The temperature rises from 25.00°c to 29.00°c in a bomb calorimeter when 3.50 g of sucrose undergoes combustion in a bomb calorimeter. Calculate δerxn for the combustion of sucrose in kj/mol sucrose. The heat capacity of the calorimeter is 4.90 kj/°c. The molar mass of sugar is 342.3 g/mol.

Energy change for the combustion reaction = -1921.6 kJ/mol

Explanation:

Step 1: Data given

Initial temperature of calorimeter T1 = 25°C

Final temperature T2 = 29°C

Heat capacity of calorimeter c = 4.90 kJ/°C

Mass of sucrose  = 3.5 g

Molar mass of sucrose = 342.3 g/mol

Step 2: Calculate the heat gained

The change in temperature of calorimeter = T2 -T1 = 29.0 °C- 25.0 °C = 4.0°C

Heat gained by the calorimeter when the temperature changes by 4°C

= 4°C * 4.90 kJ/ 1 C = 19. 6 kJ

Step 3: Calculate moles of sucrose

moles sucrose = mass sucrose / molar mass sucrose

Moles sucrose = 3.50 grams / 342.3 g/mol

Moles sucrose = 0.0102 moles

Step 4: Calculate energy change for the combustion reaction

Energy change for the combustion reaction = -19.6 kJ/0.0102 moles  = -1921.6 kJ/mol

explanation:

metals have excess of electrons whereas non-metals have deficiency of electrons. thus, in order to gain stability metals easily donate their electrons to the non-metals.

for example, electronic configuration of sodium is and electronic configuration of phosphorous is .

when a phosphorous atom and sodium atom combine together then sodium will donate is extra one electron to the phosphorous atom. as a result there will be formation of ionic bond between sodium and phosphorous.

the reaction will be as follows.

there, are three sodium sodium atoms and each of them will donate its one extra electron to phosphorous atom. thus, the sub-shell of phosphorous gets completely filled.  

thus, we can conclude that electrons are transferred from atoms of sodium to atoms of phosphorous. this transfer makes the sodium atoms donate one electron and the phosphorous atoms to gain one electron. as a result, the sodium and phosphorus atoms strongly attract each other.

number of molecules / avogadro's number * molecule molecular = mass

explanation:

we define a gram-molecular weight as the mass of one mole of any element or compound. a mole contains avogadro's number of units (molecules) –  

6.022

x

10

23

. so, dividing the number of molecules by avogadro's number gives us the number of moles. multiplying that by the molecular weight gives us the mass. from the periodic table we find the gram-molecular weight of u to be238 and of f to be19. so,  

u

f

6

will have a gram-molecular weight of 352g.