| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 2.97 |
| Score | 0% | 59% |
Which of the following substances gives up negatively charged hydroxide ions (OH-) when dissolved in water?
acid |
|
base |
|
ion |
|
hydrogen |
An acid is a substance that gives up positively charged hydrogen ions (H+) when dissolved in water. A base (alkaline) gives up negatively charged hydroxide ions (OH-) when dissolved in water. pH is a scale that measures of how basic or acidic a solution is. Numbered from 0 to 14, solutions with a pH of 7 are neutral, less than 7 are acidic, more than 7 are alkaline.
Which of the following describes the Earth's outer core?
solid |
|
makes up most of the Earth's volume |
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primarily solid |
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liquid |
The Earth's core is divided into the liquid outer core (1,430 miles or 2,300 km radius) and the solid inner core (745 miles or 1,200 km radius).
50°F is how many °C?
122 |
|
-10 |
|
58 |
|
10 |
The formula to convert from F° to C° is:
\(C° = {5 \over 9} (F° - 32)\)
plugging in our values gives:
\(C° = {5 \over 9} (50 - 32)\)
\(C° = {5 \over 9} (18)\)
\(C° = {90 \over 9}\)
\(C° = 10\)
The gravitational interaction of Earth and the Moon is responsible for which of these?
tides |
|
the northern lights |
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seasons |
|
day and night cycle |
Tides are caused by the gravitational interaction of Earth and the Moon.
Which of the following is not true of light waves?
are electromagnetic waves |
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travel faster than sound waves |
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can travel through a vacuum |
|
are mechanical waves |
Unlike mechanical sound waves that require a physical medium for propagation, light waves are electromagnetic and can travel through empty space. Light waves are also much faster, travelling at 186,000 m/s vs. 343 m/s for sound waves.