Science

The half-life of cadmium-109 is 464 days. A scientist measures out a 256 gram sample. Approximately how many grams of cadmium-109 would remain after 1,392 days?

• 32

• 64

• 2048

• 1024

A scientist is measuring the mass of two boron atoms. One atom has a mass of 10 units. The other atom has a mass of 11 units. Which subatomic particle needs to be removed from the model to represent a boron atom with a mass of 10 units?

• Electron

• Nucleus

• Neutron

• Proton

The elements neon and argon are not reactive. Which hypothesis BEST explains this?

• They are not stable atoms.

• They are not readily available on Earth.

• They tend to give up all of their valence electrons easily.

• They have the maximum possible number of electrons in their outermost shell.

Metals in group 1 on the periodic table most commonly form which type of ion?

• 2- ion

• 1- ion

• 1+ ion

• 2+ ion

Use this chemical equation to answer the question. _CuS + _KCl -> _CuCl₂ + _K₂S What coefficient of KCl will balance the equation?

• 1

• 2

• 3

• 4

Use this chemical equation to answer the question. _Fe + O₂ -> _Fe₂O₃ What coefficients of Fe, O₂ and Fe₂O₃ will show that matter is conserved in this chemical reaction?

• 2, 1, 2

• 2, 3, 2

• 4, 1, 2

• 4, 3, 2

A student pulls a lever down 4 m. The lever lifts a box that weighs 20 N up a distance of 2 m. How much work was done on the box?

• 10 J

• 40 J

• 80 J

• 160 J

Which claim about current is shown to be mathematically supported from the relationship between the voltage, the current, and the resistance?

• claim 1: I = V + R

• claim 2: I = V - R

• claim 3: I = V x R

• claim 4: I = V / R

A parallel circuit contains a battery with a voltage of 9 volts. he total resistance in the circuit is 18 ohms. Which claim about the current in the circuit can be supported mathematically from the relationships between voltage, current, and resistance?

• claim 1: the current flowing through the circuit is 0.5 amps because current is related to voltage and resistance by the formula I = V/R

• claim 2: the current flowing through the circuit is 2 amps because current is related to voltage and resistance by the formula I = R/V

• claim 3: the current flowing through the circuit is 27 amps because current is related to voltage and resistance by the formula I = R + V

• claim 4: the current flowing through the circuit is 162 amps because current is related to voltage and resistance by the formula I = VR

Charlie lifts a box with a force of 500 N and sets it on a table top 1.2 m above its starting position. Lauren pushes an identical box up a 5 m ramp from the floor to the top of the same table. Which person did more work?

• Charlie did more work.

• Lauren did more work.

• Both Charlie and Lauren did the same amount of work.

• The size of each individual must be known to determine who did more work.