Explanation:
Things that float=paper,plastic bottle,rubber, polythene bag, balloon
Things that sinks =needle,stone,spoon,pen,soap
Answer:
There are 9.8 ×1021. formula units in 10,005.8gCaO
Answer: - 5.00 kJ
Explanation:
1) The heat evolved during the reation is proportional to the number of moles dissolved.
2) Proportionality = ratio is constant
<span>3) δh°soln of HNO3 is –33.3 kJ/mol => ratio 1
-33.3 kJ
ratio 1 = ---------------------
1 mol HNO3
4) ratio 2
x
--------------
0.150 mol
</span>
5) proportion
ratio 1 = ratio 2
x -33.3 kJ
--------------- = -------------- => x = 0.150 mol * (-33.3kJ) / 1 mol = - 4.995 kJ ≈
0.150 mol 1 mol
≈ - 5.00 kJ
Answer:
4:5
Explanation:
Let x represent the fraction of the mix that is hot water. Then the temperature of the mix is ...
60x +15(1-x) = 40·1
45x = 25 . . . . . . . . . subtract 15
x = 25/45 = 5/9 . . . divide by the coefficient of x
This is the fraction that is hot water, so the fraction that is cold water is ...
1-5/9 = 4/9
The ratio of cold to hot is ...
cold : hot = (4/9) : (5/9) = 4 : 5
_____
<em>Additional comments</em>
The problem assumes that the energy contained in a given mass of water is proportional to its temperature. That is almost true, sufficiently so that we can reasonably use that approximation.
If heat loss is figured into the problem, then additional information is needed regarding the energy content of water at temperatures in the range of interest. That is not provided by this problem statement, so we have ignored the heat loss.
