Answer:
20.9%
Explanation:
- The percentage by mass of solution is given by dividing the mass of solute in grams by the mass of solution in grams then multiplying it by 100%.
% Mass of solution = mass of solute/mass of solution × 100%
= (27.0 g/ 129.0 g) × 100%
= 20.93%
= 20.9%
The metric system is based on powers of 10 so it is much easier to convert units, often just by moving the decimal point.
Reaction 3 is the double displacement reaction.
Double displacement reaction occurs when the negatively and the positively charged ions of the compounds interchange their position when the new compound in the product is formed.
<h3>Which is a double displacement reaction?</h3>
In the <u>first reaction</u>, the element lead (Pb) is not an ion and no exchange of the cations or the anions occurs hence it is not a double displacement reaction.
In the <u>second reaction</u>, one compound is getting split into two new compounds and is a decomposition reaction.
In the <u>third reaction</u>, 
in 
and 
in 
are anions and cations and exchanges their places to produce two new compounds 
In the <u>fourth reaction</u>, a single compound is generated as the result of the combination reaction and hence, it is not the double displacement reaction.
Therefore, 
is the double displacement reaction.
Learn more about double displacement reaction here:
brainly.com/question/10091171
Supersonic flight over land is typically forbidden to minimize disruption to people on the ground. This meant that until it was over open water, Concorde could not operate at its maximum Mach 2 capability.
<h3>What is Concorde?</h3>
- The Concorde is a tailless aircraft with a drooping nose, an oval delta wing, and a narrow fuselage that allows for seating for 92 to 128 passengers.
- It's improbable that Concorde will ever fly for an airline again in a commercial capacity. The economics of reactivating Concorde and incorporating it into the fleet of a contemporary airline would be challenging to justify, even if the technical and regulatory concerns could be handled.
- Supersonic flight over land is usually not allowed to minimize the impact on people on the ground. This meant that Concorde could not operate at its maximum Mach 2 speed until it was over an open body of water.
To learn more about Concorde refer to:
brainly.com/question/14354579
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<span>The compound may have properties that are very different from those of the elements it is composed from.</span>
