Solution Set for Science Quizzes

SCIENCE QUIZZES SOLUTION SETS

GENERAL SCIENCE 1) C. force and distance Work is equal to force times distance (displacement). W=fxd 2) A. salt water is heavier than water. Density is directly proportional to mass. D = M/v 3) B. Kinetic energy is energy in motion. 4) C The higher the object is, the greater is the potential energy. 5) C. Convection takes place when there is a movement of air from hot place to cold place. The sea and Land differ in temperature at night time and daytime, the reason why there is sea breeze and land breeze at daytime and night time respectively. 6) A. 5.8 mL Using water displacement method, Vobject = Vfinal - Vinitial = 23. 6 – 17.8 = 5.8 mL 7) A. 100 g = 1 N; 17.6 g x (1N/100 g) = 0.176 N 8) D. Work = force x distance = 500 N x 10 m = 5000 Nm = 5000 J 9) A. Ionosphere is the layer of the atmosphere composed of charged ions that returns radio and tv signals back on earth. 10) C. during a stormy day, heavy black clouds are seen in the sky. these are nimbus clouds. 11) D. many years of stress on the rock may fracture the crust causing one portion to slide upward or down ward with respect to the other. 12) C. mountain is formed when two plates move toward each other. 13) F = 9/5 __C + 32 F = 9/5 (30) + 32 F = 86 (c) 14) A CFC is not a greenhouse gas. It only damages the ozone layer. 15) C = K – 273 C= 0 – 273 ; 0 Kelvin = -273 C (d) 16) C. the independent variable is the factor that is being changed in the experiment. The amount of moisture is the factor being changed in the experiment given. 17) C. based on the data table, it can be concluded that molds grow best in cold places. 18) C. using the scientific method, we can let Bisuke and Killua punch the same object a number of times and compare the damage done. (You would not want to be hurt in an experiment, right?) 19) A. the sun’s reflection on the moon gives the moon the ability to shine. 20) A. when the moon is closer to the earth, the greater the effect of gravity. 21) A. the crust is the hard outer shell of the earth. 22) C. A composite volcano is formed from alternating quiet and violent eruptions. An example is Mount Mayon. 1g  0.015 g 23) B. 150mg  1000mg 24) B. blue star is the hottest star followed by the white star, yellow star and finally the red star. 25) B. Venus is called the win planet of the earth because they almost have the same size. 26) D. The smallest, coldest and the outermost planet in the solar system is Pluto. 27) B When two plates (sea floor )move apart (diverging) magma comes out and accumulate forming a mountain range under the sea called the mid-ocean ridge. 28) C. When engines burn fossil fuels, carbon dioxide, a harmful gas is produced. 29) B. The ozone layer absorbs a portion of the radiation from the sun, preventing it from reaching the earth.

30) On clear calm evenings, temperature differences between a body of water and neighboring land produce a cool wind known as the land breeze that blows offshore.

BIOLOGY 1) C. cells grouped together form tissue; tissues working together form organs; organs working together form a system 2) B. the products of photosynthesis is stored in the form of starch in plants. 3) C. cell walls of plant cells contain a high concentration of cellulose, a substance that cannot be digested properly by human beings. 4) B. mutualism is the process in which both organisms are benefited from the interaction. Plants are being benefited when animals release carbon dioxide which is needed by plants to make food. Animals are also benefited when plants produce oxygen which is needed by animals in order to live. 5) A. Oryza sativa is the scientific name of rice. The scientific name is taken from the genus and the species. 6) C. In the levels of classification if both organisms belong to the same class, they must also belong to the same phylum and kingdom for these are the levels higher than the class. 7) C. A prokaryotic cell does not have endoplasmic reticulum. It does not have a membrane bound organelle. 8) C. The skin is composed of epithelial tissues wherein cells are compactly arranged. 9) D. Genes are hereditary information contained in the DNA. DNA is deoxyribonucleic acid. 10) C. coevolution is the relationship that refers to the partial dependence of evolutionary changes of an organism to another specie which it has a close ecological relationship. 11) A. Not all vertebrates are warm blooded animals. Some are cold blooded like fishes and reptiles. 12) D. coiling up of chromatin, replication of DNA strands and movement of the chromosomes towards the center all happen during mitosis. 13) D. survival of the fittest suggests that stronger organisms with more favorable characteristics are more possible to survive and live longer than the weaker ones. 14) A. a plant cell has a cell wall, animals cell doesn’t have. 15) A. a prokaryotic cell does not have a true nucleus. It has chromosomes in the DNA and it also has a cell membrane that separates itself from the environment. 16) B. simple multicellular animals with tissues but no distinct organs; also known as sponger are under the phylum Porifera. 17) A. Notochord is the flexible supporting rod of vertebrates. 18) C. The plasma membrane is composed of two layers of phospholipids molecules. 19) C. White blood cells are the soldiers of the body that fight harmful bacteria that enter the body. 20) B. As the energy level in the food pyramid rises, the transfer of energy decreases to one tenth of the initial energy in evry stage. 21) B. Metaphase is that stage in meiosis when the paired homologous pair line up along the equatorial plate forming the spindle fiber 22) D. Hibernation and estivation are both response to extreme temperature. 23) A. When the animal’s temperature drops, the animal may die. 24) B. The nervous system carry nerve impulses to and from the brain. 25) D. When organisms like cockroaches are exposed to some insecticides for a long time, they are able to create permanent mutation in the next generation giving insect’s resistance from that insecticide. 26) D. Vascular organs are composed of xylem and phloem (vessels) that transport water and nutrient to the plant. 27) C. Mammals are vertebrates that have mammary glands. 28) A. Carbon and oxygen cycle is maintained by respiration. Oxygen is taking in and carbon dioxide is given out by animals during respiration. 29) D. A cold blooded animal has body fluid temperature that adapts to environmental changes. 30) B. Sexual reproduction involves the use of gametes or sex cells.

CHEMISTRY 1) Given: P1 = 2 atm V1 = 100mL T1 = 299 K

V2 

P2 = 1 atm V2 = ? T2 = 286 K

P1V1T2 2atm  100mL  286 K  P2T1 1atm  299 K

2) A. There are 7 valence electron in the valence shell 4. The group number can be predicted from the number of valence electron and the period number from the valence shell. Therefore, the element is in group7 & period 4 in the periodic table of the elements. 3) The balanced chemical equation is 2C6H14O4 + 15 O2  12CO2 + 14H2O C= 2x 6 =12 C = 12 H = 2 x 1428 H = 14 x 2 = 28 O = 2 x4 + 15x2 =38 O = 12 x 2 + 14 = 38 4) b. 2 HCN H=2 C=2 N=3 O=2

+

NO2



C2N2

+ NO H=2 C=2 N=3 O=2

+ H2O

5) a. ionic bond refers to the electrostatic attraction between positive( cation) and negative (anion) ions. 6) D) mass number = neutron number plus proton number = 74 + 53 = 127 7) a. proton # = atomic number = 53 8) a. in a neutral atom, the number of electron is also equal to the number of protons = 53 9) d. double replacement reaction. Fe replaces Na and Cl replaces PO4. 10) B. Calcium carbonate decomposes into CaO and carbon dioxide 11) A. Mg combines with nitrogen to produce magnesim nitride. 12) C. Zinc replaces hydrogen. 13) Given M1 = 3M V1 = 3L M2 = 6M V2 = ? M1 V1 = M2 V2

M 1 V1 3M  3 L  V2  1.5 L M2 6M

14) Given Moles of Hydrogen = ? 2.5 moles N2 Stoic Ratio : 1 N2 = 3 H2 Moles of H2 = 2.5 mol N2 x

3molH 2 = 7.5 mol H2 1molN 2

15) From no. 14, 7.5 mol Hydrogen is produced 7.5 mol H2 x 16) Given: V1 = 450 mL T1 = 30 C

2g H 2 = 15 g H2 mol V2 = ? T2 = 50 C

V2 =

V1T2 450mL  323K  T1 303K

17) Solution is the mixture that particles don not settle down, cannot be filtered, and cannot be seen by the naked eye. 18) From the combined gas law, pressure is inversely proportional to the volume and is directly proportional to the temperature. If the temperature is decreased, the pressure also decreases inside a container. 19) According to Boyle’s law, at constant temperature, the volume of a gas is inversely proportional to the amount of pressure exerted on it. If the pressure is doubled, volume will decrease. 20) The formula that indicates the local number of atoms of the elements un a compound is the empirical formula. 21) The reaction between magnesium chloride and potassium hydroxide is a double replacement reaction that produces Mg(OH)2 and KCl. 22) Orbitals (s, p, d, f) make up subshell (2s, 2p, 2d, 2f), subshells make up the shell (energy levels 1, 2, 3,…7) 23) Molarity, molality, and normality are all modes of expressing concentration of solutions. Acidity is the measure of alkalinity of solutions. 24) Based on the law of mass conservation,if 50 g of the reactants is used up in a reaction, 50g of the products will be produced. 25) Freezing carbon dioxide does not involve change in chemical composition and formation of new peoducts. Therefore, it is physical reaction. 26) Atomic number is equal to the number of protons. Mass num,ber is equal to the number of protons plus the number of neutrons. 27) In a compound, the sum of the total positive oxidation numbers and negative oxidation numbers must be equal to zero. 28) Atoms of the same elements having the same atomic number can have different mass number due to differences in their number of neutrons. These atoms are called isotopes. 29) Random movement of particles is least observable in solids. The particles are compactly arranged in solids. 30) Electrons found in an incomplete outer shell of an atom are called valence electrons.

PHYSICS 1)

2) 3) 4)

5) 6)

7) 8)

A vector is a quantity with both magnitude and direction. Displacement, force, and acceleration are all vector quantities except speed. Mmmm 1 N is defined to be 1 kg m/s2. Force = weight (gravity due to acceleration= 10m/s2) Illustration: a = 0.5 km 1.2km East b= 1.2 km c=? 0.5 c = a 2  b2 km c = 1.3 North a = ΔV / Δt = 20 m/s / 5 s a = force / mass Given : m = 2 kg a = 0.5 m/s2 F = mass x acceleration F = 2 kg x 0.5 m/s2 = 1 kg m/s2 = 1 N

= 4 m/s2

xxxxx Kinematics is the study under dynamics that deals with the space-time relationship in bodies that are in motion.

9)

Centripetal force =

mv 2 r

Given: mass = 100 kg, radius = 60 meters, v = 30 m/s

force  10)

11) 12)

13)

14) 15) 16) 17) 18)

19)

(100kg )(900m 2 / s 2 )  1500kgm / s 2  1500 N  1.5kN 60m

In baseball, if the action is the impact of the bat against the ball, the opposite reaction is the force of the ball against the bat. This satisfies the law of action and reaction. Boni Instantaneous speed is defined as the quantitative measure of the change of an object’s position over a certain amount of time. Projectile motion is defined as the movement of body launched in space without its motive power, and travels freely under the action of gravity and air resistance alone. At rest, the distance (meters) is constant, time (seconds) varries. (c) An increase in temperature and distance illutrates a car traveling at constant velocity. (b) xxxx xxxx A. Vf = Vi + aΔt is the equation for the final velocity of an object given the acceleration, initial velocity and time. Given L1 = 80 cm (from the fulcrum) L2 = ? F1 = 500 N F2 = 1500 N

L1 L  2 F1 F2 20)

xxxx

21)

KE =

L2 

L1 F2 20cm  1500 N   60cm F1 500 N

1 mv 2 2

m = 500 kg

v = 3.0 m/s

1 2 2 KE = (500kg )(9m / s )  2.25kJ 2 22) a. According to the Law of conservation of momentum, the total momentum of a system is conserved. When bodies of equal masses and equal speeds collide, they bounce back with the same speed and distance. 23) Pressure waves of frequencies above the audible frequencies are called ultrasonic waves. 24) A fish might look much nearer to the surface than it really is because light travels at a different speed on water. 25) Vv 26) Electromagnetic waves are produced by moving charges. They are transverse waves. They travel with the same speed in the absence of vacuum. They do not require a medium for transmission. 27) A. polarization is an interaction with matter in which transverse waves are restricted to a particular plane of vibration. 28) The characteristic of sound that we perceive as volume is the amplitude. 29) Light is 17 860 mph faster than light. 30) In the color spectrum, (Violet to Red) the colors are enumerated in increasing wavelength.