Obi is trying to determine if a powdery, solid substance is an element or a compound. After recording some observations, he strongly heats a sample of the solid over a burner flame. After fifteen minutes, he turns off the flame and allows the sample to cool. He records his final observations in the data table.

A 3-column table with 3 rows. The first column labeled observation has entries appearance, mass (g), chemical reaction with weak acid. The second column labeled original sample has entries white solid, 100.0, bubbles. The third column labeled sample after heating has entries white solid, 56.0, no bubbles.
Which is the best explanation of his results?

A. The heating changed some of the sample to gas, causing the mass to decrease without breaking down the sample. Therefore, the original sample is a compound.

B. The appearance stayed the same, showing that the sample was not broken down by heating. Therefore, the original substance is an element.

C. The mass decreased during heating and some of the impurities escaped. Therefore, the original substance is an element.

D. The chemical reaction with acid changed, showing that the sample was broken down by heating. Therefore, the original substance is a compound.

An element consists of one type of atom and cannot be broken into simpler substances through simple chemical processes

The correct option is option D

D. The chemical reaction with acid changed, showing that the sample was broken down by heating. Therefore, the original substance is a compound

The reason why option D is correct is as follows:

The given table is presented as follows;

[tex]\begin{array}{|l|l|l|}\mathbf{Observation}&\mathbf{Original \ Sample}&\mathbf{Sample \ After \ Heating}\\Appearance&White \ solid&White \ solid\\Mass&100 \, g&56 \, g\\Chemical \ reaction \ with \ acid&Bubbles&No \ bubbles\end{array}\right][/tex]

Given that the changes after heating includes lack of visible reaction with the weak acid, and a significant change in mass, therefore;

The original substance was broken down by heat resulting in a new substance that has different chemical properties. An element cannot be broken down into simpler substances. Therefore, the substance is a compound

The correct option is option D

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3.
Use the equation and the table to answer the question.

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Element Mass of an Atom (amu)
Fe 56
Cl 35
H 1
O 16
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235
92
U +
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0
n →
90
36
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A
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0
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What element is this? Ignore my answer choice.

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4. bundle of energy; zero charge
5. found in nucleus; positive charge
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Words to match to:
alpha
electron
positron
neutrino
proton
beta
gamma
neutron
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