A mixture of 1-heptyne, 2-heptyne, and 3-heptyne was hydrogenated in the presence of a palladium catalyst until hydrogen uptake ceased. How many seven-carbon hydrocarbons were produced

four

Explanation:

Recall that the hydrogenation of 1-heptyne, 2-heptyne, and 3-heptyne  is an addition reaction. The hydrogen is added across the triple bond in the presence of palladium serving as the catalyst.

Note that 1-heptyne and 2-heptyne do not exist as geometric isomers hence they yield one corresponding hydrocarbon each. However, 3-heptyne exhibits geometric isomerism. As a result of this, 3-heptyne yields cis and trans products making a total of four seven-carbon hydrocarbons produced.

The answer to your question is: 54 g

Explanation:

Reaction

                                C  + O₂   ⇒   CO₂

Carbon mass = 18 g

Carbon dioxide mass = 72 g

To solve this question, we must remember the Lavoisier law of conservation of mass, that states that in an isolated of closed system, matter can not be created or destroyed.

This law states that the mass of the reactans must be equal to the mass of the products.

Then

Mass of reactants = 18 + ?

Mass of products = 72

So,

                  18 + x = 72

                  x = 72 - 18

                x = 54 g of oxygen