Answer:
A. to determine the efficiency of the reaction
Explanation:
- Percentage is the ratio of the actual yield to theoretical yield as a percentage. It is calculated by dividing the actual yield by theoretical yield then multiplying by 100%.
- Calculation of percentage yield is important as it helps in the determination of efficiency of a reaction. For example in most industries for the purpose of making the most product with the least waste.
- Additionally, calculating the percentage yield helps in determining other products that may be formed during the reactions.
To determine the molar mass of the unknown gas, we use Graham's Law of Effusion where it relates the effusion rates of two gases with their molar masses. It is expressed as r1/r2 = √M2/M1. We calculate as follows:
Let 1 = argon gas 2 = unknown gas
r2 = 0.91r1r1/r2 = 1/0.91
1/0.91 = √M2/M1 = √M2/40M2 = 48.30 g/mol
8 valence electrons means that the element is stable. When we hear stable, we know the group to look at! Noble gases all have 8 valence electrons making them stable and have a full octet.
Here are some:-
Krypton
Argon
Neon
Answer:
Covalent
Explanation:
A molecule of C₂H₅OH has C-C, C-H, C-O, and O-H bonds.
A bond between A and B will be ionic if the difference between their electronegativities (ΔEN) is greater than 1.6.

No bond has a large enough ΔEN to be ionic.
C₂H₅OH is a covalent molecule.