Nature of Science - OCHS Chemistry

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Practice Packet Unit 1: The Nature of Science Pre-AP Chemistry 1 Unit 1: Nature of Science Name: ___________________________ Class Period: ________ Nature of Science

Transcript of Nature of Science - OCHS Chemistry

Practice Packet Unit 1: The Nature of Science Pre-AP Chemistry

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Unit 1:

Nature of Science

Name: ___________________________

Class Period: ________

Nature of Science

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Vocabulary

For each word, provide a short but specific definition from YOUR OWN BRAIN! Don’t give a textbook or an internet definition. Write something that will help YOU remember the word.

Absolute Zero: _____________________________________________________________________________

Accuracy: _________________________________________________________________________________

Argument: ________________________________________________________________________________

Celsius: __________________________________________________________________________________

Density: __________________________________________________________________________________

Kelvin: ___________________________________________________________________________________

Meniscus: ________________________________________________________________________________

Mass: ____________________________________________________________________________________

Precision: _________________________________________________________________________________

Percent Error: _____________________________________________________________________________

Scientific Notation: ________________________________________________________________________

Significant Figures: ________________________________________________________________________

Volume: __________________________________________________________________________________

Water Displacement: _______________________________________________________________________

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Lab Safety

Draw a diagram of our science room and label the locations of the following:

ü Fire Extinguisher ü Fire Blanket ü Eyewash Stations (2) ü Emergency Shower ü Waste Disposal Containers (trash cans) ü Goggle Storage ü Emergency Shut Off (2) ü Vent Hood ü Emergency Exits (3)

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The Nature of Science Assessment

(Select True or False)

______ HYPOTHESES BECOME THEORIES OVER TIME THAT IN TURN BECOME LAWS

______ SCIENTIFIC LAWS ARE ABSOLUTE

______ A HYPOTHESIS IS AN EDUCATED GUESS

______ THE SCIENTIFIC METHOD IS A UNIVERSAL STEP BY STEP PROCEDURE THAT ALL

SCIENTISTS WHO CONDUCT RESEARCH FOLLOW

______ CAREFULLY COLLECTED EVIDENCE WILL RESULT IN SURE KNOWLEDGE

______ SCIENCE AND ITS METHODS PROVIDE ABSOLUTE

______ SCIENCE IS MORE PROCEDURAL THAN CREATIVE

______ SCIENCE AND ITS METHODS CAN ANSWER ALL QUESTIONS

______ SCIENTISTS ARE OBJECTIVE IN THEIR WORK

______ EXPERIMENTS ARE THE PRINCIPAL ROUTE TO SCIENTIFIC KNOWLEDGE

______ SCIENTIFIC CONCLUSIONS ARE REVIEWED FOR ACCURACY BY OTHER SCIENTISTS

______ ACCEPTANCE OF NEW SCIENTIFIC KNOWLEDGE IS STRAIGHTFORWARD

______ SCIENTIFIC MODELS REPRESENT REALITY

______ SCIENCE AND TECHNOLOGY ARE IDENTICAL

______ SCIENCE IS AN INDIVIDUAL PURSUIT

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Lab Equipment

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Scientific Argumentation

1. Why do scientists make arguments?

2. What are the 3 parts of a Scientific Argument?

3. What is a claim?

4. What is evidence?

5. What is reasoning?

6. Reasoning links the _______________________ (data) to the _________________________.

7. Is the data appropriate and sufficient to support the claim that Mr. Palermo is a good basketball player? Complete the chart below.

8. Do you think this is sufficient evidence to support the claim? Explain.

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Constructing a Scientific Argument

You perform an investigation to determine if ice floats in rubbing alcohol. First you make a prediction (what you think will happen based on prior knowledge/experiences).

I predict that ice will sink/float in alcohol.

Now determine how you will conduct your experiment. Once your group has decided how you will proceed you can start your investigation and collect your evidence. Record your data below.

Procedure:

Evidence:

Now that you have your evidence, make a claim regarding the initial question “does ice float or sink in rubbing alcohol?”

Claim:

Lastly, provide scientific reasoning as to why the ice floats or sinks in the alcohol. Just like a DBQ in social studies, this is where you justify why the claim is supported by the evidence using accepted scientific principles.

Reasoning:

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Graphing Skill: What Type of Graph is it? There are several types of graphs that scientists often use to display data. They include:

Pie Graphs Bar Graphs Histograms Line Graphs Scatter Plots

• Dependent variable is NOT continuous

• Usually presents data as a “part of a whole” or as percentages

· Dependent variable is NOT continuous · There is no order to the categories on the X-axis · Bars typically don’t touch · Y-axis is usually a percentage or a frequency (count)

· A specific type of bar graph · Dependent variable must have a natural order that can be grouped into defined “chunks” · Bars must always touch · Y-axis is usually a percentage or a frequency (count)

· Dependent variable IS continuous · Points are plotted using x- and y-components · The points are connected because the observations are NOT independent (the next value depends on the previous value)

· Dependent variable IS continuous · Points are plotted using x- and y-components · The points are NOT connected because the observations are independent (the next value does NOT depend on the previous value) · Uses a best-fit line or curve to show relationship

Based on these definitions, and the descriptions of the experiments below, please put an “X” in the box for the type of graph that would be most appropriate (some descriptions may have several graph types that would be appropriate; you only need to select one). # Description Pie Bar Histo. Line Scatter Ex A graph showing the number of 5th graders who prefer Coke or Pepsi X

1 A graph showing how a newborn baby’s weight changes over time

2 A graph showing the percentage of the class earning As, Bs, and Cs.

3 A graph showing the distribution of trees of different size groups (e.g. 0-10cm, 10-20cm, etc…) in a forest

4 A graph showing the relationship between height and arm length

5 A graph showing the percentage of an allowance spent on different categories (e.g. food, movies, etc)

6 A graph showing the amount of rainfall, by month over a 12 month period

7 A graph showing the number of ice cream cones purchased as a function of the day’s temperature

8 A graph showing the number of pushups done each day during a 2-week training program

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Graphing Skill: Labeling Axes

When labeling your axes, keep 3 things in mind: • The independent (manipulated) variable is written along the horizontal axis (X axis) • Dependent (responding) variable is written along the vertical axis (Y axis) • Units on any variables should be included in parentheses ( ) following the axis title

Graphing Skill: Creating Titles When writing a title for you graph, please remember: • Must communicate the dependent and independent variables • Can be presented in the form “Y versus X” • Some graphs need more explanation than others. Make sure your reader would be able to understand what your

data represent

Add Titles to Graph’s 1-4 above.

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Graphing Skill: Scaling Axes

There are a few important steps involved in correctly scaling an axis: • STEP 1: Find the range for the variable

• Range = Largest Value - Smallest Value • STEP 2: Divide the range by the number of intervals you want (not too many or too few). We don’t want all of

the data smooshed in only part of the graph; spread it out. • After dividing, we may need to round up to get a number that is easy to count by. (It is easier to count by

2s instead of 1.9s) • STEP 3: Use the rounded number to mark off intervals along the axis.

• The interval must be the same amount each time (count up by the same number).

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Metric

1. Complete the following number line by adding the prefixes that pertain to the marked values:

2. If a substance weighs 2.00 grams and you need the mass in kilograms, will the number appear to become smaller or larger? Explain your answer. 3. If a liquid has a volume of 5800 mL and you need the mass in Liters, will the number appear to become smaller or larger? Explain your answer. 4. Convert the following: Show your work!!

900 km = __________ m

568 mm = __________ m

200 kg = __________ g

52 mg = __________ g

5.00 m = __________ km

0.025 J = __________ mJ

7000 J = __________ kJ

0.859 s = __________ ms

800 cm= __________ m

0.0256 m = __________ µm

20 cg = __________ g

0.000589 g = __________ ng

2.0 L = __________ cL

5. How many Celsius degrees separate the freezing and boiling points of water? _______

What are these two temperatures? ________ & _________

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6. What is the lowest possible temperature in °C? _________ 7. How many Kelvin separate the freezing and boiling points of water? ______

What are these two temperatures? ________ & ________

8. What is the lowest possible temperature in Kelvin? __________ 9. Convert the following temperatures:

Test Practice Questions

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Precision versus Accuracy

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Significant Figures

Test Practice Questions

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Rounding with Significant Figures

If a piece of glassware is very precise it may have a lot of sig figs, as many as 4. A less accurate piece of glassware such as a beaker will only have 1 sig fig. If both pieces of glassware are used to measure quantities in a lab we have to round our results to the least precise measurement. When working with measurements the quantity with the least decimal places is the least precise. For example, if the beaker measures 10mL and a cylinder measures 10.1mL the cylinder is more precise. If the two quantities are added together the new volume is 20mL. The decimal must be rounded to make our answer to one sig fig. Therefore the rule is:

When performing calculations with our data sometimes we have to multiply and divide our data. In this case, the most precise answer is the one with the most sig figs. Since we need to round to our least precise measurement, we should round to the least number of sig figs given. For example, if the mass of a substance is 10.0 grams (3 sig figs) and the volume is 2 mL (1 sig fig) the density is 5 g/mL also (1 sig fig). The rule is:

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Scientific Notation

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Density

For each problem below, write the equation and show your work. Always use units and box in your final answer. 1. Generally, what phase of matter (solid, liquid or gas) has the lowest density? Highest?

2. Bubbles in soda (coke) rise to the surface. Explain this in terms of density.

3. The density of silver (Ag) is 10.5 g/cm3. Find the mass of Ag that occupies 965 cm3 of space.

4. A 2.75 kg sample of a substance occupies a volume of 250.0 cm3. Find its density in g/cm3.

5. Under certain conditions, oxygen gas (O2) has a density of 0.00134 g/mL. Find the volume occupied by 250.0 g of O2 under the same conditions.

6. Find the volume that 35.2 g of carbon tetrachloride (CCl4) will occupy if it has a density of 1.60 g/mL.

7. The density of ethanol is 0.789 g/mL at 20oC. Find the mass of a sample of ethanol that has a volume of 150.0 mL at this temperature.

8. A rectangular block of lead (Pb) measures 20.0 mm X 30.0 mm X 45.0 mm. If the density of Pb is 11.34 g/cm3, calculate the mass of the block.

9. An irregularly-shaped sample of aluminum (Al) is put on a balance and found to have a mass of 43.6 g. The student decides to use the water-displacement method to find the volume. The initial volume reading is 25.5 mL and, after the Al sample is added, the water level has risen to 41.7 mL. Find the density of the Al sample in g/cm3. (Remember: 1 mL = 1 cm3.)