Answer:
C
Explanation:
It is C because the change is inversible, that means that it is a chemical change.
Answer:
pH of soltion will be 5.69
Explanation:
The pH of the solution will be due to excessive acid left and the salt formed. Thus, it will form a buffer solution.
The pH of buffer solution is calculated from Henderson Hassalbalch's equation, which is:
![pH=pKa+log(\frac{[salt]}{[acid]} )](https://tex.z-dn.net/?f=pH%3DpKa%2Blog%28%5Cfrac%7B%5Bsalt%5D%7D%7B%5Bacid%5D%7D%20%29)
The moles of acid taken :
The moles of base taken:
The moles of acid left after reaction :
The moles of salt formed = 4.5mmol
Putting values in equation
![pH=pKa+log(\frac{[salt]}{[acid]} )=4.74+log(\frac{4.5}{0.5})=5.69](https://tex.z-dn.net/?f=pH%3DpKa%2Blog%28%5Cfrac%7B%5Bsalt%5D%7D%7B%5Bacid%5D%7D%20%29%3D4.74%2Blog%28%5Cfrac%7B4.5%7D%7B0.5%7D%29%3D5.69)
Answer:
The density remains the same
Explanation:
The density remains the same because cutting the object in half will divide the mass & volume by the same amount. The density cant be changed no matter what happens to it.
Answer: metallic solid
Explanation:
Copper is a metallic crystalline solid. A metallic solid is an element that can withstand high temperatures and conduct electricity.
Answer: 1.2044 × 10^24
Explanation:
1 mole of calcium is 40 gram
Based on Avogadro's law:
1 mole of any substance has 6.02 x 10^23 atoms, also 1 mole of calcium is 40gram
So, 1 mole of calcium = 6.02 x 10^23 atoms
Also, 1 mole of calcium is 40gram
40 grams of calcium = 6.02 x 10^23 atoms
80.156 grams of calcium = Z atoms
To get the value of Z, cross multiply:
Z atoms x 40 grams = 6.02 x 10^23 atoms x 80.156 grams
40Z = 482.54 x 10^23
Z = (482.54 x 10^23/40)
Z = 12.06 x 10^23
Put result in standard form
Z = 1.206 x 10^24 atoms
Thus, 1.206 x 10^24 atoms of Ca are present in 80.156 grams of Ca
