Esperar que

Jessica took a mylar balloon outside on a very cold day. As she waited for the bus the balloon began to shrink. What is the best explanation of this?

A.) As the particles became cooler, they lost energy and moved less, resulting in less pressure on the balloon.

What is one way in which fission differs from fusion?

A.) Fission splits nuclei, fusion combines nuclei.

What is the chemical formula for potassium oxide?

A.) K2O

Which phrase can accurately be placed in the middle, within both circles?

ionizes in water

A magnetic field is created by a charged particle that is

C.) moving

Barium-142 is used as a GI radiocontrast agent. After 1.25 hours, 9.25 μg remains in the patient. Determine the original dose given the half-life of Ba-142 is 10.6 minutes.

1,180 μg

A burning candle is covered by a jar as shown in the picture. The whole arrangement has a mass of 500 g. What will be the approximate mass of the arrangement when the candle is completely burnt, after four minutes?

500 g

Students in Dr. Lee's class were conducting solubility experiments using sucrose and water. Students began with room temperature water (22oC) and then heated the water to boiling. They calculated the amount of sugar that could be dissolved in the water as the temperature increased. Marge and Bill lost their data and were trying to graph their results from memory. Help them out! Which graph is the MOST reasonable representation of their expected data?

A

Which example best demonstrates how unbalanced forces change the speed of an object's motion?

A child on a bicycle braking at a stop sign.

Based on the Law of Conservation of Matter, describe the relationship between the mass of the reactants and the mass of the products.

A.) The mass of the reactants equals the mass of the products.

If you wanted to design an experiment to show that the solubility of sugar in tea varies according to the temperature, what variable would remain constant?

A.) Volume of tea

An isotope has the same ________, but a different ________ .

A.) atomic number, mass number

Which flow diagram BEST explains the energy transformations that occur within an automobile running on diesel?

A.) chemical energy → kinetic energy→ heat energy

When ironing clothes, the primary method of heat transfer is

A.) conduction

An atom either gains or loses _______ to become an ion.

A.) electrons

Using the periodic table, determine which element these characteristics MOST LIKELY describe.

A.) fluorine

Two classes of students line up for a tug of war. If both classes have the same number of students on a team, what other factor is very important so one team can win?

A.) total mass of each team

Three light bulbs are connected to a battery in a series circuit. How will the bulbs behave if the circuit is closed?

All three bulbs will glow.

Elaborate on the changes in molecular motion of particles as they change from solid to liquid to gas.

As the phase changes occur, the freedom of motion of the particles increases.

An electrical generator is an important component in a power plant. Which BEST shows the energy transfer diagram for a generator?

B.)

Use the chart to determine the half-life of Carbon-14.

B.) 5,700 years

Elaborate on the fundamental difference between fission and fusion reactions.

B.) Fission is a decomposition reaction while fusion is a synthesis reaction.

Beet juice is added to a unknown solution and changes color from red to purple. Curry powder, added to the same solution, turns a deep red color. What can you tell about the hydrogen/hydroxide ion concentration of the unknown liquid?

B.) H+ low and OH- high

In baseball, a home run means the batter has hit the baseball into the stands, beyond the baseball field. Compare the force of the batter when bunting the ball into the in-field versus hitting a grand slam.

B.) The force is much less when bunting into the in-field.

Describe the mass of the reactants and products given the balanced chemical reaction.

B.) The mass of the reactants equals the mass of the products.

Based on the images seen here, identify which phase of matter would transmit sound waves the fastest, and why?

B.) The solid would transmit the fastest because the particles are closest together.

A member of the marching band tunes their trombone inside their school. When they walk out to the field the instrument goes out of tune. What is the best explanation for this?

B.) The speed of sound decreases with a decrease in temperature.

Phthlates are a family of chemicals added to plastics to make them more pliable as well as to cosmetics and other toiletry items. Exposure to these chemicals have been linked to developmental problems and cognitive deficits in infants and children. What statement correctly describes the concern about phthalates?

B.) These chemicals are found in many common household products.

Newton's Second Law of Motion is F = ma. Closely related to this is Hooke's Law, F = -kx, which describes the force needed to restore the displacement of a "rigid" body, such as a spring. Therefore, Hooke's Law is a measure of a body's

B.) elasticity.

The light bulb transfers electrical energy into light. What is one type of energy that is also generated that is NOT a desired effect?

B.) heat

The distance from point A to point B is known as the

B.) wavelength

Electrical energy can be transformed into other types of energy. We often experience this transformation of energy in our everyday lives. Which example represents a conversion from light energy to electrical energy?

C.

A scientist observes that the particles of a gas are arranged as shown. If the gas begins to condense into a liquid, which particle arrangement would MOST LIKELY be observed?

C.)

Consider the pH range of various solutions. How many of the solutions were in the basic range on the pH scale?

C.) 3

If there are 4 grams of reactant, how many grams of product are produced by the chemical reaction?

C.) 4 grams

Liz puts a 1 kg weight and a 10 kg on identical sleds. She then applies a 10N force to each sled. Which does not explain why the smaller weight accelerate faster?

C.) The acceleration depends directly on the mass of the object.

Sal connected four light bulbs in a parallel circuit. If Sal adds another light bulb, what is true about the current in each bulb?

C.) The current in each bulb remained the same even though another bulb was added.

In old western movies, cowboys often would put their ear to a train track to listen for an oncoming train. What benefit would this method provide over listening for a train by listening for sound through the air?

C.) The sound would reach him sooner.

If you slow the motion of water molecules down, they are more likely to become

C.) colder

Identify the case where water is NOT the solvent.

C.) humid air

Comparing Wave A (black) to Wave B (green), Wave A has a

C.) longer wavelength.

When carbon dioxide is formed, one carbon atom forms double covalent bonds with two oxygen atoms. Carbon dioxide is considered

C.) more stable than individual atoms as now the outer energy levels of all atoms are filled.

Which statement accurately describes covalent bonds?

Covalent bonds are are typical of carbon compounds.

It is almost time for the summer Olympics. The Olympic hammer throw is a throwing event where the object is to throw a heavy metal ball attached to a wire and handle. The name hammer throw comes from an older contest where men threw a sledge hammer. The hammer have different weights, ranging from 16 pounds down to 8 pounds. Imagine there are four hammers to throw: 16, 12, 10, and 8 pounds. If you throw each hammer with the same amount of force, which hammer will move the shortest distance?

D.) 16 pounds

Which observation would be evidence that heat was transferred by radiation?

D.) A car with the windows rolled up gets very hot on a summer day.

In an automobile, a 12 Volt battery simultaneously supplies electrical energy for the ignition, lights and radio. This electrical circuit must be

D.) DC in parallel.

You hop on the carousel horse. The attendant flips the switch and you move up and down, around and around. When the ride ends, the attendant again flips the switch. The up and down motion stops, as you continue to move in a circular motion, gradually slowing to a stop. Why?

D.) Mechanical systems need an external energy source to maintain their motion.

Sulfur hexafluoride is represented by which formula?

D.) SF6

Describe how resistance affects the flow of current in a circuit.

D.) The flow of current in a circuit is reduced by resistance from collisions of the electrons within the wire.

Jaime is picking out a skillet for his mother as a birthday present. He is looking at two skillets, one with a plastic handle and one with a metal handle. Thinking just about safety, which handle would you recommend to Jaime and why?

D.) The plastic handle, because it is a good insulator.

In this electric motor, an electric current causes the coil to rotate, changing

D.) electrical energy to mechanical energy.

Sound waves require a medium to travel through, such as a solid, liquid or gas because

D.) sound is molecules bumping into one another.

Which would be best categorized as heat transfer by conduction?

Feeling the heat from a light bulb with your hand when touching the bulb.

Newton's laws of motion work well for ordinary situations on earth. However, these laws of motion do not work for all cases. Under what condition will Newton's second law not work?

For objects at extremely fast speeds.

Rob is attempting to dissolve rock salt in warm water but it is a slow process. How could he most effectively increase the rate of solution of the rock salt?

Grind the rock salt into smaller pieces.

An electromagnet is created using a battery, an insulated copper wire and an iron nail. The wire is wrapped around the nail 20 times and attached to the battery. Which pair of changes will definitely increase the strength of the electromagnet?

Increase the voltage of the battery and increase the number of turns of the coil.

Michael is playing with two horseshoe magnets. He is trying to get them to touch, but they will not regardless of how hard he tries. Why will the magnets not come in contact?

Michael is trying to touch north poles to north poles.

Amy measured the tire pressure of her truck that was parked outside after a cold night. The daytime temperature reached a nice 65 °F. Assume Amy's tires do not have any leaks. Explain the change in tire pressure.

The air molecules heated inside the tire causing them to move faster exerting more pressure on the inside walls of the tires.

What is going to happen to a balloon filled with helium that is left in a car over night when the temperature drops approximately 20 degrees? (There are no holes in the balloon.)

The balloon is going to look somewhat deflated due to the decrease in volume.

A student is told that both energy and mass must be conserved in every chemical reaction. She measures the mass of Hydrochloric acid and a zinc strip separately. She then places the zinc strip into the acid and bubbles form as the zinc looks like it disappears. The combined mass afterward is less than the original. Which of these can explain this result?

The bubbles indicate that a gas is created and mass is loss as it escapes from the container.

Describe what the heating curve of ethanol shows about the rate of temperature increase and the enthalpy of vaporization.

The enthalpy of vaporization is unaffected by the rate of temperature increase.

As light slows down, it bends or refracts. The index of refraction helps predict the amount of bending. How are the speed of light and the index of refraction related?

The index is inversely proportional to the speed of light in the medium.

Which is an accurate description of what occurs when a log burns?

The molecules present in the log are transformed into molecules that contain less energy than the original molecules. The energy difference is the heat of the fire.

Four wrestlers step on a scale for a tournament. Wrestler A weighs in at 170 pounds; wrestler B weighs in at 168 pounds; wrestler C weighs in at 171 pounds; and wrestler D weighs in at 169 pounds. Which of these wrestlers experiences the greatest force due to gravity?

Wrestler C

The planet Jupiter has an acceleration due to gravity that is approximately 2.4 times as much as the earth (23.2 m s2 ). Which of these statements is true regarding if you were to travel to Jupiter and land on its surface?

Your weight would increase by a factor of 2.4.

Use the IUPAC nomenclature rules to give the name for this compound - Al2S3.

aluminum sulfide

Elements are arranged in groups by similar atomic structure on the periodic table. This allows for an element's properties to be predicted based on general periodic trends. One of these trends, electronegativity, increases up a group and to the right along a period and can be defined as the atom's ability to _______.

attract a bonding pair of electrons toward itself.

CuCl2 Determine the name of this compound according to IUPAC nomenclauture.

copper (II) chloride

Why can television satellites, which broadcast information as electromagnetic radiation, send signals from the vacuum of space?

because electromagnetic radiation does not need a medium to travel through

Ben helped his parents load boxes and furniture onto the moving truck. He easily carried several boxes out of the house and up a ramp into the truck. Then loaded small pieces of furniture by pushing them up the ramp. Finally, Ben tried to move the refrigerator. He pushed and pushed, but it did not move. Why?

because the refrigerator was much heavier than the other objects

Your mother has an unlabeled bottle of clear liquid in the refrigerator. You ask your mother about it, and she tells you that she bought it at the store for you to drink but the label must have fallen off. You pour a small cup of the liquid and taste it, and it has a distinctly sour flavor. The pH of this liquid is MOST likely

below 7

If you put a pencil in a cup of water, it looks as if it is bent and larger in the water. This is because waves

change direction when they change mediums.

A new type of oven that cooks food quickly and more completely is the convection oven. The key difference in this type of oven and a regular oven is that it

circulates the hot air.

The element germanium is a lustrous, hard, grayish-white solid in the carbon group. It is a semiconductor with an appearance similar to elemental silicon. Based on these facts, we should classify germanium as a

metalloid

A substance with a pH of 9 has

more OH- ions than H30+ ions.

The picture shown shows a practical application of

nuclear energy.

The nucleus of an atom contains which subatomic particles?

protons and neutrons

Which waves move by replacing one particle with another?

sound waves

Conduction is the process in which

the collisions of molecules within a substance transfer heat energy.

Observe the image above. Two fire trucks with sirens speeds towards and away from an observer. Which statement is true involving the Doppler effect observed by the observer?

the fire truck traveling towards the observer produces a higher than normal apparent siren frequency

Antoine Lavoisier found that mass was conserved in chemical reactions when he saw that

the mass of the products was the same as that of the reactants.

In 1831, Michael Faraday was the first to realize that an electric current could be induced by passing a magnet through a coil of copper wire. Which factor is MOST essential for the induction of the electric current?

the movement of the magnet relative to the coil

Two people must have the same speed and velocity if

they are jogging side by side at 5 m/s.

The change in electric potential energy per unit charge is

voltage.