Answer: -1835 kJ
Explanation:
According to Hess’s law of constant heat summation, the heat absorbed or evolved in a given chemical equation is the same whether the process occurs in one step or several steps.
According to Hess’s law, the chemical equation can be treated as algebraic expressions and can be added or subtracted to yield the required equation. That means the enthalpy change of the overall reaction is the sum of the enthalpy changes of the intermediate reactions.
(1)
(2)
Net chemical equation:
(3)
Multiplying equation (1) by 4, and reversing we get
(4)
Adding (2) and (4)
Thus enthaply change for the reaction is -1835 kJ.
Answer:
2.5 g mass of Ra-226 will remain after 4800 years.
Explanation:
Given data:
Mass of Ra-226 = 20 g
Sample remain after 4800 years = ?
Solution:
Half life of Ra-226 = 1600 years
Number of half lives passed = T elapsed / half life
Number of half lives passed = 4800 year / 1600 year
Number of half lives passed = 3
At time zero = 20 g
At first half life = 20 g/2 = 10 g
At 2nd half life = 10 g/2 = 5 g
At 3rd half life = 5 g/2 = 2.5 g
Thus, 2.5 g mass of Ra-226 will remain after 4800 years.
Answer:
Pls rate Brainliest and See Explanation
Explanation:
A
2 moles x 6.02 x 10^23 maybe
Answer: Ozone's molecular geometry can be described as bent.
Explanation:
The molecular geometry of the O3 groups has a trigonal planar arrangement.
Here is a quick explanation of the molecular geometry of O3 including a quick description of the O3 bond angles.
Examining the Lewis structure of O3 we can see that there are a pair of unbounded valence electrons at the top of the structure.
Based on VSEPR Theory (Valence Shell Electron Pair Repulsion Theory) these electrons will repel the electron clouds of the two oxygen atoms on the end.
As a result they will be pushed down giving the 03 molecule a bent molecular geometry or shape.
The 03 bond angle will be 116° degrees since it has a Bent molecular geometry
