The empirical formula is
.
<u>Explanation:</u>
Putrescine has the elements like Carbon, Nitrogen and Hydrogen present in them. So in order to determine the empirical formula, we first have to find the number of moles present in the putrescine. As the percentage of C, H and N present in the chemical is given as 54.50%, 13.73% and 31.77%, we assume that 100 g of Putrescine is taken as sample.
Then the mass of C, H and N present in Putrescine will be 54.50 g, 13.73 g and 31.77 g. We know that the molar mass of C is 12 g/mol, H is 1 g/mol and N is 14 g/mol. So divide the mass with the molar mass of the respective elements to determine the number of moles of these elements present in the sample.
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Similarly, the number of moles of H and N present is determined.


Then the empirical formula can be determined by dividing the number of moles of all elements with the least number of moles that is 2.27.

So, the empirical formula is
.
<span>294400 cal
The heating of the water will have 3 phases
1. Melting of the ice, the temperature will remain constant at 0 degrees C
2. Heating of water to boiling, the temperature will rise
3. Boiling of water, temperature will remain constant at 100 degrees C
So, let's see how many cal are needed for each phase.
We start with 320 g of ice and 100 g of liquid, both at 0 degrees C. We can ignore the liquid and focus on the ice only. To convert from the solid to the liquid, we need to add the heat of fusion for each gram. So multiply the amount of ice we have by the heat of fusion.
80 cal/g * 320 g = 25600 cal
Now we have 320 g of ice that's been melted into water and the 100 g of water we started with, resulting in 320 + 100 = 420 g of water at 0 degrees C. We need to heat that water to 100 degrees C
420 * 100 = 42000 cal
Finally, we have 420 g of water at the boiling point. We now need to pump in an additional 540 cal/g to boil it all away.
420 g * 540 cal/g = 226800 cal
So the total number of cal used is
25600 cal + 42000 cal + 226800 cal = 294400 cal</span>
Answer:
an object is a rest upon a table
Uhhh pretty sure B
Happy New Years
Answer:
3.47 mol MnSO4
Explanation:
54.94 + 32.07 + (16 × 4) = 151.01g/mol MnSO4
542.32g / 151.01g/mol = 3.47 mol MnSO4