Answer:
![\large \boxed{\text{D. 23.34 min}}](https://tex.z-dn.net/?f=%5Clarge%20%5Cboxed%7B%5Ctext%7BD.%2023.34%20min%7D%7D)
Explanation:
1. Find the order of reaction
Use information from the graph to find the order.
If a plot of ln[A] vs time is linear, the reaction is first order and the slope = -k.
2. Find the half-life
![k = \dfrac{\ln2}{ t_{\frac{1}{2}}}\\\\k = \text{-slope} = -(-2.97 \times 10^{-2} \text{ min}^{-1}) =2.97 \times 10^{-2} \text{ min}^{-1} \\ t_{\frac{1}{2}} =\dfrac{\ln 2}{k} = \dfrac{\ln 2}{2.97 \times 10^{-2}\text{ min}^{-1}} =\textbf{23.34 min}\\\\\text{The half-life is $\large \boxed{\textbf{23.34 min}}$}](https://tex.z-dn.net/?f=k%20%3D%20%5Cdfrac%7B%5Cln2%7D%7B%20t_%7B%5Cfrac%7B1%7D%7B2%7D%7D%7D%5C%5C%5C%5Ck%20%3D%20%5Ctext%7B-slope%7D%20%3D%20-%28-2.97%20%5Ctimes%2010%5E%7B-2%7D%20%5Ctext%7B%20min%7D%5E%7B-1%7D%29%20%3D2.97%20%5Ctimes%2010%5E%7B-2%7D%20%5Ctext%7B%20min%7D%5E%7B-1%7D%20%5C%5C%20t_%7B%5Cfrac%7B1%7D%7B2%7D%7D%20%3D%5Cdfrac%7B%5Cln%202%7D%7Bk%7D%20%3D%20%5Cdfrac%7B%5Cln%202%7D%7B2.97%20%5Ctimes%2010%5E%7B-2%7D%5Ctext%7B%20min%7D%5E%7B-1%7D%7D%20%3D%5Ctextbf%7B23.34%20min%7D%5C%5C%5C%5C%5Ctext%7BThe%20half-life%20is%20%24%5Clarge%20%5Cboxed%7B%5Ctextbf%7B23.34%20min%7D%7D%24%7D)
Answer:- 448 mL of hydrogen gas are formed.
Solution:- It asks to calculate the volume of hydrogen gas formed in milliliters at STP when 0.020 moles of magnesium reacts with excess HCl acid. The balanced equation is:
![Mg+2HCl\rightarrow MgCl_2+H_2(g)](https://tex.z-dn.net/?f=Mg%2B2HCl%5Crightarrow%20MgCl_2%2BH_2%28g%29)
There is 1:1 mol ratio between Mg and hydrogen gas. So, the moles of hydrogen gas is also equals to the moles of Mg reacted.
moles of Hydrogen gas formed = 0.020 mol
At STP, volume of 1 mol of the gas is 22.4 L. We need to calculate the volume of 0.02 moles of hydrogen gas.
![0.02mol(\frac{22.4L}{1mol})](https://tex.z-dn.net/?f=0.02mol%28%5Cfrac%7B22.4L%7D%7B1mol%7D%29)
= 0.448 L
They want answer in mL. So, let's convert L to mL using the conversion formula, 1L = 1000mL
![0.448L(\frac{1000mL}{1L})](https://tex.z-dn.net/?f=0.448L%28%5Cfrac%7B1000mL%7D%7B1L%7D%29)
= 448 mL
So, 0.020 moles of magnesium would produce 448 mL of hydrogen gas at STP on reacting with excess of HCl acid.
Answer:
Explanation:
Oppositely charged particles attract each other, while like particles repel one another. Electrons are kept in the orbit around the nucleus by the electromagnetic force, because the nucleus in the center of the atom is positively charged and attracts the negatively charged electrons.