## Research into nuclear fusion will likely require a large investment of time and money before it might be used as an energy source. Which statement best describes the benefits that would make the investment worthwhile?

Research into nuclear fusion will likely require a large investment of time and money before it might be used as an energy source.
Which statement best describes the benefits that would make the investment worthwhile?

A) Fusion requires a large amount of energy and occurs in stars.
B) Fusion produces large amounts of energy, and the fuel is found on Earth.
C) Fusion produces no radioactive waste, and the fuel is plentiful.
D) Fusion requires little energy to begin and would continue through a chain reaction.

## Atoms have the same number of electrons as what other particle?

Atoms have the same number of electrons as what other particle?

A. Protons
B. Neutrons
C. Photons
D. Atomic mass

## An oxygen gas is flowing through a 10m circular tube length with a radius of 16cm. Oxygen concentrations in the pipe ends are 30 kg/m^3 and 10 kg/m^3. The diffusion constant of the oxygen at 20 ° C is 1.8 x 10^-5 m^2/s.

An oxygen gas is flowing through a 10m circular tube length with a radius of 16cm. Oxygen concentrations in the pipe ends are 30 kg/m^3 and 10 kg/m^3. The diffusion constant of the oxygen at 20 ° C is 1.8 x 10^-5 m^2/s.

(a) Calculate the diffusion flow rate

(b) How many kilograms of oxygen will flow through this tube in 15 minutes?

(c) What is the oxygen concentration 2m away from the end of the tube where there is high concentration?

(d) How long will it take 100 kg of oxygen to travel this tube?

## Scientists are trying to produce a chemical reaction using two substances. After observing the substances, they realize that there is not enough energy to make the reaction they had hoped for. In this case, what would they need to add to the mixture to produce a quicker reaction?

Scientists are trying to produce a chemical reaction using two substances. After observing the substances, they realize that there is not enough energy to make the reaction they had hoped for. In this case, what would they need to add to the mixture to produce a quicker reaction?

A) A base
B) An acid
C) UV light
D) A catalyst

## In the four-stroke internal combustion engine, fuel is ignited during the ~

In the four-stroke internal combustion engine, fuel is ignited during the ~

A. Compression

B. Power

C. Intake

D.~ Exhaust stroke.