Answer:
Vestigial Structures
Explanation:
Structures that were needed for an organism's ancestor, but no longer required for survival for the current organism. We needed our wisdom teeth and appendix in order to eat tougher foods, but now we do not need those to survive. But, we still have them.
4.1g
Explanation:
Given parameters:
Mass of carbon dioxide = 15g
Mass of oxygen gas = 11g
Unknown:
Mass of carbon consumed = ?
Solution:
Equation of the reaction:
C + O₂ → CO₂
To solve this problem from the balanced equation, we have to use the amount of product formed and work to Carbon. This is because, we are sure of the amount of carbon dioxide formed but the amount of the given oxygen gas used is not precise.
Number of moles of CO₂ = 
Molar mass of CO₂ = 12 + (16 x2) = 44g/mol
Number of moles of CO₂ =
= 0.34mole
From the equation of the reaction;
1 mole of CO₂ is produced from 1 mole of C
0.34mole of CO₂ will produce 0.34mole of C
Mass of carbon reacting = number of moles x molar mass = 0.34 x 12 = 4.1g
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The branch of chemistry that the chemist might use will be the branch of <em>organic chemistry</em>. This is because gasoline is an organic compound. We can say that a compound is organic if it contains a carbon atom. Gasoline is composed of long chains of alkanes (hydrocarbons with single bonds) ranging from 4 carbon atoms to 12 carbon atoms.
Rust (Fe2O3. 4H2O) is formed when iron interacts slowly with oxygen and water. Mass of Fe in grams is 2.18 x 10⁴ g.
<h3>
What is the explanation?</h3>
There are 2 moles of Fe atoms in 1 mole of Fe2O3-4H2O. The number of moles of Fe atoms in 45.2 kg rust is shown below.
Moles of Fe = 195.01 mol Fe₂O₃.4H₂O (
)
Moles of Fe = 390.02 mol Fe
Multiply the calculated number of moles of iron, Fe, by its molar mass which is 55.85 
Mass of Fe = 390.02 mol Fe (
)
Mass of Fe = 2.18 x 10⁴ g Fe
Avogadro's number (6.022 x 1023) of molecules (or formula units) make up one mole of a substance (ionic compound). The mass of 1 mole of a chemical is indicated by its molar mass. It provides you with the amount of grams per mole of a substance, to put it another way.
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