Question

think like a scientist
read about each scientific investigation. then answer the questions that follow the investigation by selecting the letter next to the best answer.
investigation a
a scientist recently discovered an unknown compound during one of her experiments. to study the unknown compound, she used a technique known as \combustion analysis\ to determine the amount of carbon and hydrogen in the sample. provided below is a diagram showing how a combustion analysis device operates.

1. based on the provided diagram, which of the following substances will initially react with the unknown compound?

a. oxygen gas, o₂
b. sodium hydroxide, naoh
c. magnesium perchlorate, mg(clo₄)₂
d. carbon dioxide gas and water, co₂ and h₂o

Explanation:

Combustion analysis involves burning an unknown compound in oxygen to produce carbon dioxide and water. The diagram shows oxygen gas ($O_2$) is fed into the furnace with the sample, where the initial reaction occurs. The other substances (NaOH, $Mg(ClO_4)_2$, $CO_2/H_2O$) are either products or used to absorb products after the initial reaction.

Answer:

A. oxygen gas, $O_2$