Review TAKS for Science

Quick TAKS Doctor

Please note those questions you missed, and the correct answers.

1 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

• The safety rule says always add acid to water, so A & C are out since they both add water to acid.

• D doesn’t even make sense since you can’t make concentrated acid out of a dilute acid by adding to it.

• So the answer is

2. Which of the following plant adaptations is not suited for a desert environment?

A. Large, thin leaves

B. Shallow roots

C. Small, spiny leaves

D. Thick, fleshy stems

What key ideas do we need to understand?

Desert means dry and extreme temperature changes.

So, to survive we must gather lots of water when we can, and store it. We shouldn’t have large areas from which water can evaporate, so B, C and D would all be good things. Answer: A

3 Which of the following groups contains members with similar chemical reactivity?

A Li, Be, C

B Be, Mg, Sr

C Sc, Y, Zr

D C, N, O

Lets look at the Table provided.

• To have similar chemical properties of any kind, they must be in the same Group or Family.

• Groups are columns, so the answer would be

• B

4 Most viruses infect a specific kind of cell. Which of the following are infected by the human immunodeficiency virus (HIV)?

A Helper T cells

B Liver cells

C GABA-receptor cells

D Red blood cells

Ask yourself, which cell type deals with immunity?

Answer? Helper T cells. All the rest are body cells with specific jobs that do not relate to immunity.

5. Many doctors recommend 800 µg of folate, 400 µg of vitamin B12, and 50 mg of vitamin B6 per day to improve cardiovascular health. Based on this information and the nutrition label, the cardiovascular health benefit of a 1-ounce serving of this cereal is:

A doubtful because it provides insufficient folate and vitamin B6 and lacks vitamin B12

B superb because it contains only 22 g of carbohydrates and 75 mg of sodium

C excellent because it provides all needed vitamins and is low in fat and cholesterol

D poor because it raises blood cholesterol levels with its high fat and cholesterol content

Since the question asks about the nutritional value based on Folate and the B vitamins, evaluate the answers based on the same information.

B is not valid since no information is given as to what are good levels.

C is not valid as it does not provide all the vitamins.

D is not a valid answer since it is very low in fat.

ANSWER: A

6 This experiment probably was set up to determine —A how much

mechanical energy the battery produces

B the pH of water during electrolysis

C the pressure created by an electric current

D how much energy is converted to heat

To answer, look at what is being measured.

• A refers to mechanical energy, where?

• B refers to pH, and there is no pH meter.

• C refers to pressure, and there is no barometer.

• Since there is a thermometer to measure temperature change it must be D.

• A 0.2 N• B 0.8 N• C 1.5 N• D 6.0 N

7 The frog leaps from its resting position at the lake’s bank onto a lily pad. If the frog has a mass of 0.5 kg and the acceleration of the leap is 3 m/s2, what is the force the frog exerts on the lake’s bank when leaping?

Formula chart says F=ma, m is mass in kg, a is acceleration in m/s2. So, .5 kg x 3 m/s2= 1.5 N

8 The bullfrog, Rana catesbeiana, is most closely related to the —

A spotted chorus frog, Pseudacris clarki

B Asian flying frog, Polypedates leucomystax

C northern leopard frog, Rana pipiens

D African bullfrog, Pyxicephalus adspersus

Related in biological terms means look at family, genus, species.

A spotted chorus frog, Pseudacris clarki

B Asian flying frog, Polypedates leucomystax

C northern leopard frog, Rana pipiens

D African bullfrog, Pyxicephalus adspersus

• Genus is always a capital letter,

species is lower case.

• Most closely related would be in the

same genus, Rana.

• ANSWER? • C

9 Four lab groups measured the volume of acid required to neutralize a standard solution of sodium hydroxide base. Which of the groups measured the

volume with the highest precision?

What equipment is used to measure volume?

• In A, they are using two flasks. Not very precise markings!

• B is better, at least they are using a graduated cylinder.

• C is a bad choice, since most test tubes have no markings for volume.

• D is the best choice as the small volume markings on the burette gives the most precise measurement.

10 Which process best shows the conversion of solar energy to chemical energy?

A Prevailing winds causing windmills to spin This is thermal (wind) to mechanical (spin)B Green plants making their own food This is solar (photosynthesis) to chemical (food)

!!!!C Uranium producing heat to make steam This is nuclear (radioactive U) to thermal

(steam) D Tides generating electricity This is mechanical (tide of water moving a

generator) to electrical

11 An advertisement claims that patients can be cured of the common cold in 48 hours by vitamin C tablets with secret mineral supplements. In a scientific experiment to test these claims, which data can be considered irrelevant?A The amount of vitamin C in each tabletB The severity of the patients’ cold symptomsC The chemical formula for vitamin CD The amount of time before symptoms improve

What doesn’t matter to the test?

A The amount of vitamin C in each tablet This should be a controlled variable! B The severity of the patients’ cold symptoms This would be very hard to control, but a large

experimental group should allow for differencesC The chemical formula for vitamin C Compound formulas NEVER change so this is

our answer it is irrelevant!!! D The amount of time before symptoms improve This is what we are testing, it is most relevant.

12 All of these can affect the rate at which a solid dissolves in water except —

A decreasing air pressure

B stirring the water

C increasing the temperature of the water

D using larger crystals of the solid

The three methods to increase the rate of solution for a solid are?

• Heat it! C

• Crush it! D slows it

• Stir it! B

• So this eliminates choices B, C & D

• Which will NOT change it?

• A

Answer choices were:

A decreasing air pressure

B stirring the water

C increasing the temperature of the water

D using larger crystals of the solid

K + H2O KOH + H2

13 What is the coefficient for H2O when the above equation is balanced?

• A 1

• B 2

• C 3

• D 4

To balance this equation, make water HOH, then you will see that you need 2 H and get 2 OH groups.

That means the KOH gets a coefficient of 2, the K gets a coefficient of 2 and

The water must also get a coefficient of 2.

H OH 22 2

14 The diagram shows physical changes that

occur in the water cycle. Which of these shows

condensation?

A Q

B R

C S

D T

PrecipitationRun Off of ground waterEvaporation

15 The table shows environmental factors and soybean production for three regions.

Which of the following probably accounts for the decrease in soybean yield in Region 1?

A High levels of ozone damaged the soybean plants, decreasing the average yield.

B Low rainfall amounts failed to meet the plants’ moisture needs and inhibited growth.

C Poor mineral levels found in the soil in that region limited the soybean harvest.

D Higher-than-normal rainfall increased pest activity, decreasing the average yield.

What do you have to know?

• 1st you really only have two choices, decreased rainfall, or O3 level.

• Since the rainfall did not decrease consistently (it actually increased in 1999) that would not be a good answer.

• Therefore, it must be the O3, which is the chemical formula for ozone.

• Answer? A

16 According to the periodic table, which element most readily accepts electrons?

• A Fluorine• B Nitrogen • This is a nonmetal, so it

accepts electrons but it will also share them as in NO3

1-.• C Arsenic • This is a metalloid, so it only

sometimes accepts electrons.• D Aluminum • This is a metal so it donates

electrons.

Fluorine only needs 1 electron to complete its shell of 8, so it will accept it from any other element very very very easily. This periodic property increases as you move up and left in the table, except for the Noble Gases.

What is the DNA base pair rule?

17 If the template of a strand of DNA is 5' AGATGCATC 3', the complementary strandwill be —A 3' TCTACGTAG 5'B 5' CTCGTACGA 3'C 3' AGATGCATC 5'D 5' AGACGTCTA 3'

In DNA A to T and T to A, C to B and B to C where

A = adenine, T = thymine, C = cytosine, and B = guanine

5' AGATGCATC 3‘

TCTACGTAG

• Base pair each letter by the above rule.

• So the answer is:

• A

Density = Mass / Volume THIS IS FROM THE FORMULA PAGE18 A block of maple wood with a volume of405 cubic centimeters and a density of0.67 g/cm3 is sawed in half. The densityof the two smaller blocks is now —A one-fourth the original densityB one-half the original densityC two times the original densityD the same as the original density

If the block is cut in half, you cut the mass in half AND you cut the volume in half, so Mass/2 or Volume/2

Mass x 2 (which is really 1) so . . . .

Volume 2

19 If a cat has 38 chromosomes in each of its body cells, how many chromosomes will be in each daughter cell after mitosis?

• A 11

• B 19

• C 38

• D 76Mitosis is the normal division of any body cell, so the chromosomes replicate exactly and then separate into two identical cells. So the answer is

C

20 A ball moving at 30 m/s has a momentum of 15 kg·m/s. The mass of the ball is —

A 45 kg

B 15 kg

C 2.0 kg

D 0.5 kg

Formula Page says that Momentum = Mass x Velocity

So 15 kg.m/s = M x 30 m/s solving for M it is:

21 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?

What do you know? Identical containers, and same volume of water.

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 -15°C and as a liquid at 25°C?

D How does the rate of evaporation change when a different container is used?

• D is out since the containers are identical.

• C has nothing to do with the rate of evaporation so it is out

• B is out, because the boiling point of a substance is a physical property that can identify a substance, so it is out

• That leaves A, which asks about temperature and a rate “slow”.

A circulatory system

B integumentary system

C excretory system

D endocrine system

22 Nutrients from digested food move from the digestive system directly into the —

Endocrine system does not transport anything. So . . .

Excretory system gets rid of waste CO2 and C2O, not food. So . .

Integumentary system holds organs and tissues in place. So. . .

The Circulatory System carries everything to every cell, so it is . .

23 An environmental-science company measured the ozone pollutant levels at two different locations in a metropolitan area. Which statement is best supported by these data?

Look for the unsafe levels and where and when they occur.

Both occurred on 7/15 at a temperature of 38 oC, so . .

A Lower fuel efficiency and northerly winds in the winter increase ozone pollution the most.

B Northwest winds in the spring transport ozone pollution into the metropolitan area.

C High summer temperatures and southerly winds contribute to high levels of ozone.

D Heavy use of automobiles changes ozone levels the most.

This is true, however not supported by the data in the table since both downtown and northwest areas had increases.

winterspring

24 One tuning fork is struck and placed next to an identical fork. The two forks do not touch. The second tuning fork starts to vibrate because of —

A interference

B the Doppler effect

C resonance

D standing waves

The 2nd fork is struck by the waves at it’s natural frequency since it is identical and begins to vibrate (definition of resonance)

Interference means that both tuning forks were struck and where the waves meet, if they are synchronized crest to crest, they will be louder, and where they are crest to trough they will cancel each other.

The Doppler Effect requires that the source of the sound is moving and will result in a change of perceived pitch by the receiver as the source moves towards and then away from it.

A standing wave is not moving, so it would not even effect another object.

Higher pH levels means?25 Two clear solutions are placed in separate

beakers. The first solution has a pH of 4, and the pH of the second solution is unknown. If

the two solutions are mixed and the resulting

pH is 5, the second solution must have —

A fewer suspended solids

B a lower temperature

C more dissolved salt (NaCl) particles

D a higher concentration of OH– ions

Solutions are homogeneous and have no suspended solids. Nothing is mentioned about temperature so B is invalid. NaCl solutions are neutral so have no effect on pC.

26 When a sea urchin egg is removed from the

ocean and placed in freshwater, the egg swells

and bursts. Which of these causes water to enter the egg?

A Coagulation

B Sodium pump

C Active transport

D Osmosis

Means to clump together – Incorrect

Sodium is not being moved – Incorrect The egg would not use energy

to do this since it kills the cell.

This is the movement of water from an area of high concentration (the fresh water) to low concentration (inside the Salt Water Urchin EggSalt Water Urchin Egg)

27 Clown fish are small reef fish that seek protection from predators by sheltering themselves among the stinging tentacles of sea anemones. Clown fish are very territorial and can potentially scare off predators of sea anemones. This relationship is an example of --

A neutralism

B mutualism

C parasitism

D commensalism

This is not a type of symbiosis Incorrect

Neither is harmed so this is incorrect

Means only one is being helped and the relationship has no effect on the other – also incorrect

Since both are helped, it is of mutual benefit or

28 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 theexistence of life on Mars is likely becauseMars’s atmosphere is 95% carbon dioxide.

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?

When testing an hypothesis, there should be only one variable changed at a time. If this is not possible, then all possible reasons for an outcome need to be considered. In this case, carbon dioxide can be produced by chemical reactions other than cellular respiration, which is a biotic process. That is why answer B is the best answer.

29. Why is the sum of the products’ energy in this reaction less than the sum of the reactants’ energy?

A.Energy is given off as heat.

B.The products absorb available energy.

C.Energy is trapped in the reactants.

D.The reactants’ energy is less than the melting point of glucose.

What does this equation represent?

Cellular respiration, which is a type of combustion reaction.

What is given off by combustion?

Heat energy, or Answer A.

30 Which of these groups of organisms would most likely have accumulated the largest concentration of a long-lasting chemical pollutant in their bodies?

A Phytoplankton

B Zooplankton

C Lake trout

D Gulls

Since the Gulls are at the top of the food web, they would have the highest accumulation of everything but energy.

31 According to the law of conservation of mass, how much zinc was present in the zinc carbonate?

A 40 g B 88 g C 104 g D 256 gSince matter can not be created or destroyed in chemical reactions, the mass on both sides of the arrow must be equal. So 64g + 192g = 256g and 152 g + Zinc = 256g

There must be 104g of Zinc. Answer C.

32 If the properties of water were to change so that the solid form was denser than the liquid form, organisms living in a cold pond environment would be less likely to survive because water would no longer —

A dissolve enough oxygen from the air

B produce solutions containing vital Nutrients

C remain neutral, instead becoming highly acidic

D produce a floating insulating layer of ice

More gas dissolves at lower temperatures so A is False

Changing a physical property does not change what it contains chemically so B is False

Water is neutral no matter what state it is in, solid, liquid or gas, so C is False. That leaves: D

Ice floats on water, and if it was more dense, it would sink, not float.

Use the formula page! PE = mgh

33 What is the potential energy of the rock?

A 59,900 joules

B 64,600 joules

C 93,100 joules

D 121,600 joules

m = 95 kg g = 9.8 m/s2 h = 100 m

95 kg x 9.8 m/s2 x 100 m =

93,100 joules C

Heat moves by conduction in solids since the particles are close together

and vibrate. . . 34 Heat convection occurs in gases and

liquids. Heat convection does not occur in solids because solids are unable to —

A absorb heat by vibratingB transfer heat by fluid motionC emit radiation by reflecting lightD exchange heat by direct contact

Solids do radiate heat to their surroundings

A accelerated rapidly

B remained motionless

C decreased its velocity

D gained momentum

35 If a force of 100 newtons was exerted on an object and no work was done, the object must have —

Work = Force x Distance

Work = 0 Force = 100 N so

0 J = 100 N x d

distance must be 0

It did not move!

36 The diagram shows an electric motor lifting a 6 N block a distance of 3 m. The total amount of electrical energy used by the motor is 30 J. Cow much energy does the motor convert to heat?

A 9 J

B 12 J

C 18 J

D 21 J

Work Output = Resistance Aorce x Resistance Distance

Workout = 18J = 6N x 3m

Work Input = 30J done by the motor

The difference is lost as heat due to friction, which is 30J – 18J = 12J

Answer B

37 At which temperature do KBr and KNO3 have the same solubility?

A 27°C

B 48°C

C 65°C

D 80°C

Other tutorial sessions begin tomorrow. Come review the types

of questions you missed.

Chemistry: Obj. 4 Physics: Obj. 5 Biology: Obj. 2 & 3