Answer:
B. 214.02
Explanation:
1 mol of water weighs 18.015 gm and contains 6.023 × 10²³ molecules
From question, We have 7.15 × 10²⁴ molecules
Dividing we get (7.15 × 10 ²⁴) ÷ ( 6.023 × 10²³) = 11.871 molecules
Now, Weight of water = 11.871 × 18.015 = 213.85 which is nearer to option B
Answer:
0.641 moles of ethane
Explanation:
Based on the equation:
C2H6(g) + 7/2O2(g) → 2CO2(g) + 3H2O(l)
We can determine ΔH of reaction using Hess's law. For this equation:
<em>Hess's law: ΔH products - ΔH reactants</em>
ΔH = {2ΔHCO2 + 3ΔHH2O} - {ΔHC2H6}
<em>Pure monoatomic substances have a ΔH = 0kJ/mol; ΔHO2 = 0kJ/mol</em>
<em />
ΔH = {2*-393.5kJ/mol + 3*-285.8kJ/mol} - {-84.7kJ/mol}
ΔH = -1559.7kJ/mol
That means when 1 mole of ethane is in combustion there are released 1559.7kJ of heat. To produce 1.00x10³kJ there are needed:
1.00x10³kJ * (1mole ethane / 1559.7kJ) =
<h3>0.641 moles of ethane</h3>
Answer:
The correct answer is B.
Explanation:
Heterogeneous equilibrium is that in which reagents and products are present in more than one phase.
When the reaction is carried out in a closed container, three equilibrium phases are present: solid magnesium oxide, solid magnesium sulfate and gaseous sulfur trioxide.
Hence, the equilibrium contant is given by:
![K=\frac{[MgSO_4]}{[MgO][SO_3]} =\frac{1}{[SO_3]}](https://tex.z-dn.net/?f=K%3D%5Cfrac%7B%5BMgSO_4%5D%7D%7B%5BMgO%5D%5BSO_3%5D%7D%20%3D%5Cfrac%7B1%7D%7B%5BSO_3%5D%7D)
The concentrations in the equilibrium equation are the relationships of the real concentrations between the concentrations in the standard state. Since the standard state of a pure solid is the pure solid itself, the ratio of concentrations for a pure solid is equal to one.
Now, we analyse each statement:
I) As the reaction is endothermic (ΔH>0), increasing the temperature shifts the balance to the right because excess heat will be used to form more products.
II) Increasing the volume will decrease the concentration of SO₃, so Q>K and then this shifts the balance to the left.
III) As it is a heterogeneous balance, adding MgO will not affect the balance.
IV) Removing SO3 will decrease its concentration and therefore the reaction equilibrium will shift to the left.
Answer:
Number of moles is 3.0moles
Explanation:
Volume (v) = 67.2L
Pressure at STP = 1atm
Temperature at STP = 273.15K
R = 0.082J/mol.K
Number of moles (n) = ?
From ideal gas equation,
PV = nRT
P = pressure
V = volume of the gas
n = number of moles
R = ideal gas constant
T = temperature of the gas
PV = nRT
solving for n,
n = PV / RT
n = (1.0 * 67.2) / (0.082 * 273.15)
n = 67.2 / 22.398
n = 3.0 moles
The number of moles present is 3.0
Answer:
different elements have different numbers of neutrons.