A few more chemistry questions?

[barend31]

1 Which statement best describes energy in an open system?

Energy and matter flow into and out of the system.

All energy and matter are contained within the system.

There is no energy in an open system; there is matter.

Matter flows into and out of the system; energy does not.
2Combustion is the process of oxidizing a carbon fuel source in the presence of

xenon.

sulfur.

oxygen.

helium.
3 Which statement best describes an isolated system?

Energy flows into and out of the system but matter is contained.

There is no energy or matter that exists inside an isolated system.

Energy is contained within the system and matter is exchanged.

Neither energy nor matter are exchanged with the surroundings.
4 The atoms and molecules in a liquid are in constant motion. As temperature decreases, what is true of the particles in the liquid?

the rate of particle movement decreases

the distance between the particles decreases

the attraction between the particles decreases

the potential energy of the particles decreases
5Often scientists who want to demonstrate chemical bonding use models with colored balls to represent atoms. The chemical models of bonding are based on what?

the individual work of JJ Thompson, creator of the Plum-Pudding model

philosophical discourse, because atoms are submicroscopic

scientific data that has been gathered through experimentation

photographs of atoms that show their different colors and sizes
6Many scientists have contributed to the current accepted atomic model. Which of the following would be a reasonable description of this current atomic model?

The model has changed very little over its entire history.

The model gradually changed as new scientific data was gathered.

The model is virtually complete and is unlikely to change much.

The model quickly and rapidly changed until technology caught up.
7 Which statement best describes the law of conservation of energy?

There is a limited amount of energy, and it remains in the same form.

New energy is created, and as it is used, it is destroyed.

Energy is neither created nor destroyed; it is transformed and transferred.

Energy is neither transformed nor transferred; it is created and destroyed.
8 Which statement best describes why an island food web could be considered a closed system?

Energy flows freely into and out of the island food web.

Energy enters and exits the system, matter does not.

New energy enters the food web, and matter is created as it moves through the web.

No energy exists outside the food web; only matter.
9 The deflection of alpha particles in Rutherford's gold foil experiments resulted in what change to the atomic model?

the addition of energy levels and orbitals to the electron cloud

the addition of a small, dense nucleus to the center of the atom

the addition of wave properties to the characteristics of an electron

the addition of neutrons to the nucleus of the atom

[darce]

1. Energy and matter flow into and out of the system. (Explanation: by definition of open system)
2. Oxygen (Explanation: combustion usually involves carbon and oxygen)
3. Neither energy nor matter are exchanged with the surroundings. (Explanation: by definition of isolated system)
4. the rate of particle movement decreases (Explanation: KE= 1/2 mv^2. Kinetic energy is the measurement of heat aka temp. v is velocity. KE is directly proportional to V)
5. the individual work of JJ Thompson, creator of the Plum-Pudding model
6. The model gradually changed as new scientific data was gathered.
7. Energy is neither created nor destroyed; it is transformed and transferred. (Explanation: by definition)
8. Energy enters and exits the system, matter does not.
9. the addition of a small, dense nucleus to the center of the atom