Mrs. Daneshmand A. the products of a reaction B. elements created by a reaction C. phase changes taking place during a reaction D. the number of molecules involved in a reaction Answer is A Answer is B Why did the balloon expand? A. all of the water evaporated to form a gas B. the gas in the bottle expanded as it became warmer C. some of the gas in the bottle condensed to liquid water D. the water expanded into the balloon as it became warmer. Answer is B What is the identity of the unknown substance? A. aluminum B. gold C. iron D. lead Answer is D A g/mL B g/mL C g/mL D g/mL Answer is A A. heating a block of ice to form liquid water B. heating a tungsten wire until it flows brightly C. adding sugar crystals to water to form a clear, colorless liquid D. passing an electric current through water to form hydrogen and oxygen Answer is D A. physical change B. chemical change C. solute being dissolved D. new substance being formed Answer is A A. hydrogen ion B. hydronium ion C. hydroxide ion D. hydrochloride ion Answer is C A. scientists rename old elements B. scientists discover new elements C. stars produce new elements that travel to Earth D. past mistakes are corrected in identifying elements Answer is B A. group 1 B. group 3 C. group 16 D. group 18 Answer is D A. be in the same group B. be in the same period C. have nearly the same mass D. have the same number of protons Answer is A What was an organizing principle in this grouping at that time? A. atoms of the three elements had approximately the same mass. B. the three elements react the same way with other elements. C. the elements have the same number of valence electrons D. these three elements are all gases at room temperature Answer is B A. chemical B. mechanical C. potential D. kinetic Answer is D As the engine operates, which of these remains constant? A. the masses of compounds found in the engine B. the amount of heat in the engine C. The total mass of gasoline D. The total amount of energy Answer is D A. gold B. helium C. sodium D. aluminum Answer is B What characteristic do these elements have in common? A. atomic mass B. negative electrical charge C. number of neutrons D. full valence electron shells Answer is D A. they tend to form covalent bonds with other elements B. they have one, two, or three valance electrons C. they have low melting and boiling points D. they tend to form negative ions Answer is B A. 10 km/h in the direction of bus A B. 20 km/h in the direction of bus B C. 15 km/h in the direction of bus A D. 10 km/h in the direction of bus B Answer is: A Observers Descriptions 1Train is moving to the right at 100mph 2Train is moving to the left at 100mph 3Train is moving away from him at 100mph 4Train is moving towards him at 100mph What reason best explains the differences in observers descriptions? A. they are each observing a different train B. they are observing from different locations C. some observers have seats that are closer to the trains. D. some observers are moving while others are standing still. Answer is: B Which best explain this difference? A. velocity varies with the compass direction of motion B. measurement error causes multiple observations of motion to conflict C. all motion is relative to the frame of reference chosen for measurement D. acceleration and velocity have different values because they are different measure of motion. Answer: C A. are in the same period B. are in the same family C. have the same number of electrons D. have the same atomic mass number Answer is B A. number of valence electrons B. chemical properties C. atomic number D. ionic radius Answer is B Both cars are traveling at 55mph in the same direction. How would the relative motion of car A appear to a person traveling in car B? A. not moving B. moving faster C. moving slower D. going backwards Answer is A How much work was done by the forklift to lift the boxes? A. 200 J B. 500 J C J D. 10,000 J Answer is C A. wavelength B. magnitude C. amplitude D. frequency Answer is C A. one-quarter the length of wavelength B B. one-half the length of wavelength B C. equal to the length of wavelength B D. four times the length of wavelength B Answer is D In order to escape the gravity at the surface of Earth, the chemical energy is converted to which type of energy? A. kinetic B. nuclear C. electrical D. geothermal Answer is A A. two cars two meters apart B. two bricks two meters apart C. a brick a car one meter apart D. a brick and a pencil two meters apart Answer is A Which best explains why the ice formed? A. the mass of the water changed B. energy was released from the water C. a chemical reaction occurred at the surface of the water D. molecules were exchanged between the environment and the water Answer is B If placed on a table, what is the net normal force of the block? A. 3 N B. 4 N C. 6 N D. 8 N Answer is B Which property of the ball is constant? A. speed B. acceleration C. direction D. momentum Answer is A A. particles travel from right to left along the wave B. particles travel from left to right along the wave C. particles move back and forth parallel to the wave D. particles move back and forth perpendicular to the wave Answer is D