Answer:
Both metals and non metals.
Explanation:
The correct formula of baking soda is NaHCO₃,
An element is considered to be metal if it is able to give electron easily due to very low ionization energy.
A non metal is ready to accept electron easily due to high electron affinity.
In sodium bicarbonate :
Na: Sodium : metal
H : Hydrogen: non metal (although placed with first group, alkali metals, in the periodic table as it readily loses electron like metals)
C: Carbon: Non metal
O : Oxygen : Non metal.
So the compound contains both metals and non metals.
In a solution of KBr and water; KBr is the solute and water is the solvent;
Therefore; to achieve 3% by mass; it means we are going to have 3% of the mass being the solute and the other 97 % being the solvent.
Thus; KBr (solute) = 3/100 × 300 (total mass) = 9 g
Hence; the appropriate masses will be; 9.00 g of KBr and 291 g of water.
As a base is added to an acidic solution, the H+ ions in solution that make it acidic are slowly neutralized into water (via OH-, the base). As these ions are converted into water the concentration of them decreases, so the pH decreases, as they are directly related.
Hope this helps!
