How much heat is required to raise the temperature from 26 degree centigrade to 50 degree centigrade for 100 gr lead?

1 Answer
zhirou
Apr 4, 2018

#"400 J"#, or #"90 cal"#.

Explanation:

To solve this problem, we'll need to use this equation:

#q=mCDeltaT#

Where #q# is heat, #m# is mass in grams, #C# is specific heat, and #DeltaT# is change in temperature.

The question gives us #m#, which is #"100 g"#.
We can also use the initial and final temperatures given in the question, #"26°C"# and #"50°C"#, to find #DeltaT#. #DeltaT# is #50-26="24°C"#.

The specific heat of lead, from a quick search, is #"0.160 J/g°C"#.

So, we can just plug these into the equation and solve for #q#:

#q=mCDeltaT#
#q="100 g" xx "0.160 J/g°C" xx "24°C"#
#q="384 J"# or #"91.78 cal"#

Since the lowest number of significant figures in the question is #1#, our answer needs to also have #1# significant figure.
That would make it #"400 J"#, or #"90 cal"#.

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