Answer:
-179.06 kJ
Explanation:
Let's consider the following balanced reaction.
HCl(g) + NaOH(s) ⟶ NaCl(s) + H₂O(l)
We can calculate the standard enthalpy change for the reaction (ΔH°r) using the following expression.
ΔH°r = 1 mol × ΔH°f(NaCl(s)) + 1 mol × ΔH°f(H₂O(l)) - 1 mol × ΔH°f(HCl(g)) - 1 mol × ΔH°f(NaOH(s))
ΔH°r = 1 mol × (-411.15 kJ/mol) + 1 mol × (-285.83 kJ/mol) - 1 mol × (-92.31 kJ/mol) - 1 mol × (-425.61 kJ/mol)
ΔH°r = -179.06 kJ
Iron rusts when exposed to air → chemical property
Answer:
b, H2O(s) r H2O(g)
Explanation:
entropy is heat, so increase in heat would mean water gets evaporated or melted, or both in this case. so the only choice above that showed increase in heat is from solid(ice) to gas(water vaper) due to increase in heat in the reaction.
Answer:
- <u>two molecules of ammonia are formed by the reaction of one nitrogen and three hydrogen molecules.</u>
Explanation:
The balanced chemical equation provides information on:
- <u>Reactants</u>: those are the compounds that appear of the left side of the equation, each with its chemical formula.
- <u>Products</u>: those are the compounds that appear on the right side of the equation, again, each with its chemical formula.
- <u>Ratio</u>: the coefficients of each compound (the number to the left of the chemical formula) represent the ratio of the number of molecules that react and are formed.
In the given equation you have:
- Equation: N₂ + 3H₂ → 2NH₃
- The coefficients are 1 for nitrogen, 3 for hydrogen, and 2 for ammonia. Hence, 2 molecules of ammonia are formed by the reaction of 1 molecule of nitrogen and 3 molecules of hydrogen.
To calculate for the volume, we need a relation to relate the number of moles (n), pressure (P), and temperature (T) with volume (V). For simplification, we assume the gas is an ideal gas. So, we use PV=nRT.
PV = nRT where R is the universal gas constant
V = nRT / P
V = 65.5 ( 0.08205 ) (273.15 + 50.30) / 9.15
V = 189.98 L
