How much heat must be removed from 357 g of water at 76.9C in order to cool it down to 18.1C?
1 answer:
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Answer: Option (C) is the correct answer.
Explanation:
A water molecule is made up of two hydrogen atoms and one oxygen atom. Its molecular formula is .
It is known that hydrogen is electropositive in nature whereas oxygen is electronegative in nature. Therefore, oxygen will pull the electron of hydrogen towards itself as a result, there will be formation of partial positive charge on hydrogen and partial negative charge on oxygen atom.
Thus, the water molecule becomes polar. So, we can conclude that water molecule is a polar molecule because water molecules have a positive charge on one end and a negative charge on the other.
Answer:
1090 mmHg
Explanation:
We know that with gases we must use a Kelvin temperatures, so let’s try a plot of pressure against the Kelvin temperature.
We can create a table as follows
<u>t/°C</u> <u>T/K</u> <u>p/mmHg</u>
10 283 726
20 293 750
40 313 800
70 343 880
100 373 960
150 423 ???
I plotted the data and got the graph in the figure below.
It appears that pressure is a linear function of the Kelvin temperature.
y = mx + b
where x is the slope and b is the y-intercept.
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<em>Calculate the slope </em>
I will use the points (275, 700) and (380, 975).
Slope = Δy/Δx = (y₂ - y₁)/(x₂ -x₁) = (975 -700)/(380 – 275) = 275/105 = 2.619
So,
y = 2.619x + b
===============
<em>Calculate the intercept </em>
When x = 275, y = 700.
700 = 2.619 × 275 + b
700 = 720 + b Subtract 720 from each side and transpose.
b = -20
So, the equation of the graph is
y = 2.619x -20
===============
<em>Calculate the pressure</em> at 423 K (150°C)
y = 2.619 × 423 - 20
y = 1110 - 20
y = 1090
At 150 °C, the pressure 1090 mmHg.
The point is approximately at the position of the black dot in the graph.
