the balanced chemical equation for decomposition of HgO is as follows
2HgO --> 2Hg + O₂
stoichiometry of HgO to O₂ is 2:1
number of HgO moles heated are - 3.00 g / 216.59 g/mol = 0.0139 mol
according to stoichiometry of reaction -
number of O₂ moles formed = 0.0139 mol/ 2 = 0.00695 mol
mass of O₂ to be formed - 0.00695 mol x 32.00 g/mol = 0.2224 g
but the actual yield = 0.195 g
percent yield = actual yield / theoretical yield x 100 %
percent yield = 0.195 g / 0.2224 g x 100 % = 87.7 %
answer is 87.7 %
Answer:
c) 22
Explanation:
Let's consider the following balanced equation.
N₂(g) + 3 H₂(g) ----> 2 NH₃(l)
According to the balanced equation, 34.0 g of NH₃ are produced by 1 mol of N₂. For 170 g of NH₃:
According to the balanced equation, 34.0 g of NH₃ are produced by 3 moles of H₂. For 170 g of NH₃:
The total gaseous moles before the reaction were 5.00 mol + 15.0 mol = 20.0 mol.
We can calculate the pressure (P) using the ideal gas equation.
P.V = n.R.T
where
V is the volume (50.0 L)
n is the number of moles (20.0 mol)
R is the ideal gas constant (0.08206atm.L/mol.K)
T is the absolute temperature (400.0 + 273.15 = 673.2K)
First, we are using the ideal gas law to get n the number of moles:
PV = nRT
when P is the pressure = 748 mmHg/760 = 0.984 atm
V is the volume = 4 L
R is ideal gas constant = 0.0821
T is the temperature in Kelvin = 300 K
∴ n = 0.984atm*4L/0.0821*300
= 0.1598 moles
when the concentration = moles * (1000g / mass)
= 0.1598 * (1000g / 58 g )
= 2.755 M
when the freezing point = 5.5 °C
and Kf = - 5.12 °C/m
∴ the freezing point for the solution = 5.5 °C + (Kf*m)
= 5.5 °C - (5.12°C/m * 2.755m)
= -8.6 °C
Answer:
Explanation:
25 % ( m / v ) mannitol solution means 25 gram in 100 cc of water
25 gram in 100 mL of water
grams of mannitol in 30 mL = 25 x 30 / 100
= 7.5 grams .
The mass number goes on top, and the atomic number goes on bottom.
Therefore, the answer is C:
40
K
19
