The Nuclear Model-1909. Ernest Rutherford's great contribution to atomic theory was to show what happens to an element during radioactive decay. This enabled him to construct the first nuclear model of the atom, a cornerstone of present-day physics The Nuclear Model-1909.
The balanced equation
for the reaction is:
6 HNCO(l) →
C3N3(NH2)3(l) + 3 CO2(g)
Convert amount of urea
from kg to moles
Molar Mass of urea = 60.06
g/mol so, 113 kg urea contains
113 kg / 60.06 = 1.88
mol urea
From balanced equation 6
moles of urea yields only 1 melamine, so divide the moles of urea by 6.
1.88 / 6 = 0.313 kmol
melamine
Now multiply 0.313 with
molar mass of melamine that is 126 g/mol
126 x 0.313 = 39.438 kg
Yield of overall
reaction is 73% so multiply 39.438 with 0.73
<span>39.438 x 0.73 = 28.799
kg is the answer</span>
Answer:
*moles = molarity(M=moles/L) * volume (L)
so, you have 4.25 * 0.735 moles
*NH3
* M=n/v
*To determine the number of significant figures in a number use the following 3 rules: Non-zero digits are always significant. Any zeros between two significant digits are significant. A final zero or trailing zeros in the decimal portion ONLY are significant.
Answer:
1. Ice at 0 degrees C.
2. N₂ at STP.
3. N₂ at STP.
4. Water vapor at 150 degrees C and 1 atm.
Explanation:
First, we need to remember that entropy (S) is a <em>measure of how spread out or dispersed the energy of a system is among the different possible ways that system can contain energy</em>. The greater the dispersal, the greater is the entropy.
When the temperature is increased, the energies associated with all types of molecular motion increase. Consequently, the entropy of a system always increases with increasing temperature.
With this in mind, we consider the pairs:
1. Since the ice at 0ºC has a greater temperature than the ice at -40 ºC, the first has the higher entropy.
2. The N₂ at STP (that is, 1 atm and 25 ºC) has higher entropy than N₂ at 0ºC and 10 atm because it has a higher temperature and less pressure, which allows a greater dispersal of energy by the molecules of the gas.
3. The N₂ at STP has a higher entropy since it has a higher temperature than N₂ at 0ºC, even though it the first has a lower volume (24,4 L vs. 50 L).
4. The water vapor at 150 ºC and 1 atm have a higher temperature and a lower pressure. This means that its molecules will have an increased molecular motion than the molecules of water vapor at a lower temperature and higher pressure. Therefore, the first has the highest entropy.
First calculate mass of sodium hydrogen phosphate (Na₂HPO₄) needed for solution:
n(Na₂HPO₄) = V(Na₂HPO₄) · c(Na₂HPO₄)
n(Na₂HPO₄) = 0,3 dm³ · 0,2 mol/dm³
n(Na₂HPO₄) = 0,06 mol
m(Na₂HPO₄) = 0,06 mol · 142 g/mol
m(Na₂HPO₄) = 8,52 g.
Measure that mass on scale using spoon and beaker. Than dissolve salt in beaker with distilled <span>water and pour that solution in volumetric flask (size 300 mL), pour </span>distilled water to graduation<span> mark.</span>
