the safest way to dilute concentrated sulfuric acid is to add ___ a. a series of small volumes of...

The safest way to dilute concentrated sulfuric acid is to add ___

A. a series of small volumes of water to the acid while stirring

B. the acid to water slowly while stirring constantly

C. the acid to a small volume of water and then add more water

D. dilute sulfuric acid to a small volume of the concentrated acid

1A Bio 11-03

The safest way to dilute concentrated sulfuric acid is to add ___

A. a series of small volumes of water to the acid while stirring

B. the acid to water slowly while stirring constantly

C. the acid to a small volume of water and then add more water

D. dilute sulfuric acid to a small volume of the concentrated acid

28 February

• Add acid to water

2. Scientific ProcessesBiology and Integrated Physics and

Chemistry• The student uses scientific methods during field and

laboratory investigations. The student is expected to:

A) Plan and implement investigative procedures including asking questions, formulating testable hypothesis, and selecting equipment and technology;

B) Collect data and take measurements with precision;C) organize, analyze, evaluate, make inferences, and

predict trends from data; andD) Communicate valid conclusions.

2A BioA

The table shows times required for water to evaporate from identical containers. Which of these is the best question to ask before developing a reasonable hypothesis to explain the data?

A Why does a lower temperature slow the rate of evaporation?B What is the boiling point of the water after both samples are heated?C Why does water exist as a solid at -15oC and as a liquid at 25oC?D How does the rate of evaporation change when a different container is used?

Time Required for Water Evaporation

Container A B

Volume of Water

(mL)25 25

Temperature (oC)

-15 25

Time Required

(h)72 24

2 March

• Temp/evaporation: read the data fields

2A BioB

Which question is valid in testing this hypothesis?

A Do most other scientists agree with the hypothesis?B Could abiotic processes account for the carbon dioxide?C What is the percent of argon compared to carbon dioxide in the Martian atmosphere?D Have the scientist’s other predictions about Mars been

validated?

A scientist has hypothesized that the existence of life on Mars is likely because Mar’s atmosphere is 95% carbon dioxide.

3 March

• How else could Mars get CO2?

2A BioD 11/06

Which of the following is the most likely hypothesis for the experiment described above?

A Vegetation that grows near roadways requires more water than vegetation in other areas.

B De-icing solution causes roadways to have more space for vegetation.C Vegetation near roadways changes the effectiveness of de-icing

solution.D De-icing solution affects some types of vegetation that grows near roadways.

A De-Icing Experiment

Some species of plants that commonly grow near roadways are used in an experiment. The plant species are divided into control groups and experimental groups. All groups are grown under identical conditions except that the experimental groups are given daily applications of a de-icing solution that is used on roadways in winter. At the end of one month, the growth of the control group and experimental groups is compared.

2A BioD 11/06

Which of the following is the most likely hypothesis for the experiment described above?

A Vegetation that grows near roadways requires more water than vegetation in other areas.

B De-icing solution causes roadways to have more space for vegetation.C Vegetation near roadways changes the effectiveness of de-icing

solution.D De-icing solution affects some types of vegetation that grows

near roadways. (4 March)

A De-Icing Experiment

Some species of plants that commonly grow near roadways are used in an experiment. The plant species are divided into control groups and experimental groups. All groups are grown under identical conditions except that the experimental groups are given daily applications of a de-icing solution that is used on roadways in winter. At the end of one month, the growth of the control group and experimental groups is compared.

2A BioD

11/06

Beaker 1 Beaker 2 Beaker 3(10 cm from light) (50 cm from light) (90 cm from light)

The picture shows an experiment designed to investigate biochemical activity in a water plant in a dark room. Over time, bubbles can be easily observed and counted as they escape the funnel. The number of bubbles is an indicator of the rate of photosynthesis. Which of these data tables best reflects that expected results of this experiment?

Beakers Number of Bubbles/Minute

1 0

2 15

3 20

A


1 10

2 0

3 20


1 15

2 15

3 15


1 20

2 10

3 0

B

C

D

21 March

• Plant closest to light has fastest photosynthesis.

2A BioB 10-04

In experiments, a benefit of larger sample sizes would be more ---

A. variables

B. representative data

C. time per group

D. control groups

22 March

• Larger sample = more representative data

2A BIOC 10-04

An engineer has created a new engine for race cars. It is necessary to know which fuel mixture will allow the engine to run at its peak performance. Which experimental design is best for this investigation?

A. Use one fuel mixture on the engine and measure its performance

B. Use one fuel mixture on many types of engines and measure their performance

C. Use various fuel mixtures on the engine and measure its performance

D. Use various fuels on many types of engines and measure their performance

2A BIOC 10-04

An engineer has created a new engine for race cars. It is necessary to know which fuel mixture will allow the engine to run at its peak performance. Which experimental design is best for this investigation? 23 MarchA. Use one fuel mixture on the engine and

measure its performanceB. Use one fuel mixture on many types of engines

and measure their performanceC. Use various fuel mixtures on the engine and

measure its performance (Test various fuel mixtures on engine)

D. Use various fuels on many types of engines and measure their performance

2A Bio

B 10-03The following boxes represent a field. Which pattern for collecting 10 samples would provide the best data for identifying the types of plants in a field?

X X X X X

A

X X X X X

X X X XB X X X X

X X

X X X

C X X X X X X X

X X X X X

D

X X X X X

24 March

• Random sampling = best data

2A BioH CTwo science students discovered that the mass of a

sample of acetone in an open beaker decreased within a few minutes. One student hypothesized that the acetone reacted with oxygen to form a gaseous compound that escaped. The other believed that the acetone evaporated into the air. What should the students do to test these hypotheses?

A. Combine the hypotheses so they give valid predictions of the acetone’s behavior

B. Conduct a study of original papers describing the experiments leading to acetone’s discovery

C. Perform an experiment that attempts to identify the gas above the open beaker

D. Ask a classmate’s opinion about the chemical and physical properties of acetone

2A BioH CTwo science students discovered that the mass of a

sample of acetone in an open beaker decreased within a few minutes. One student hypothesized that the acetone reacted with oxygen to form a gaseous compound that escaped. The other believed that the acetone evaporated into the air. What should the students do to test these hypotheses? 28 March

A. Combine the hypotheses so they give valid predictions of the acetone’s behavior

B. Conduct a study of original papers describing the experiments leading to acetone’s discovery

C. Perform an experiment that attempts to identify the gas above the open beaker

D. Ask a classmate’s opinion about the chemical and physical properties of acetone

2A BioA 11/05

Which study would most likely be used to investigate this hypothesis?

A Tracking dust clouds with satellite photos

B Determining the effects of iron on limestone

C Calculating erosion rates in African limestone mines

D Analyzing the content of comet dust clouds

The following hypothesis refers to iron in the topsoil on an island formed from limestone.

Hypothesis: Much of the iron found in the topsoil of the island was carried from Africa by huge dust clouds.

2A BioA 11/05

Which study would most likely be used to investigate this hypothesis? 29 March

A Tracking dust clouds with satellite photos

B Determining the effects of iron on limestone

C Calculating erosion rates in African limestone mines

D Analyzing the content of comet dust clouds

The following hypothesis refers to iron in the topsoil on an island formed from limestone.

Hypothesis: Much of the iron found in the topsoil of the island was carried from Africa by huge dust clouds.

2A BioD11/05

According to these data, which question was most likely by this activity?

A How warm do materials get when placed in an electric circuit?B Will an electric current change a metal into a nonmetal?C Which material requires the greatest voltage in an electric circuit?D Can an electric current be used to distinguish metals from other

materials?

Material Conducts

No

Electricity

Yes

Copper X

Glass X

Chalk X

Silver X

Wood X

Sulfur X

Tin X

Zinc X

Experimental Results

2A BioD11/05

According to these data, which question was most likely by this activity? (30 March)

A How warm do materials get when placed in an electric circuit?B Will an electric current change a metal into a nonmetal?C Which material requires the greatest voltage in an electric circuit?D Can an electric current be used to distinguish metals from other

materials?

Material Conducts

No

Electricity

Yes

Copper X

Glass X

Chalk X

Silver X

Wood X

Sulfur X

Tin X

Zinc X

Experimental Results

2A BioD 11/04

Which set of equipment would be best to use to test the effect of temperature on solution acidity?

A A balance and a thermometerB A pH meter and a barometerC A balance and litmus paperD A thermometer and a pH meter

1 April

• Temperature = thermometer; acidity = pH meter.

2A BioC11/04

A ruler placed between one student’s fingers and thumb is released without warning. A second student catches the ruler. The distance the ruler falls is recorded. This experiment is most likely designed to determine the ---

A effects of stress on the first student’s heart rateB acceleration of the ruler during its fallC second student’s reaction time to a stimulusD force applied on a falling mass

4 April

• Experiment tests 2nd student’s reaction time.

2A BioD 10/03Objects of the same mass but of different sizes

and shape were dropped from a given height. Their rates of free fall were measured and recorded. Which of the following is most likely the question this experiment was designed to answer?

A How does height affect the force of gravity?B How does gravity affect objects of different

densities?C How do mass and weight affect falling objects?D How do size and shape affect an object’s rate

of free fall?

2A BioD 10/03Objects of the same mass but of different sizes

and shape were dropped from a given height. Their rates of free fall were measured and recorded. Which of the following is most likely the question this experiment was designed to answer?

A How does height affect the force of gravity?B How does gravity affect objects of different

densities?C How do mass and weight affect falling objects?D How do size and shape affect an object’s rate

of free fall? (5 April)

2A BioB 10/04

Which lab setup would be appropriate to use in heating 100 mL of water to the boiling point?

A A 10 mL test tube held above a Bunsen burnerB A 200 mL beaker placed on a hot plateC A thermal coil inside a 100 mL cylinderD A sealed 300 mL flask in a warm-water bath

2A BioB 10/04

Which lab setup would be appropriate to use in heating 100 mL of water to the boiling point?

A A 10 mL test tube held above a Bunsen burnerB A 200 mL beaker placed on a hot plate (6 April)C A thermal coil inside a 100 mL cylinderD A sealed 300 mL flask in a warm-water bath

2A BioC 11/06A medical researcher hypothesizes that a newly

developed medication can reduce high blood pressure. Which of these would most likely be the dependent variable in a study involving this medication?

A The number of participants in the studyB The ages of people treated for high blood pressure with other medicationC The blood pressure of the participants in the

studyD The number of people treated for high blood

pressure with other medications

7 April

• Med study: blood pressure = dependent variable

2A BioC 11/06A medical researcher hypothesizes that a newly

developed medication can reduce high blood pressure. Which of these would most likely be the dependent variable in a study involving this medication?

A The number of participants in the studyB The ages of people treated for high blood pressure with other medicationC The blood pressure of the participants in the

studyD The number of people treated for high blood

pressure with other medications

2A BioD 11/06

Similar sprigs of elodea were placed in four test tubes. Each test tube contained water with a different concentration of salt ranging from 0 to 3 percent. The length of each sprig was measured after 10 days. Which of these questions can best be answered with this experimental setup?

A Can the amount of salt in the water help elodea avoid disease?B What happens to salt as elodea sues water?C Will elodea increase the amount of salt in the water?D Does the amount of salt in the water affect elodea growth?

2A BioD 11/06

Similar sprigs of elodea were placed in four test tubes. Each test tube contained water with a different concentration of salt ranging from 0 to 3 percent. The length of each sprig was measured after 10 days. Which of these questions can best be answered with this experimental setup?

A Can the amount of salt in the water help elodea avoid disease?B What happens to salt as elodea sues water?C Will elodea increase the amount of salt in the water?D Does the amount of salt in the water affect elodea growth? (11 April)

11 April

• How does salt affect elodea growth?

2A BioA 11/05

A valid study would include a control group containing ---

A bean seed, tomato seed, sunflower seed, an waterB water and 2% root hormoneC water onlyD bean seed, tomato seed, sunflower seed, water, and 1% root hormone

2A BioA 11/05

A valid study would include a control group containing ---

A bean seed, tomato seed, sunflower seed, and waterB water and 2% root hormoneC water onlyD bean seed, tomato seed, sunflower seed, water, and 1% root hormone

12 April

• Control contains all but one variable

2A BioA 11-04

Which of the following was probably the hypothesis for this experiment?

A The growth of bread mold increases as temperature increases.B The type of nutrient causes bread mold to grow faster at higher

temperatures.C The size of the plates determines the temperature of bread

mold.D The temperature of bread mold is determined by the mold’s

growth.

Students placed equal amounts of bread mold on 12 identical agar plates containing the same amounts and types of nutrients. Four plates were kept at 0oC, four were kept at 45oC, and four were kept at 22oC (room temperature). The plates were examined after five days.

13 April

• Warmer temp = faster mold growth

2A BioC 11-04

Moon Chemistry Samples collected by Apollo astronauts have provided new data about the moon. Some of these samples consisted of lunar soil, a fine-grained, sand-like material produced as a result of the destruction of moon rocks. Traces of beryllium-10 were found in the samples. Beryllium-10 is carried by the solar wind, which transports elements from the sun’s surface and deposits them on the moon. The solar wind may also result in the formation of new substances. Tiny teardrops of iron and specks of molybdenum were found inside the particles of lunar soil. This is interesting because these elements have not been found in an uncombined state on Earth. The metal oxides they originally were part of were possibly changed when bombarded by the positively charged particles of the solar wind. Another interesting find was tiny (1 to 3 micrometers in length) crystals of silver sulfide. Because similar particles are found on Earth, it has been hypothesized that these crystals were created at a time when the moon had a molten core.

Which procedure is best to use when determining the density of a rock?

A. Place the rock in a water-filled beaker and find the height at which the rock floats above water.

B. Use a ruler to measure the rock’s dimensions and then find its mass using an analytical balance.

C. Measure the mass of the rock on a balance and then find the volume of water it displaces in a graduated cylinder.

D. Place the rock in three liquids with different densities and observe which liquid the rock floats in.

14 April

• For rock density: mass on balance, volume from water displacement.

2A BioA 10/03

Which of these is a hypothesis that can be tested through experimentation?

A Bacterial growth increases exponentially as temperature increases.

B A fish’s ability to taste food is affected by the clarity of aquarium water.

C Tadpoles’ fear of carnivorous insect larvae increases as the tadpoles age.D The number of times a dog wags its tail indicates how content the dog is.

15 April

• Experiment can test bacterial growth/temperature.

2A BioB 11/06

A student is working with four beakers that each contain a clear liquid. Which set of procedures would be best to use to determine whether one of the beakers contains only distilled water?

2A BioB 11/06

A student is working with four beakers that each contain a clear liquid. Which set of procedures would be best to use to determine whether one of the beakers contains only distilled water? 18 April: H2O: odor, pH, density, boiling pt

2A BioB 11/05Only 10% of the electrical energy operating a

lightbulb is changed into visible light. Which instrument helps identify the energy change occurring to most of the remaining 90%?

A Triple-beam balanceB ThermometerC Magnifying glassD Prism

19 April

• Electricity to light energy… lose heat

the safest way to dilute concentrated sulfuric acid is to add ___ a. a series of small volumes of...

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