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8th grade Compound and Mixtures intro to light

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  • Which method separates substances by boiling points?
    Magnetic separation
    Filtration
    Distillation
  • Iron filings can be separated from sulfur using a magnet.
    False
    True
  • An element cannot be:
    Heated
    Broken down by ordinary means
    Seen under a microscope
  • Which of these is an example of a homogeneous mixture?
    Salad
    Salt dissolved in water
    Oil and water
  • What’s the main difference between an element and a compound?
    Compounds have no mass
    Compounds are natural
    Elements contain one atom type, compounds contain two or more
    elements are not
  • What property of elements is used to identify them with an XRF spectrometer?
    Color
    Atomic structure and energy levels
    Texture
  • X-ray fluorescence helps scientists:
    Measure radiation
    Detect hidden objects
    Identify elements in materials
  • Which part of a chemical equation shows the new substances formed?
    Elements
    Products
    Reactants
  • A mixture of sand and water can be separated using:
    Chromatography
    Filtration
    Distillation
  • An element is a pure substance made up of atoms of the same kind.
    False
    True
  • In the reaction: Magnesium + Oxygen → Magnesium oxide, what is the product?
    Magnesium
    Carbon dioxide
    Magnesium oxide
  • What makes a compound different from its original elements?
    It weighs less
    It cannot be separated
    It has new, unique properties
  • Which of these is an example of a physical change?
    Burning paper
    Dissolving salt in water
    Cooking an egg
  • Which of the following is not a pure substance?
    Water
    Saltwater
    Iron
  • An XRF spectrometer is primarily used to:
    Identify elements in rocks and soil
    Measure temperature
    Detect radioactivity
  • A particle diagram would typically show:
    How atoms rearrange during reactions
    The weight of elements
    The temperature of a reaction
  • When iron and sulfur combine, they form:
    A gas
    Iron sulfide
    A mixture
  • A particle diagram of a compound shows:
    Random symbols
    Different atoms chemically bonded
    Identical atoms not touching
  • Which of the following best describes an element?
    A pure substance made of atoms of the same kind
    A compound with multiple properties
    A substance that can be broken down easily
  • What happens when magnesium burns in oxygen?
    The oxygen is destroyed
    It creates a new compound with different properties
    Nothing changes
  • Which statement about elements is TRUE?
    Elements are the simplest form of matter
    Elements always exist as liquids
    Elements can be easily broken down
  • Solute particles in a solution are too small to block light, making the solution transparent.
    True
    False
  • The term "reactants" in a chemical equation refers to:
    The final products
    The starting materials
    The laboratory equipment
  • The process of elements combining chemically is called:
    Mixing
    Compound formation
    Evaporation
  • IR spectrometers detect how compounds absorb infrared light to identify them.
    False
    True
  • In the word equation "Iron + Sulfur → Iron sulfide", what are the reactants?
    Iron and sulfur
    Iron sulfide
    Oxygen
  • What is a compound?
    A single type of atom
    A pure substance formed from two or more elements chemically bonded
    A physical blend of substances
  • What happens during a chemical reaction?
    Atoms disappear
    The mixture turns into a gas
    A new substance is formed
  • Evaporation and crystallization are methods to separate salt from salt water.
    True
    False
  • A chemical reaction involves:
    Rearrangement of atoms
    No change in atomic structure
    Complete destruction of matter
  • When scientists use an XRF spectrometer on a rock, they are primarily trying to:
    Determine its color
    Measure its weight
    Identify which elements are present
  • Simple distillation separates substances based on differences in boiling points.
    True
    False
  • A solution is a type of mixture, not a compound.
    False
    True
  • A compound has different properties than the elements that form it.
    False
    True
  • What does IR in IR spectrometer stand for?
    Intense Radiation
    Ionic Reflection
    Infrared
  • Which one of these is not a method used to separate mixtures?
    Filtration
    Evaporation
    Burning
  • What type of change occurs when iron rusts?
    Chemical change
    Physical change
    Dissolution
  • What is a solute?
    The liquid that dissolves a solid
    The leftover mixture
    The substance being dissolved
  • XRF spectrometers detect elements, not compound vibrations (that’s IR spectrometers).
    False
    True
  • An IR spectrometer helps scientists by:
    Measuring temperature
    Analyzing chemical bond vibrations
    Predicting weather patterns
  • Scientists use IR spectrometers to:
    Weigh substances
    Measure sound waves
    Detect chemical "signatures"
  • When magnesium burns in oxygen, it demonstrates:
    A cooling process
    A chemical reaction
    A physical change
  • Which tool is best for identifying the elements in a rock?
    Thermometer
    Microscope
    XRF spectrometer
  • Which statement is true about mixtures?
    They are always made of compounds
    They can’t be separated
    The components retain their original properties
  • A compound differs from an element because:
    It is formed by chemically combining different elements
    It exists only in laboratories
    It cannot be seen
  • What makes each element unique?
    Its color
    Its atomic structure
    Its temperature
  • A student mixes iron and sulfur and notices they can be separated with a magnet. What does this tell us?
    Iron turned into sulfur
    It’s still a mixture
    They formed a compound
  • In a mixture of iron and sulfur, the substances are not chemically bonded.
    True
    False
  • What kind of change occurs when water evaporates?
    Chemical reaction
    Physical change
    Nuclear reaction
  • Which of the following is a SOLID element at room temperature?
    Iron
    Oxygen
    Hydrogen
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