Answer:
A. Compounds
Explanation:
Firstly, don't let the word "pure" confuse you; this is pretty much irrelevant to the question.
The key to answering this question lies in "substance" and "more than one type of element chemically bonded."
Something you ought to memorize is that a substance is either an element or compound. Therefore, you can eliminate choices B./C.
Next, use the part of the definition that says "more than one type of element chemically bonded" to conclude that it's a compound. Not only is this the definition of a compound, but the fact that is says <em>more than one type of element</em> should automatically tell you that it is different from just a regular element (Choice D.).
Answer: The density of the object will be 
Explanation:
Density is defined as the mass contained per unit volume.

Given : Mass of object = 19.6 grams
Volume of object= 
Putting in the values we get:

Thus density of the object will be 
Rechargeable batteries use a reversible reaction medium to convert electrical current to a form of chemical energy which can be stored for future use.
<h3>
What is a rechargeable battery?</h3>
A rechargeable battery is a type of battery that can be charged many times by passing electric current through the cells in a reversible reaction.
<h3>How does recahargeable battery store energy?</h3>
When electrical energy from an outside source is applied to a secondary cell (reachargeable battery), the negative to positive electron flow that occurs during discharge is reversed, and the cell's charge is restored. This process is called reversible reaction.
Thus, rechargeable batteries use a reversible reaction medium to convert electrical current to a form of chemical energy which can be stored for future use.
Learn more about reversible reaction here: brainly.com/question/11412193
Answer:
A
Explanation:
Nitrogen is an atom made up of 7 electrons.
To draw the orbital energy level diagram, let us write the orbital notation of the atom;
7 electrons of Nitrogen:
1s² 2s² 2p³
So,
The orbital notation diagram is :
1s² 2s² 2p³
↑↓ ↑↓ ↑↑↑
Answer:
0.200 m K3PO3
Explanation:
Let us remember that the freezing point depression is obtained from the formula;
ΔTf = Kf m i
Where;
Kf = freezing point constant
m = molality
i = Van't Hoff factor
The Van't Hoff factor has to do with the number of particles in solution. Let us consider the Van't Hoff factor for each specie.
0.200 m HOCH2CH2OH - 1
0.200 m Ba(NO3)2 - 3
0.200 m K3PO3 - 4
0.200 m Ca(CIO4)2 - 3
Hence, 0.200 m K3PO3 has the greatest van't Hoff factor and consequently the greatest freezing point depression.