Well first of all, I think the students may have been correct.
If they didn't use distilled water, and if it wasn't exactly at
standard temperature, then the mass of 25.0 mL could
very well be 25.4 grams. We don't know that there was
any 'error' in their measurement at all.
But the question says there was, so we'll do the math:
The 'error' was (25.4 - 25.0) = +0.4 gram
As a fraction of the 'real' value, the error was
+0.4 / 25.0 = +0.016 .
To change a decimal to a percent, move the
decimal point two places that way ===> .
+ 0.016 = +1.6 % .
Their measurement was 1.6% too high.
Let's not call it an 'error'. Let's just call it a 'discrepancy'
between the measured value and the 'accepted' value. OK ?
If you have a lump of solid at its melting point ... like ice at 32°F ...
you have to put a certain amount of heat into it just to change it
to water at 32°F. That amount of heat, that's used just to change
a solid lump into liquid without changing its temperature, is called
the heat of fusion for that substance.
The number is different for every substance.
For water, it takes 336 joules of heat to melt 1 gram of ice
into 1 gram of water, all at 32°F (0°C).
That's an enormous latent heat of fusion ... more than almost any
other known substance. That's why ice is such a good choice
when you need something to put in your drink to cool it down.
Ice absorbs a huge amount of heat before it melts and the drink
gets watered down.
Answer:
2 they detect radio waves
