| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 2.88 |
| Score | 0% | 58% |
Work is measured in:
watts |
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amps |
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horsepower |
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joules or newton-meters |
Work is performed on an object when an applied force causes displacement along the same vector. Measured in joules (J) or newton-meters (Nm), work is calculated by multiplying force times displacement: \(W = \vec{F}\vec{d}\)
Which of the following is not a characteristic of the Sun?
formed 2.6 billion years ago |
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makes up over 99% of the mass of the solar system |
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is composed of hydrogen and helium |
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is a yellow dwarf star |
The Sun is a G-type main-sequence star (G2V) but is informally known as a yellow dwarf star. Composed of 73% hydrogen and 25% helium, the hot plasma that makes up the Sun reaches 9,900°F (5,505°C) at the surface. It formed approximately 4.6 billion years ago and makes up 99.86% of the mass in the solar system.
Which of these is matter than cannot be separated into different types of matter by ordinary chemical methods?
element |
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compound |
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molecule |
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atom |
An element is matter than cannot be separated into different types of matter by ordinary chemical methods.
Elements in the same group in the Periodic Table of the Elements have the same:
number of electron shells |
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number of electrons in their outer electron shell |
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number of electrons |
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number of atomic mass units |
The columns of the Periodic Table are called groups and all elements in a group have the same number of electrons in their outer electron shell. The group that an element occupies generally determines its chemical properties as the number of outer shell electrons establishes the way it reacts with other elements to form molecules. So, because each element has the same number of electrons in its outer shell, each has similar reactivity.
The transfer of heat by the circulation or movement of the heated parts of a liquid or gas is called:
radiation |
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conduction |
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convection |
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diffusion |
Convection is the transfer of heat by the circulation or movement of the heated parts of a liquid or gas. Examples of heat transfer by convection include water coming to a boil on a stove, ice melting, and steam from a cup of coffee.