Answer is: acid-base indicator or pH indicators.
Acid-base indicators are usually weak acids or bases and they are chemical<span> detectors for hydrogen or hydronium cations.</span>
Example for acid-base indicator is phenolphthalein (molecular formula C₂₀H₁₄O₄). Phenolphthalein is <span>colorless in </span>acidic<span> solutions and pink in </span>basic<span> solutions.
Another example is m</span><span>ethyl orange. It is red colour in acidic solutions and yellow colour in basic solutions.</span>
Answer:
Elements that belong to the <em>same </em><em>GROUP</em><em> </em>of the periodic table have the most similar chemical properties.
Explanation:
A GROUP in the periodic table is a column of elements with the same number of valence electrons. Since electrons are exchanged/shared during a chemical reaction, then elements with similar valence electrons, will react similarly. Thus elements belonging to the <em>same GROUP</em> are most similar in the way they react.
For example: Sodium and Lithium are group 1 elements while fluorine and chlorine are group 17 elements. In a reaction under normal conditions, Sodium and Lithium will both try to give up their single valence electron to form cations. In doing so they will react more similarly. On the other hand, Fluorine and Chlorine who are more inclined to accept a single electron to form cations react less like the group 1 elements and more like each other.
Answer:

Explanation:
Assume you are using 1 L of water.
Then you are washing 4 L of salty oil.
1. Calculate the mass of the salty oil
Assume the oil has a density of 0.86 g/mL.

2. Calculate the mass of salt in the salty oil

3. Calculate the mass of salt in the spent water

4. Mass of salt remaining in washed oil
Mass = 172 g - 150 g = 22 g
5. Concentration of salt in washed oil

Can you be more specific, I think the answer is 7.1506
Yes, free electrons appear in balanced redox reaction equations. However, this is only true for half-reactions. This is because redox reactions primarily involve the transfer of electrons, which are better visualized if explicitly shown in the balanced reactions. In reduction reactions, electrons are placed on the left side of the equation. Oxidation reactions show electrons on the right side of the equation.
Explanation:
A half reaction is either the chemical reaction or reduction reaction part of an oxidoreduction reaction. A half reaction is obtained by considering the amendment in chemical reaction states of individual substances concerned within the oxidoreduction reaction. Half-reactions are usually used as a way of leveling oxidoreduction reactions.The half-reaction on the anode, wherever chemical reaction happens, is Zn(s) = Zn2+ (aq) + (2e-).
The metal loses 2 electrons to create Zn2+. The half-reaction on the cathode wherever reduction happens is Cu2+ (aq) + 2e- = Cu(s).
Here, the copper ions gain electrons and become solid copper.