Answer:
37 mmol of acetate need to add to this solution.
Explanation:
Acetic acid is an weak acid. According to Henderson-Hasselbalch equation for a buffer consist of weak acid (acetic acid) and its conjugate base (acetate)-
![pH=pK_{a}(acetic acid)+log[\frac{mmol of CH_{3}COO^{-}}{mmol of CH_{3}COOH }]](https://tex.z-dn.net/?f=pH%3DpK_%7Ba%7D%28acetic%20acid%29%2Blog%5B%5Cfrac%7Bmmol%20of%20CH_%7B3%7DCOO%5E%7B-%7D%7D%7Bmmol%20of%20CH_%7B3%7DCOOH%20%7D%5D)
Here pH is 5.31, 
(acetic acid) is 4.74 and number of mmol of acetic acid is 10 mmol.
Plug in all the values in the above equation:
![5.31=4.74+log[\frac{mmol of CH_{3}COO^{-}}{10}]](https://tex.z-dn.net/?f=5.31%3D4.74%2Blog%5B%5Cfrac%7Bmmol%20of%20CH_%7B3%7DCOO%5E%7B-%7D%7D%7B10%7D%5D)
or, mmol of 
= 37
So 37 mmol of acetate need to add to this solution.
a. Processes: - Is a series of steps that manipulate data b. Data flows: - Describes the data and the information elements passing between external entities, processes and data stores c. Data stores: - A place to keep data for later use d. External entities:- The original source of data or the receiver of information
526 L O2 x 1 mol O2 / 22.4 L = 23.5 mol O2
Explanation:
A chemical reaction is defined as the reaction in which bonds between the reactants either break or form which leads to the formation of a new substance.
For example, 
So, when we drop a sodium metal into water then it produces a frizzing sound which shows the metal is reacting with water.
We know that when two aqueous solutions chemically react with each other then it may lead to the formation of an insoluble substance which is known as precipitate.
This means that formation of a precipitate is also a chemical reaction.
Thus, we can conclude that following are the statements which show evidence for a chemical reaction.
- Dropping sodium metal into water produces fizzing.
- Mixing two aqueous solutions produces a precipitate.
Answer:
The metal cube lattice is made of only one kind of atom.
Explanation:
As we know that metallic crystals are made up of only one kind of element. A metal crystal is actually a huge sea of positive charges embedded in the layers of negative charges (electrons). The whole crystal is made up of same kind of atoms, e.g crystals of gold, crystals of iron.
If we talk about structure of metallic crystal, it can be body centered cubic, simple cubic, hexagonal or close cubic packing.
Now, coming towards the ionic crystals, we know that they are basically the crystals of ionic compounds like sodium chloride or cesium chloride. These crystals are formed due to ionic bonding between two or more than two kinds of elements/atoms. It is not possible for an ionic crystal to be composed of only one kind of atom. As far as structure is concerned, they can have different structure based on bonding between atoms in an ionic compound, e.g NaCl has octahedral geometry.
Therefore, it is very evident that best option is A.
