The answer is the 3rd one
A. phase changing. Physical change is any change in matter that involves the substance going from one physical state to another, and phase change is most commonly used to describe transitions between solid, liquid and gaseous states of matter.
Preparing 15 mg/gl working standard solution from a 20 mg/dl stock solution will require the application of the dilution principle.
Recalling the principle:
initial volume x initial molarity = final volume x final molarity
Since we were not given any volume to work with, we can as well just take an arbitrary volume to be prepared. Let's assume that the stock solution is 10 mL and we want to prepare 15 mg/gl from it:
Applying the dilution principle:
10 x 20 = final volume x 15
final volume = 200/15
= 13.33 mL
This means that in order to prepare 13.33 mL, 15 mg/l working standard solution from 10 ml, 20 mg/dl stock solution, 3.33 mL of the diluent must be added to the stock solution.
More on dilution principle can be found here: brainly.com/question/11493179
Giant covalent substances have many atoms joined together by covalent bonds. Diamond, graphite and graphene are forms of carbon with different giant covalent structures.
Giant molecular are structure such as graphite or diamond. All bonds are through covalent. They have the same bond throughout the structure without changing.
Answer:
2 unpaired electrons
Explanation:
Carbon's bonding state electron configuration is 1s2 2s1 2s1 2p1 2p1. So, there are 4 unpaired electrons in the orbitals of carbon in bonding state.
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