Compound is a pure substance where atoms of two or more elements are chemically bonded togather
Answer:
We have to add 9.82 grams of calcium acetate
Explanation:
Step 1: Data given
Molarity of the calcium acetate solution = 0.207 M
Volume = 300 mL = 0.300 L
Molar mass calcium acetate = 158.17 g/mol
Step 2: Calculate moles calcium acetate
Moles calcium acetate = molarity * volume
Moles calcium acetate = 0.207 M * 0.300 L
Moles calcium acetate = 0.0621 moles
Step 3: Calculate mass calcium acetate
Mass calcium acetate = moles * molar mass
Mass calcium acetate = 0.0621 moles * 158.17 g/mol
Mass calcium acetate = 9.82 grams
We have to add 9.82 grams of calcium acetate
Answer:
The pH value of the mixture will be 7.00
Explanation:
Mono and disodium hydrogen phosphate mixture act as a buffer to maintain pH value around 7. Henderson–Hasselbalch equation is used to determine the pH value of a buffer mixture, which is mathematically expressed as,
![pH=pK_{a} + log(\frac{[Base]}{[Acid]})](https://tex.z-dn.net/?f=pH%3DpK_%7Ba%7D%20%2B%20log%28%5Cfrac%7B%5BBase%5D%7D%7B%5BAcid%5D%7D%29)
According to the given conditions, the equation will become as follow
![pH=pK_{a} + log(\frac{[Na_{2}HPO_{4} ]}{[NaH_{2}PO_{4}]})](https://tex.z-dn.net/?f=pH%3DpK_%7Ba%7D%20%2B%20log%28%5Cfrac%7B%5BNa_%7B2%7DHPO_%7B4%7D%20%5D%7D%7B%5BNaH_%7B2%7DPO_%7B4%7D%5D%7D%29)
The base and acid are assigned by observing the pKa values of both the compounds; smaller value means more acidic. NaH₂PO₄ has a pKa value of 6.86, while Na₂HPO₄ has a pKa value of 12.32 (not given, but it's a constant). Another more easy way is to the count the acidic hydrogen in the molecular formula; the compound with more acidic hydrogens will be assigned acidic and vice versa.
Placing all the given data we obtain,


The difference between a mixture and a compound is that a mixture can be easily separated like a salad where you can pick things out and a compounds you are usually not able to undo