Topic Test – Topic Review Activity – Flashcards
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Which of the following is not used to perform experiments with liquids? a. beakers b. flasks c. graduated cylinders d. rulers
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D
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_______ produces measurements that are close to one another. a. Accuracy b. Precision c. Estimation d. Rounding
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B
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Safety equipment like fire extinguishers and fire blankets are used to prevent accidents.
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False
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A transmission electron microscope would be the best microscope choice to study _______. a. structures smaller than cells b. single celled organisms c. plant leaves d. amphibian organs
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A
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Following proper safety guidelines _______. a. minimizes the chance of accidents occurring in lab b. involves using a fire extinguisher c. prevents accidents from occurring in lab d. requires using a safety shower
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A
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Explain why the several different types of microscopes are all necessary.
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The different types of microscopes are all necessary because not all experiments require the same level of magnification. For dissections low magnification is sufficient, so a dissecting microscope works very well, while for viewing single cells the 1000 fold magnification of a compound light microscope is more than adequate.
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Use an example to explain how the available tools can affect the precision of a measurement.
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Possible answer: A clock with a second hand is adequate for measuring a pulse rate or boiling an egg; however, a device that can record time in hundredths of a second is required for track meets.
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An experiment looking at structures smaller than a cell would most likely employ a _______. a. dissecting microscope b. transmission electron microscope c. scanning electron microscope d. compound light microscope
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B
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Suppose you read the following description in the want ads for a used car: mint condition, 55,000 miles on the odometer, model XJ4500, willing to accept reasonable offer. Describe the usefulness of each piece of data. What do the more valuable pieces of data have in common?
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Mint condition and reasonable offer aren't very helpful because they depend on the interpretation of the user. The mileage and the model are more useful because they supply specific numerical information about wear and features.
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Describe how the meniscus is used to read volume measurements on a graduated cylinder.
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The liquid in a graduated cylinder curves up at the edge where the liquid meets the wall of the cylinder. This curve in the liquid is called the meniscus and is used to determine the volume of liquid in a graduated cylinder by observing the measurement tick closest to the bottom of the meniscus.
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What are the two rules for deciding the number of significant digits in the answer to a calculation?
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(1) For multiplication and division, you determine the number of significant digits in each number in your problem. The significant digits of your answer is determined by the number with fewer digits. (2) For addition and subtraction, you determine the place value of each number in your problem. The significant digits of the answer is determined by the number that is least precise.
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What feature is common to all microscopes, and how is this feature related in the word microscope?
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All microscopes allow visualization of samples that are too small to be viewed by the naked eye. Microscopes let scientists make observations of microscopic objects. Microscopic objects are too small to be seen with the naked eye.
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Why is it important for a researcher to know all safety procedures and where all safety equipment is stored even if they never have an accident?
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Even a researcher who is perfectly safe is at risk from accidents caused by other people in the lab. If a lab partner spills chemicals that splash around, they might not be the only one in danger. Therefore it is important for all people working in a lab to know how to respond in emergency situations.
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Give an example of a situation when it would be appropriate to round a number and a situation in which it would not be appropriate to round a number. Explain the difference in the situations.
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A number might be rounded when determining the number of people who will attend a basketball game. A number should not be rounded when determining the number of students who will participate in a chemistry lab. Only an estimate is needed for attendance at a basketball game because everyone will still get to see the game. In a chemistry lab the correct number of students should be known so that everybody has the proper equipment to use.
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Explain the relationship between precision and accuracy.
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Accuracy describes how close a measurement is to the true value. Precision describes the ability to get similar answers when the same thing is measured several times.
