The enthalpy change : -196.2 kJ/mol
<h3>Further explanation </h3>
The change in enthalpy in the formation of 1 mole of the elements is called enthalpy of formation
The enthalpy of formation measured in standard conditions (25 ° C, 1 atm) is called the standard enthalpy of formation (ΔHf °)
(ΔH) can be positive (endothermic = requires heat) or negative (exothermic = releasing heat)
The value of ° H ° can be calculated from the change in enthalpy of standard formation:
∆H ° rxn = ∑n ∆Hf ° (product) - ∑n ∆Hf ° (reactants)
Reaction
2 H₂O₂(l)-→ 2 H₂O(l) + O₂(g)
∆H ° rxn = 2. ∆Hf ° H₂O - 2. ∆Hf °H₂O₂
We are given the following equation:
y = y0 e^-0.0001216 t
where y = 1/5 y0, y0 is the original amount
So solving for time t:
1/5 y0= y0 e^-0.0001216 t
t = 13,235.51 years
So the human died about 13235.5 years ago
Hey there!
To calculate the percent by mass of the Ca(NO₃)₂ we need to find the total mass first by adding.
896.92 + 22.63 = 919.55
In total, the solution is 919.55 grams.
To find the percent of Ca(NO₃)₂ in the solution, divide the mass of Ca(NO₃)₂ by the total mass and multiply by 100.
22.63 ÷ 919.55 = 0.0246
0.0246 x 100 = 2.46
Ca(NO₃)₂ makes up 2.46% of the solution.
Hope this helps!
Einstein’s Theory of Relativity was built on the research and ideas of other scientists. The Theory of Relativity proposes that the speed of light is aconstant. The statement that explains why this is considered to be a scientific theory is that the majority of the scientific community voted on this theory over other possible explanations.
The correct answer would be D: Physical properties can be observed without changing the identity of a substance
