The powder catches fire. The rest of the choices pertains to physical changes on the powder. When the powder catches fire a chemical change happens. For example, if the powder is organic, carbon dioxide and water will result during the combustion.
Answer:
(a) from the anode to the cathode through the external circuit
Explanation:
In an electrochemical cell, there are two half cells; the oxidation half cell and reduction half cell. Oxidation typically refers to loss of electrons and reduction refers to gain of electrons.
Electrons always flow from the anode to the cathode or from the oxidation half cell to the reduction half cell.
The electrical circuit in an electrochemical cell confirms the flow of electron. Usually a light bulb is attached. The correct option is;
(a) from the anode to the cathode through the external circuit
<u>Explanation:</u>
Molecular formula is the chemical formula which depicts the actual number of atoms of each element present in the compound.
Empirical formula is the simplest chemical formula which depicts the whole number of atoms of each element present in the compound.
In both the formulas, the nature of atoms remains the same but the number differs.
For Example: The molecular formula of oxalic acid is 
but the empirical formula of oxalic acid is 
To calculate the molecular formula, we need to find the valency which is multiplied by each element to get the molecular formula.
The equation used to calculate the valency is:
The empirical mass can be calculated from empirical formula and molar mass must be known.
Answer:
The potential difference is considered as the change in terms of voltage or Del V. It is measured in terms of voltage so that statement got the name voltage change between point A & B is 1. It means that I joule of work is carried out for moving the 1 coulomb of charge from the point A to B.
((12g/mol)/(28.01g/mol))*100% = 42.84%
