The answer is the first one sand
Answer:
77%
1.98/2.57= 0.770428016 = 77%
<span>protons - Electrons - Neutrons - Nucleus</span>
Answer:
NiCl₂·4H₂O, its name being nickel (II) chloride tetrahydrate.
Explanation:
The constant mass achieved after heating is the mass of anhydrous nickel (II) chloride, NiCl₂. While the mass lost was water.
- Mass lost = 1.167 g - 0.750 g = 0.417 g
Now we <u>convert 0.750 g of NiCl₂ into moles</u>, using <em>its molar mass</em>:
- 0.750 g NiCl₂ ÷ 129.6 g/mol = 0.0058 mol NiCl₂
Then we <u>convert 0.417 g of H₂O into moles</u>:
- 0.417 g H₂O ÷ 18 g/mol = 0.0231 mol H₂O
With the above information we can calculate that the number of H₂O moles is 4 times higher than the number of NiCl₂ moles.
Meaning that <em>the formula of the hydrate is NiCl₂·4H₂O</em>, its name being nickel (II) chloride tetrahydrate.
Answer:
Explanation:
![[A]_0](https://tex.z-dn.net/?f=%5BA%5D_0)
= Initial concentration = 1.28 M
![[A]](https://tex.z-dn.net/?f=%5BA%5D)
= Final concentration = ![0.17[A]_0](https://tex.z-dn.net/?f=0.17%5BA%5D_0)
k = Rate constant = 0.0632 s
t = Time taken
For first order reaction we have the relation
![kt=\ln\dfrac{[A]_0}{[A]}\\\Rightarrow t=\dfrac{\ln\dfrac{[A]_0}{[A]}}{k}\\\Rightarrow t=\dfrac{\ln\dfrac{[A]_0}{0.17[A]_0}}{0.0632}\\\Rightarrow t=28.037\ \text{s}](https://tex.z-dn.net/?f=kt%3D%5Cln%5Cdfrac%7B%5BA%5D_0%7D%7B%5BA%5D%7D%5C%5C%5CRightarrow%20t%3D%5Cdfrac%7B%5Cln%5Cdfrac%7B%5BA%5D_0%7D%7B%5BA%5D%7D%7D%7Bk%7D%5C%5C%5CRightarrow%20t%3D%5Cdfrac%7B%5Cln%5Cdfrac%7B%5BA%5D_0%7D%7B0.17%5BA%5D_0%7D%7D%7B0.0632%7D%5C%5C%5CRightarrow%20t%3D28.037%5C%20%5Ctext%7Bs%7D)
Time taken to reach the required concentration would be .
