Question | Answer |
Why did it take so long for scientists to prove that matter was made of atoms? | Scientists couldn't see them, so they had to come up (slowly) with experiments that showed how atoms were designed.
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| | What part of the atom did each of the following discover?2 | Thompson - electron, Rutherford - nucleus, Chadwick - neutrons2
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| | Why doesn’t matter usually exist in the plasma state on Earth?3 | Not hot enough3
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| | Why do atoms of liquids allow them to flow?4 | Because the molecules that the atoms make up can move past each other; they are not in a rigid configuration4
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| | What is sublimation?5 | The process by which a solid turns directly into a gas (skipping the liquid state).5
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| | List five physical properties of a pencil.6 | Six-sided, a graphite center, yellow color, wooden, rubber eraser, marks on paper, lightweight, etc.6
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| | What are two chemical properties of iron?7 | Iron combines with oxygen to form iron oxide (rust) and has extra electrons left over when it forms a metallic bond.7
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| | Suppose a geologist finds a mineral that is unknown to him or her. Which type of property would he probably use first to identify the sample? Explain.8 | Physical properties, because they are visible.8
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| | Describe three physical changes you could do to a piece of chalk.9 | Break it, dissolve it with vinegar, dip it in red paint, rub it so that it is square and not cylindrical.9
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| | Is dissolving a teaspoon of salt in a glass of water a physical or chemical change? Explain.10 | Physical. What happened to the salt is that it dissolved, but it did not cease to be salt.10
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| | Explain why a burning piece of paper quits burning.11 | There are no more materails to combine with oxygen and burn.11 |