “pushed away”.
  67. •What is the formula for calculating the change in velocity?
    V = d/t (in a particular direction)
  68. •Calculate the change in velocity: A penny falls from a stairwell and travels 7 seconds. What is it’s velocity as it hits the ground?
    V = gxtV = 9.8 m/s2 x 7sV = 68.6 m/s
  69. •How does air resistance affect gravity?
    It impedes the acceleration of an object as it falls. It essentially gets in the way and creates a force that works against gravity’s pull.
  70. •What is terminal velocity?
    The maximum velocity that is reached when an object accelerated due to gravity on earth. An object should never stop accelerating as it falls towards the earth but the air resistance eventually pushes back with enough force to keep the falling object from accelerating anymore. Objects that have an atmosphere will have a terminal velocity. Planets and moons with no atmosphere will not have a terminal velocity
  71. •Describe net force.
    The sum of all the forces acting on an object
  72. •What is Newton’s Second Law of Motion?
    Newton’s 2nd law of motion says that there is a relationship between the mass, acceleration, and force applied on an object. Or said another way, the acceleration of an object will depend on the force applied and how much mass it is.F=ma
  73. •What happens when forces are traveling in the same direction? In the opposite direction?
    • Forces traveling in the same
    • direction are added together to find the net force while forces traveling in
    • opposite directions are subtracted from on another.
  74. •What are the factors involved in Newton’s Second Law?
    Force, mass, and acceleration
  75. •Describe a balanced force. What can balanced forces NOT do?
    A balanced force is one in which no net forces result on an object. If there are no net forces then an object cannot change its current motion. If it is moving it will stay moving. If it is at rest it will stay that way unless it is acted on by an un-balanced force.
  76. •Define Work.
    The transfer of energy to an object by a force that results in the object moving in the direction of the force.
  77. •Give an example of Newton’s 2nd Law.
    Answers vary but, if you want to accelerate more as a runner, you can run harder (add more force) or lose mass (lose weight).
  78. •Describe an unbalanced force. What can unbalanced do?
    An unbalanced force is a force that is not cancelled out by an equal and opposite force. A positive net force is created which allows an object to change its motion.
  79. •What formula do we use to calculate work?
    W = F x d
  80. •What is the formula for acceleration?
    Acceleration = (final velocity-starting velocity)/ the time it takes to change velocityORAcc = (VF – VS)/ change in time
  81. •How is friction involved in unbalanced forces?
    Friction is an unbalanced force that creates change in the motion of an object.
  82. •What is the unit we use for work?
    Newton meters or joules.
  83. •Give an example of a wedge.
    Knife, plow, cleats (on sports shoes), etc.
  84. •Define Momentum.
    Momentum is dependant on the mass of an object and its velocity. An object that has a lot of momentum will be difficult to stop. In other words, the more mass and velocity an object has (momentum) the harder it is to stop. Would you rather try to stop a bike or a car? Generally a car will have much greater momentum because of the large mass difference. A bike would have to go ridiculously fast to have more momentum than a car. Certainly a person riding a bike would never be able to go fast enough to account for the smaller mass of a bike versus a car.
  85. •What is Power?
    Power is the rate at which work is done.
  86. •Give an example of a screw.
    A wood screw, cork screw (wine bottle opener), a jar lid
  87. •Give an example of a wheel and axle.
    Cars tires, door knob, etc.
  88. •Define energy
    The ability to do work.
  89. •Give an example of an inclined plane.
    Wheel chair ramp, stairs, etc.
  90. •What are the 2 kinds of mechanical energy?
    potential energy and kinetic energy
  91. •What is GPE? How do you calculate GPE?
    • gravitational potential energy
    • GPE = weight x height
  92. •What is energy conversion?
    Energy conversion is energy going from one form to another. For example, sunlight (light energy) travels to the Earth and hits a road (asphalt). The road becomes warm, or said another way the light energy converts into thermal energy (heat).
  93. •Is perpetual motion possible?
    Perpetual motion is not possible because some energy is “lost” due to the internal friction of the moving parts of any machine. We can try to reduce the friction in a machine but you can never remove all of it. Consequently, some mechanical energy is converted into thermal energy (heat) due to the friction of parts that are in contact with one another.
  94. •Differentiate between a theory to a law.
    A law tells us how things work. A law is more of a summary of data and observations.A theory explains how and why something happens. It is more of an explanation of the data and observations.
  95. •How does a chemical change differ from a chemical property?
    A chemical property tells us what a substance CAN DO while a chemical change is what a substance DOES DO. Also:A chemical property predicts how a substance will react while a chemical change tells us how a substance reacted.
  96. •What can change energy into different forms?
    A machine
  97. •What are the signs of a chemical change?
    Odor change, smoke, fire, color change, production of a gas, fizzing, bubbling, heat, light, etc.
  98. •Which of the following is a chemical property? Malleability, Ductility, Conductivity, or Density
    None, these are all physical properties.
  99. •What tools are used for measuring mass (and weight)?
    • Mass: triple beam
    • balance

    • Weight: spring
    • scale
  100. •Give an example of a colloid and a suspension.
    • Colloid: mayonnaise, toothpaste, jello
    • Suspension: snow globe
    • *Note: A suspension can have solid particles large enough to be trapped in a filter while a colloid’s particles are too small to be captured by a filter.