Answer: C.
Explanation:
The rusting of Clara's bike in which iron changes to rust is a chemical change. In a chemical change: the process is not easily reversible.
Add gelatin and let it boil, then put it in the freezer for 30 minuets
<u>Answer:</u> The number of moles of HI in the solution is 
moles.
<u>Explanation:</u>
We are given:
To calculate the concentration of a substance, we use the equation:
......(1)
- Concentration of ammonia:
![[NH_3]=\frac{0.405mol}{4.90L}=0.083mol/L](https://tex.z-dn.net/?f=%5BNH_3%5D%3D%5Cfrac%7B0.405mol%7D%7B4.90L%7D%3D0.083mol%2FL)
- Concentration of ammonium iodide:
![[NH_4I]=\frac{1.45mol}{4.90L}=0.30mol/L](https://tex.z-dn.net/?f=%5BNH_4I%5D%3D%5Cfrac%7B1.45mol%7D%7B4.90L%7D%3D0.30mol%2FL)
For the given chemical reaction:
The expression of 
for above equation follows:
![K_c=\frac{[HI][NH_3]}{[NH_4I]}](https://tex.z-dn.net/?f=K_c%3D%5Cfrac%7B%5BHI%5D%5BNH_3%5D%7D%7B%5BNH_4I%5D%7D)
Putting values in above equation, we get:
![7.0\times 10^{-5}=\frac{[HI]\times 0.083}{0.30}](https://tex.z-dn.net/?f=7.0%5Ctimes%2010%5E%7B-5%7D%3D%5Cfrac%7B%5BHI%5D%5Ctimes%200.083%7D%7B0.30%7D)
![[HI]=2.53\times 10^{-4}](https://tex.z-dn.net/?f=%5BHI%5D%3D2.53%5Ctimes%2010%5E%7B-4%7D)
Calculating the moles of hydrogen iodide by using equation 1, we get:
Hence, the number of moles of HI in the solution is moles.
Mass number is the sum of protons and neutrons.
Atomic number is the total number of protons present.
Mass number = protons + neutrons
Atomic number = protons present.
From the above equations we can conclude that,
Atomic number= Mass number- neutrons.
Thus we can find out the atomic number by subtracting the number of neutrons from the mass number.
The reaction between 1 mole of NaOH and 1 mole of HCl creates 1 mole of NaCl and 1 mole of water. Meaning that the moles of HCl needs to equal that of NaOH for the solution to be considered equalized. That being said, you first need to find the numbers miles of HCl by multiplying the volume by the molarity to get 0.01 moles HCl. (1Mx0.01L=0.01). That means that you need 0.01 moles of NaOH. I hope that helps. Let me know if anything is unclear.
